{"id":7995,"date":"2026-11-06T17:14:27","date_gmt":"2026-11-06T09:14:27","guid":{"rendered":"https:\/\/www.solidess.com\/?p=7995"},"modified":"2026-11-06T17:14:27","modified_gmt":"2026-11-06T09:14:27","slug":"battery-internal-resistance-acir-vs-dcir","status":"publish","type":"post","link":"https:\/\/www.solidess.com\/fr\/battery-internal-resistance-acir-vs-dcir\/","title":{"rendered":"R\u00e9sistance interne d\u2019une batterie : calcul ACIR vs DCIR, essais et guide de coh\u00e9rence des cellules BESS 314 Ah"},"content":{"rendered":"\t\t<div data-elementor-type=\"wp-post\" data-elementor-id=\"7995\" class=\"elementor elementor-7995\" data-elementor-post-type=\"post\">\n\t\t\t\t<div class=\"elementor-element elementor-element-bf4793c e-con-full auto-article-root e-flex e-con e-parent\" data-id=\"bf4793c\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t<div class=\"elementor-element elementor-element-35d78833 auto-p elementor-widget elementor-widget-heading\" data-id=\"35d78833\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">The internal resistance of a battery, expressed in milliohms (m\u03a9), describes the opposition to current flow inside a cell created by its metallic current collectors and tabs, the ionic resistance of the electrolyte and separator, and the electrochemical processes at each electrode interface. AC internal resistance (ACIR) and DC internal resistance (DCIR) are equivalent resistance or impedance results obtained from two different test methods: ACIR from a small 1 kHz alternating signal, and DCIR from the voltage response to a DC current step sampled at a defined time. For example, the SHS180-314Ah <strong><a href=\"https:\/\/www.solidess.com\/bess\/solid-state-battery-technology\/\" style=\"color:#61ce70\">hybrid solid-liquid cell<\/a><\/strong> used across MegSolid's 314Ah storage products, including the <strong><a href=\"https:\/\/www.solidess.com\/megsolid-314ah-hybrid-solid-state-battery\/\" style=\"color:#61ce70\">MegSolid 314Ah Hybrid Solid-State Battery<\/a><\/strong>, lists 0.18 \u00b1 0.03 m\u03a9 AC resistance and 0.4 \u00b1 0.1 m\u03a9 DC resistance on its cell specification sheet, with \u2265 94.5% cell energy efficiency at 0.5P.<\/p>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-9c1685de auto-p elementor-widget elementor-widget-heading\" data-id=\"9c1685de\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">This guide uses 314Ah storage cells, 51.2V packs, and 832V 1P260S strings as reference points instead of small consumer cylindrical cells. It covers the calculation formulas, the electrochemistry behind the ACIR and DCIR gap, practical test methods, how to interpret readings, and the series and parallel consistency issues relevant to our <strong><a href=\"https:\/\/www.solidess.com\/solid-state-energy-storage-systems\/\" style=\"color:#61ce70\">Solid-State Energy Storage Systems<\/a><\/strong>.<\/p>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-5c44d4d2 auto-image elementor-widget elementor-widget-image\" data-id=\"5c44d4d2\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<img fetchpriority=\"high\" decoding=\"async\" width=\"1536\" height=\"864\" src=\"https:\/\/www.solidess.com\/wp-content\/uploads\/2026\/11\/lto-vs-solid-state-lifepo4-key-points-overview-1536x864.webp\" class=\"attachment-1536x1536 size-1536x1536 wp-image-7992\" alt=\"Battery ACIR and DCIR key points infographic comparing 1 kHz AC impedance, DC current step, 314Ah reference cell values and four-wire Kelvin testing\" srcset=\"https:\/\/www.solidess.com\/wp-content\/uploads\/2026\/11\/lto-vs-solid-state-lifepo4-key-points-overview-1536x864.webp 1536w, https:\/\/www.solidess.com\/wp-content\/uploads\/2026\/11\/lto-vs-solid-state-lifepo4-key-points-overview-300x169.webp 300w, https:\/\/www.solidess.com\/wp-content\/uploads\/2026\/11\/lto-vs-solid-state-lifepo4-key-points-overview-1024x576.webp 1024w, https:\/\/www.solidess.com\/wp-content\/uploads\/2026\/11\/lto-vs-solid-state-lifepo4-key-points-overview-768x432.webp 768w, https:\/\/www.solidess.com\/wp-content\/uploads\/2026\/11\/lto-vs-solid-state-lifepo4-key-points-overview-2048x1152.webp 2048w, https:\/\/www.solidess.com\/wp-content\/uploads\/2026\/11\/lto-vs-solid-state-lifepo4-key-points-overview-18x10.webp 18w, https:\/\/www.solidess.com\/wp-content\/uploads\/2026\/11\/lto-vs-solid-state-lifepo4-key-points-overview-600x338.webp 600w\" sizes=\"(max-width: 1536px) 100vw, 1536px\" \/>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-960d5c80 auto-h2 elementor-widget elementor-widget-heading\" data-id=\"960d5c80\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">How to Calculate Internal Resistance of a Battery (Voltage Drop &amp; Two-Step DCIR Formulas)<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-45ed803e auto-p elementor-widget elementor-widget-heading\" data-id=\"45ed803e\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">Engineers searching how to calculate internal resistance of a battery or how to find internal resistance of a battery usually need one of two DC methods: a single load step referenced to resting voltage, or a two-step current method that reduces part of the open-circuit voltage relaxation error.<\/p>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-e1d923db auto-h3 elementor-widget elementor-widget-heading\" data-id=\"e1d923db\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<h3 class=\"elementor-heading-title elementor-size-default\">1. Single-Step Method: Open-Circuit Voltage to Loaded Voltage<\/h3>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-6a92b40f auto-p elementor-widget elementor-widget-heading\" data-id=\"6a92b40f\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">R_internal (\u03a9) = (V_OCV - V_load) \/ (I_load)<\/p>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-7bf80796 elementor-widget-mobile__width-inherit auto-list elementor-icon-list--layout-traditional elementor-list-item-link-full_width elementor-widget elementor-widget-icon-list\" data-id=\"7bf80796\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"icon-list.default\">\n\t\t\t\t\t\t\t<ul class=\"elementor-icon-list-items\">\n\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item\">\n\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-circle\" viewBox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M256 8C119 8 8 119 8 256s111 248 248 248 248-111 248-248S393 8 256 8z\"><\/path><\/svg>\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text\">V_OCV: rested open-circuit voltage before the load is applied (V).<\/span>\n\t\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item\">\n\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-circle\" viewBox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M256 8C119 8 8 119 8 256s111 248 248 248 248-111 248-248S393 8 256 8z\"><\/path><\/svg>\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text\">V_load: terminal voltage at a defined sampling time after applying a constant discharge current, such as 10 s (V).<\/span>\n\t\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item\">\n\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-circle\" viewBox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M256 8C119 8 8 119 8 256s111 248 248 248 248-111 248-248S393 8 256 8z\"><\/path><\/svg>\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text\">I_load: discharge current (A).<\/span>\n\t\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t\t\t<\/ul>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-7eef8c34 auto-p elementor-widget elementor-widget-heading\" data-id=\"7eef8c34\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">Illustrative pack example (hypothetical readings, not a MegSolid test record): a 51.2V pack rests at 52.80V, then sags to 52.10V after 10 s at 100A:<\/p>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-b661dc5a auto-p elementor-widget elementor-widget-heading\" data-id=\"b661dc5a\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">R_10s = (52.80V - 52.10V) \/ (100A) = 0.0070 \u03a9 = 7.0 m\u03a9<\/p>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-fd5b67fc auto-p elementor-widget elementor-widget-heading\" data-id=\"fd5b67fc\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">That pack-level figure includes all 16 cells plus busbars, terminals, the fuse, and the BMS current path. For reference, MegSolid's <strong><a href=\"https:\/\/www.solidess.com\/product\/megsolid-solid-energy-storage-battery\/\" style=\"color:#61ce70\">MEG-Solid-512314FL1<\/a><\/strong> (51.2V \/ 314Ah \/ 16.07 kWh) datasheet lists internal impedance \u2264 15 m\u03a9, and the <strong><a href=\"https:\/\/www.solidess.com\/product\/movable-lithium-battery-pack\/\" style=\"color:#61ce70\">MG 512314<\/a><\/strong> movable unit product page lists \u2264 80 m\u03a9 assemblage impedance. The public pages do not state the measurement method behind either figure, so neither limit should be treated as a DCIR value until the test method is confirmed.<\/p>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-c3640286 auto-h3 elementor-widget elementor-widget-heading\" data-id=\"c3640286\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<h3 class=\"elementor-heading-title elementor-size-default\">2. Two-Step Current Method: Reducing OCV Relaxation Error<\/h3>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-cd958cd5 auto-p elementor-widget elementor-widget-heading\" data-id=\"cd958cd5\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">The single-step method assumes V_OCV is stable, yet a cell that has recently been charged or discharged keeps relaxing for minutes to hours. Two-step methods reduce, but do not fully remove, this error by measuring the voltage at two different currents in quick succession:<\/p>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-60422d64 auto-p elementor-widget elementor-widget-heading\" data-id=\"60422d64\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">DCIR (m\u03a9) = (V_1 - V_2) \/ (I_2 - I_1) \u00d7 1,000<\/p>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-0346413f auto-p elementor-widget elementor-widget-heading\" data-id=\"0346413f\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">Illustrative 314Ah cell example at 50% SoC and 25^\u00b0C (hypothetical readings chosen to sit at the 0.4 m\u03a9 nominal DC value on the SHS180-314Ah sheet):<\/p>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-30bd4fb7 elementor-widget-mobile__width-inherit auto-list elementor-icon-list--layout-traditional elementor-list-item-link-full_width elementor-widget elementor-widget-icon-list\" data-id=\"30bd4fb7\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"icon-list.default\">\n\t\t\t\t\t\t\t<ul class=\"elementor-icon-list-items\">\n\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item\">\n\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-circle\" viewBox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M256 8C119 8 8 119 8 256s111 248 248 248 248-111 248-248S393 8 256 8z\"><\/path><\/svg>\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text\">Step 1: I_1 = 31.4A (0.1C), terminal voltage V_1 = 3.2950V at the end of step 1.<\/span>\n\t\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item\">\n\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-circle\" viewBox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M256 8C119 8 8 119 8 256s111 248 248 248 248-111 248-248S393 8 256 8z\"><\/path><\/svg>\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text\">Step 2: I_2 = 157.0A (0.5C), terminal voltage V_2 = 3.2448V at the defined sampling time in step 2.<\/span>\n\t\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t\t\t<\/ul>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-7d31a487 auto-p elementor-widget elementor-widget-heading\" data-id=\"7d31a487\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">DCIR = (3.2950V - 3.2448V) \/ (157.0A - 31.4A) \u00d7 1,000 = (0.0502V) \/ (125.6A) \u00d7 1,000 = 0.40 m\u03a9<\/p>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-0c62500c auto-image elementor-widget elementor-widget-image\" data-id=\"0c62500c\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<img decoding=\"async\" width=\"1536\" height=\"864\" src=\"https:\/\/www.solidess.com\/wp-content\/uploads\/2026\/11\/cell-benchmark-lto-vs-shs180-314ah-vs-lfp-1536x864.webp\" class=\"attachment-1536x1536 size-1536x1536 wp-image-7993\" alt=\"Two-step DCIR worked example showing 31.4 A at 3.2950 V and 157.0 A at 3.2448 V, yielding 0.40 milliohm DC resistance\" srcset=\"https:\/\/www.solidess.com\/wp-content\/uploads\/2026\/11\/cell-benchmark-lto-vs-shs180-314ah-vs-lfp-1536x864.webp 1536w, https:\/\/www.solidess.com\/wp-content\/uploads\/2026\/11\/cell-benchmark-lto-vs-shs180-314ah-vs-lfp-300x169.webp 300w, https:\/\/www.solidess.com\/wp-content\/uploads\/2026\/11\/cell-benchmark-lto-vs-shs180-314ah-vs-lfp-1024x576.webp 1024w, https:\/\/www.solidess.com\/wp-content\/uploads\/2026\/11\/cell-benchmark-lto-vs-shs180-314ah-vs-lfp-768x432.webp 768w, https:\/\/www.solidess.com\/wp-content\/uploads\/2026\/11\/cell-benchmark-lto-vs-shs180-314ah-vs-lfp-18x10.webp 18w, https:\/\/www.solidess.com\/wp-content\/uploads\/2026\/11\/cell-benchmark-lto-vs-shs180-314ah-vs-lfp-600x338.webp 600w, https:\/\/www.solidess.com\/wp-content\/uploads\/2026\/11\/cell-benchmark-lto-vs-shs180-314ah-vs-lfp.webp 2048w\" sizes=\"(max-width: 1536px) 100vw, 1536px\" \/>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-6f94d9d1 auto-p elementor-widget elementor-widget-heading\" data-id=\"6f94d9d1\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">Engineering boundaries on DCIR calculations:<\/p>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-8356c78f elementor-widget-mobile__width-inherit auto-list elementor-icon-list--layout-traditional elementor-list-item-link-full_width elementor-widget elementor-widget-icon-list\" data-id=\"8356c78f\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"icon-list.default\">\n\t\t\t\t\t\t\t<ul class=\"elementor-icon-list-items\">\n\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item\">\n\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-circle\" viewBox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M256 8C119 8 8 119 8 256s111 248 248 248 248-111 248-248S393 8 256 8z\"><\/path><\/svg>\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text\">Standard reference: IEC 62620 (secondary lithium cells and batteries for industrial applications) is the most relevant performance standard for stationary BESS. It describes an AC method applicable to cells and a DC method applicable to both cells and batteries. IEC 61960-3 contains comparable methods but targets portable applications. IEC 62619 is a safety standard and should not be cited as the resistance test procedure.<\/span>\n\t\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item\">\n\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-circle\" viewBox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M256 8C119 8 8 119 8 256s111 248 248 248 248-111 248-248S393 8 256 8z\"><\/path><\/svg>\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text\">Always state the method and sampling instant: a DCIR value is only meaningful together with its current steps, the time at which each voltage is sampled, SoC, and cell temperature. Writing the sampling time into the label (for example DCIR_1s, DCIR_10s, or DCIR_30s) avoids confusion. As a general trend, a shorter sampling time reflects mostly ohmic and fast interfacial contributions, while longer sampling times include a growing share of diffusion polarization.<\/span>\n\t\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item\">\n\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-circle\" viewBox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M256 8C119 8 8 119 8 256s111 248 248 248 248-111 248-248S393 8 256 8z\"><\/path><\/svg>\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text\">Current limits apply: test currents must stay within the cell or pack datasheet limits. The SHS180-314Ah sheet rates cycle life at 0.5P\/0.5P, so a 1C test step on that cell should only be used if the manufacturer's test procedure permits it.<\/span>\n\t\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t\t\t<\/ul>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-97a9fbb3 auto-h2 elementor-widget elementor-widget-heading\" data-id=\"97a9fbb3\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">ACIR vs. DCIR: Why the Two Battery Internal Resistance Values Differ<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-e6367338 auto-p elementor-widget elementor-widget-heading\" data-id=\"e6367338\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">On the SHS180-314Ah sheet, the nominal DC value (0.4 m\u03a9) is about 2.2 times the nominal AC value (0.18 m\u03a9). A simplified Randles-type equivalent circuit helps explain the gap:<\/p>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-482458b8 auto-p elementor-widget elementor-widget-heading\" data-id=\"482458b8\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">Z = R_\u03a9 + \u2264ft[ (1) \/ (j\u03c9 C_dl) \u2225 \u2264ft( R_ct + Z_W ) ]<\/p>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-0aa90ff5 auto-p elementor-widget elementor-widget-heading\" data-id=\"0aa90ff5\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">In this simplified model, the double-layer capacitance branch (1\/j\u03c9 C_dl) sits in parallel with the series combination of charge-transfer resistance and Warburg diffusion impedance, and the whole interfacial network sits in series with the ohmic resistance. Real cells are often fitted with more elaborate circuits (for example, separate SEI and charge-transfer arcs, or constant-phase elements in place of ideal capacitors); the appropriate model should be selected from Electrochemical Impedance Spectroscopy (EIS) data for the specific cell rather than assumed universally.<\/p>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-2e308cef elementor-widget-mobile__width-inherit auto-list elementor-icon-list--layout-traditional elementor-list-item-link-full_width elementor-widget elementor-widget-icon-list\" data-id=\"2e308cef\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"icon-list.default\">\n\t\t\t\t\t\t\t<ul class=\"elementor-icon-list-items\">\n\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item\">\n\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-circle\" viewBox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M256 8C119 8 8 119 8 256s111 248 248 248 248-111 248-248S393 8 256 8z\"><\/path><\/svg>\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text\">1. Ohmic resistance (R_\u03a9): the near-instantaneous resistance of the current collectors, tabs, welds, separator pores, and bulk electrolyte. A 1 kHz AC milliohm meter reports a value dominated by this high-frequency ohmic response, because the double-layer capacitance offers relatively low impedance at that frequency. The 1 kHz reading is therefore close to, but not strictly equal to, R_\u03a9; inductive effects, contact geometry, and residual interfacial contributions can all influence it.<\/span>\n\t\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item\">\n\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-circle\" viewBox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M256 8C119 8 8 119 8 256s111 248 248 248 248-111 248-248S393 8 256 8z\"><\/path><\/svg>\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text\">2. Charge-transfer and SEI resistance (R_ct): the kinetic barrier for lithium ions to shed their solvation shell, cross the Solid Electrolyte Interphase (SEI), and intercalate into the electrode. A DC step sampled after the interfacial time constant includes a large part of this term.<\/span>\n\t\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item\">\n\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-circle\" viewBox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M256 8C119 8 8 119 8 256s111 248 248 248 248-111 248-248S393 8 256 8z\"><\/path><\/svg>\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text\">3. Diffusion impedance (Z_W, Warburg element): under sustained current, lithium concentration gradients build up inside active material particles and the electrolyte. Longer sampling times capture more of this polarization, which is why DCIR_30s usually reads higher than DCIR_10s on the same cell.<\/span>\n\t\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t\t\t<\/ul>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-1a430e37 auto-h3 elementor-widget elementor-widget-heading\" data-id=\"1a430e37\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<h3 class=\"elementor-heading-title elementor-size-default\">Using DCIR for Simplified Voltage Drop and Loss Estimates<\/h3>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-22e00e87 auto-p elementor-widget elementor-widget-heading\" data-id=\"22e00e87\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">DCIR is useful for first-order estimates of load voltage drop and resistive loss:<\/p>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-ca6a970f auto-p elementor-widget elementor-widget-heading\" data-id=\"ca6a970f\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">\u0394 V \u2248 I \u00b7 DCIR ; P_loss \u2248 I^2 \u00b7 DCIR<\/p>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-dc19e4cc auto-p elementor-widget elementor-widget-heading\" data-id=\"dc19e4cc\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">At 0.5C (157A) on a cell at the 0.4 m\u03a9 nominal DC value, the estimated voltage drop is 157 \u00d7 0.0004 = 0.0628V and the estimated resistive loss is 157^2 \u00d7 0.0004 = 9.86 W per cell.<\/p>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-527e893c auto-p elementor-widget elementor-widget-heading\" data-id=\"527e893c\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">These are simplified equivalent-model estimates, not measured heat generation. Because a measured DCIR value contains polarization contributions that change with sampling time, and because real cell heat also depends on SoC, temperature, dynamic polarization, and reversible entropic heat, I^2 \u00d7 DCIR should not be used as a substitute for a calibrated cell thermal model or calorimetry data. Likewise, a voltage-drop percentage at a single operating point cannot be used to derive the full charge-discharge energy efficiency of a cell; the \u2265 94.5% efficiency on the SHS180-314Ah sheet is a separately tested specification.<\/p>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-98319838 elementor-tablet-align-center elementor-align-center auto-cta elementor-widget elementor-widget-button\" data-id=\"98319838\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"button.default\">\n\t\t\t\t\t\t\t\t\t\t<a class=\"elementor-button elementor-button-link elementor-size-sm\" href=\"#elementor-action%3Aaction%3Dpopup%3Aopen%26settings%3DeyJpZCI6Ijk0OCIsInRvZ2dsZSI6ZmFsc2V9\">\n\t\t\t\t\t\t<span class=\"elementor-button-content-wrapper\">\n\t\t\t\t\t\t\t\t\t<span class=\"elementor-button-text\">Contact Us for an ACIR and DCIR Test Method Review<\/span>\n\t\t\t\t\t<\/span>\n\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-5c4d7851 auto-h2 elementor-widget elementor-widget-heading\" data-id=\"5c4d7851\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Test Internal Resistance of a Battery: What Is a Good Milliohm (m\u03a9) Reading?<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-8ba329f0 auto-p elementor-widget elementor-widget-heading\" data-id=\"8ba329f0\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">For anyone searching test internal resistance battery what is a good reading, the short answer is: a good reading falls inside the manufacturer's datasheet tolerance when measured with the same method, SoC, temperature, and sampling time, and it sits close to the readings of sister cells in the same string. There is no universal \"good\" milliohm value across cell sizes, because resistance scales inversely with capacity and electrode area.<\/p>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-485d08f3 auto-h3 elementor-widget elementor-widget-heading\" data-id=\"485d08f3\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<h3 class=\"elementor-heading-title elementor-size-default\">Table 1: Published Resistance Data &amp; Theoretical Series Examples for 314Ah Storage Products<\/h3>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-33fd3d45 auto-table elementor-widget elementor-widget-text-editor\" data-id=\"33fd3d45\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<div class=\"cea-table-wrap\"><table><thead><tr><th>Unit &amp; Configuration<\/th><th>Published or Calculated Value<\/th><th>Test Method Stated?<\/th><th>Source &amp; Status<\/th><th>Interpretation Note<\/th><\/tr><\/thead><tbody><tr><td>SHS180-314Ah cell (3.2V, 314Ah, 1,005 Wh; used in MegSolid 314Ah products)<\/td><td>AC 0.18 \u00b1 0.03 m\u03a9 (0.15\u20130.21); DC 0.4 \u00b1 0.1 m\u03a9 (0.3\u20130.5)<\/td><td>AC and DC stated; DC pulse details to confirm<\/td><td>Cell specification sheet<\/td><td>Confirm DC current steps, sampling time, and SoC in the original datasheet and batch reports<\/td><\/tr><tr><td>MEG-Solid-512314FL1 pack (51.2V, 314Ah)<\/td><td>Internal impedance \u2264 15 m\u03a9<\/td><td>Not stated (not confirmed as AC or DC)<\/td><td>Official product datasheet<\/td><td>Includes cells, busbars, terminals, and BMS path<\/td><\/tr><tr><td>MG 512314 movable unit (51.2V, 314Ah)<\/td><td>Assemblage impedance \u2264 80 m\u03a9<\/td><td>Not stated (not confirmed as AC or DC)<\/td><td>Official product page<\/td><td>Upper limit for the assembled unit<\/td><\/tr><tr><td>16S cell-only sum (SHS180-314Ah \u00d7 16, as in 51.2V packs)<\/td><td>AC 16 \u00d7 0.18 = 2.88 m\u03a9; DC 16 \u00d7 0.40 = 6.40 m\u03a9<\/td><td>Arithmetic only<\/td><td>Calculated from SHS180-314Ah sheet<\/td><td>Cell contribution only; excludes busbars, fuse, contactors, and BMS shunt<\/td><\/tr><tr><td>260S cell-only sum (SHS180-314Ah \u00d7 260, as in <strong><a href=\"https:\/\/www.solidess.com\/product\/megsolid-solid-liquid-energy-storage\/\" style=\"color:#61ce70\">Energon<\/a><\/strong> 1P260S)<\/td><td>AC 260 \u00d7 0.18 = 46.8 m\u03a9 (39.0\u201354.6); DC 260 \u00d7 0.40 = 104 m\u03a9 (78\u2013130)<\/td><td>Arithmetic only<\/td><td>Calculated from SHS180-314Ah sheet<\/td><td>Cell contribution only; not a published Energon string resistance specification<\/td><\/tr><\/tbody><\/table><\/div>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-a54d3d51 auto-p elementor-widget elementor-widget-heading\" data-id=\"a54d3d51\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">How to read Table 1:<\/p>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-b14e5e03 elementor-widget-mobile__width-inherit auto-list elementor-icon-list--layout-traditional elementor-list-item-link-full_width elementor-widget elementor-widget-icon-list\" data-id=\"b14e5e03\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"icon-list.default\">\n\t\t\t\t\t\t\t<ul class=\"elementor-icon-list-items\">\n\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item\">\n\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-circle\" viewBox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M256 8C119 8 8 119 8 256s111 248 248 248 248-111 248-248S393 8 256 8z\"><\/path><\/svg>\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text\">Cell-only sums are not system values: the 16S and 260S rows add up the SHS180-314Ah cell resistance only, so they are comparable with field readings only when taken under the same method, SoC, temperature, and sampling time. A complete pack or string also includes module busbars, inter-module cables, fuses, contactors, and current shunts, which add further resistance, and cell-to-cell values vary within the datasheet tolerance.<\/span>\n\t\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item\">\n\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-circle\" viewBox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M256 8C119 8 8 119 8 256s111 248 248 248 248-111 248-248S393 8 256 8z\"><\/path><\/svg>\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text\">Trend matters more than a single reading: record a Beginning-of-Life (BOL) baseline at commissioning under a fixed method (same current steps, sampling time, 50% SoC, and stable cell temperature), then track the percentage change over time.<\/span>\n\t\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item\">\n\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-circle\" viewBox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M256 8C119 8 8 119 8 256s111 248 248 248 248-111 248-248S393 8 256 8z\"><\/path><\/svg>\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text\">Empirical inspection approach: some operators use a DCIR rise of roughly 50% above the BOL baseline as a prompt for closer investigation, and a rise approaching 100% as a signal to assess remaining life. This is an empirical screening approach, not a universal industry replacement standard. Alarm and replacement decisions should follow the manufacturer's documentation, warranty terms, and a combined review of capacity (SOH), resistance trend, and cell-to-cell spread.<\/span>\n\t\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item\">\n\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-circle\" viewBox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M256 8C119 8 8 119 8 256s111 248 248 248 248-111 248-248S393 8 256 8z\"><\/path><\/svg>\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text\">Spread inside one string: a single cell reading well above its neighbors, measured under identical conditions, is often a stronger fault indicator than a uniform rise across the whole string.<\/span>\n\t\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t\t\t<\/ul>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-e94b41b1 auto-h3 elementor-widget elementor-widget-heading\" data-id=\"e94b41b1\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<h3 class=\"elementor-heading-title elementor-size-default\">How to Test Internal Resistance Correctly: 4-Wire Kelvin Measurement<\/h3>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-1000244a auto-p elementor-widget elementor-widget-heading\" data-id=\"1000244a\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">Standard 2-wire multimeters cannot resolve a 0.18 m\u03a9 cell, because the voltage drop across the test leads and probe contacts can be many times larger than the value being measured. Reliable testing uses 4-terminal Kelvin sensing:<\/p>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-bd140e8b elementor-widget-mobile__width-inherit auto-list elementor-icon-list--layout-traditional elementor-list-item-link-full_width elementor-widget elementor-widget-icon-list\" data-id=\"bd140e8b\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"icon-list.default\">\n\t\t\t\t\t\t\t<ul class=\"elementor-icon-list-items\">\n\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item\">\n\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-circle\" viewBox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M256 8C119 8 8 119 8 256s111 248 248 248 248-111 248-248S393 8 256 8z\"><\/path><\/svg>\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text\">1. Separate force and sense leads: one pair of leads injects the test current, while a second pair measures voltage at the cell terminal or weld pad. This mainly removes the voltage drop across the test leads and their associated contacts. The position of the sense points still affects the result, because any terminal, weld, or busbar section between the sense points is included in the reading. Keep probe placement identical between tests.<\/span>\n\t\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item\">\n\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-circle\" viewBox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M256 8C119 8 8 119 8 256s111 248 248 248 248-111 248-248S393 8 256 8z\"><\/path><\/svg>\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text\">2. ACIR: use a 1 kHz AC battery milliohm meter with Kelvin probes. Readings are fast and repeatable, which makes ACIR useful for incoming inspection and cell sorting.<\/span>\n\t\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item\">\n\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-circle\" viewBox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M256 8C119 8 8 119 8 256s111 248 248 248 248-111 248-248S393 8 256 8z\"><\/path><\/svg>\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text\">3. DCIR: use a programmable cycler or electronic load with Kelvin voltage sensing, logging voltage at defined sampling times after each current step.<\/span>\n\t\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item\">\n\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-circle\" viewBox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M256 8C119 8 8 119 8 256s111 248 248 248 248-111 248-248S393 8 256 8z\"><\/path><\/svg>\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text\">4. Control the conditions: fix SoC, let the cell rest to thermal equilibrium, and record cell temperature with every reading. Resistance rises noticeably as temperature drops.<\/span>\n\t\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item\">\n\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-circle\" viewBox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M256 8C119 8 8 119 8 256s111 248 248 248 248-111 248-248S393 8 256 8z\"><\/path><\/svg>\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text\">5. Respect voltage ratings: measuring modules or strings at hundreds of volts requires instruments, probes, and personal protective equipment rated for the full DC voltage. Many bench battery testers are limited to a few hundred volts and must not be connected across an 832V string.<\/span>\n\t\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t\t\t<\/ul>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-8e1d9349 auto-h2 elementor-widget elementor-widget-heading\" data-id=\"8e1d9349\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">How Internal Resistance Inconsistency Contributes to the BESS \"Barrel Effect\" &amp; Cluster Circulating Current<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-815d0bba auto-p elementor-widget elementor-widget-heading\" data-id=\"815d0bba\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">In a large stationary battery, the absolute internal resistance of the battery cells matters, but so does how consistent it is from cell to cell and from cluster to cluster.<\/p>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-86a0b8b6 auto-h3 elementor-widget elementor-widget-heading\" data-id=\"86a0b8b6\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<h3 class=\"elementor-heading-title elementor-size-default\">1. Series String Barrel Effect in a 260S Configuration<\/h3>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-ed063030 auto-p elementor-widget elementor-widget-heading\" data-id=\"ed063030\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">In the 1P260S string of the 261.24 kWh Energon cabinet (260 \u00d7 SHS180-314Ah cells, 832V nominal, 676\u2013936V DC), all 260 cells carry the same current. Consider an illustrative 157A (0.5C) current and one aged cell at 0.80 m\u03a9 DCIR beside neighbors at 0.40 m\u03a9 (hypothetical values for illustration only):<\/p>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-5442d539 elementor-widget-mobile__width-inherit auto-list elementor-icon-list--layout-traditional elementor-list-item-link-full_width elementor-widget elementor-widget-icon-list\" data-id=\"5442d539\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"icon-list.default\">\n\t\t\t\t\t\t\t<ul class=\"elementor-icon-list-items\">\n\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item\">\n\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-circle\" viewBox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M256 8C119 8 8 119 8 256s111 248 248 248 248-111 248-248S393 8 256 8z\"><\/path><\/svg>\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text\">1. Possible earlier discharge cutoff: in the simplified model, the aged cell drops an extra 157 \u00d7 (0.80 - 0.40) \u00d7 10^(-3) = 0.0628V under load. Near the steep end of the LFP discharge curve, that extra drop can bring it to its low-voltage limit before its neighbors.<\/span>\n\t\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item\">\n\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-circle\" viewBox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M256 8C119 8 8 119 8 256s111 248 248 248 248-111 248-248S393 8 256 8z\"><\/path><\/svg>\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text\">2. Possible earlier charge cutoff: during charging, the same cell's terminal voltage sits about 0.0628V higher (V_term \u2248 V_OCV + I \u00b7 R), so it can reach the upper limit first.<\/span>\n\t\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item\">\n\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-circle\" viewBox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M256 8C119 8 8 119 8 256s111 248 248 248 248-111 248-248S393 8 256 8z\"><\/path><\/svg>\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text\">3. Higher local loss: in the simplified I^2R estimate, the aged cell's resistive loss is 157^2 \u00d7 0.0008 = 19.7 W versus 9.86 W for its neighbors. Higher local temperature can accelerate SEI growth and further resistance increase.<\/span>\n\t\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t\t\t<\/ul>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-48c413be auto-p elementor-widget elementor-widget-heading\" data-id=\"48c413be\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">Whether a higher-resistance cell actually triggers protection first depends on more than resistance. Each cell's actual capacity, SoC, and OCV position, the BMS balancing capability and strategy, cell temperature, and the operating current all determine which cell reaches a voltage limit first. A lower-capacity cell with normal resistance can limit the string just as much as a high-resistance cell. The usable energy of a series string is governed by the combined spread of capacity, SoC, and resistance, which is why cell grading, balancing, and thermal uniformity all matter.<\/p>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-7197be4e auto-image elementor-widget elementor-widget-image\" data-id=\"7197be4e\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<img decoding=\"async\" width=\"1536\" height=\"864\" src=\"https:\/\/www.solidess.com\/wp-content\/uploads\/2026\/11\/match-cycle-life-to-duty-cycle-lcos-1536x864.webp\" class=\"attachment-1536x1536 size-1536x1536 wp-image-7994\" alt=\"Series battery string barrel effect infographic comparing normal cell DCIR 0.40 milliohm with one aged cell at 0.80 milliohm and increased voltage drop\" srcset=\"https:\/\/www.solidess.com\/wp-content\/uploads\/2026\/11\/match-cycle-life-to-duty-cycle-lcos-1536x864.webp 1536w, https:\/\/www.solidess.com\/wp-content\/uploads\/2026\/11\/match-cycle-life-to-duty-cycle-lcos-300x169.webp 300w, https:\/\/www.solidess.com\/wp-content\/uploads\/2026\/11\/match-cycle-life-to-duty-cycle-lcos-1024x576.webp 1024w, https:\/\/www.solidess.com\/wp-content\/uploads\/2026\/11\/match-cycle-life-to-duty-cycle-lcos-768x432.webp 768w, https:\/\/www.solidess.com\/wp-content\/uploads\/2026\/11\/match-cycle-life-to-duty-cycle-lcos-18x10.webp 18w, https:\/\/www.solidess.com\/wp-content\/uploads\/2026\/11\/match-cycle-life-to-duty-cycle-lcos-600x338.webp 600w, https:\/\/www.solidess.com\/wp-content\/uploads\/2026\/11\/match-cycle-life-to-duty-cycle-lcos.webp 2048w\" sizes=\"(max-width: 1536px) 100vw, 1536px\" \/>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-e41e5d94 auto-h3 elementor-widget elementor-widget-heading\" data-id=\"e41e5d94\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<h3 class=\"elementor-heading-title elementor-size-default\">2. Parallel Cluster Current Sharing and Circulating Current<\/h3>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-bf1e3ba3 auto-p elementor-widget elementor-widget-heading\" data-id=\"bf1e3ba3\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">When battery clusters are paralleled directly on a common DC bus, a simple resistive model illustrates two effects:<\/p>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-f0f60a35 elementor-widget-mobile__width-inherit auto-list elementor-icon-list--layout-traditional elementor-list-item-link-full_width elementor-widget elementor-widget-icon-list\" data-id=\"f0f60a35\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"icon-list.default\">\n\t\t\t\t\t\t\t<ul class=\"elementor-icon-list-items\">\n\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item\">\n\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-circle\" viewBox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M256 8C119 8 8 119 8 256s111 248 248 248 248-111 248-248S393 8 256 8z\"><\/path><\/svg>\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text\">Unequal current sharing: with equal open-circuit voltages and purely resistive behavior, current divides in inverse proportion to resistance (I_A \/ I_B = R_B \/ R_A). If Cluster A measures 104 m\u03a9 and Cluster B measures 130 m\u03a9 (illustrative values), Cluster A carries 130 \/ 104 = 1.25 times the current of Cluster B.<\/span>\n\t\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item\">\n\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-circle\" viewBox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M256 8C119 8 8 119 8 256s111 248 248 248 248-111 248-248S393 8 256 8z\"><\/path><\/svg>\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text\">Circulating current: if cluster voltages differ when contactors close, current flows from the higher cluster into the lower one, approximately I_circ = \u0394 V \/ (R_A + R_B). An illustrative 5V difference across 104 + 130 = 234 m\u03a9 gives about 21A between clusters, even with zero load.<\/span>\n\t\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t\t\t<\/ul>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-b6b15f2e auto-p elementor-widget elementor-widget-heading\" data-id=\"b6b15f2e\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">In practice, current distribution also depends on each cluster's OCV and SoC, dynamic polarization during load changes, cable and protection-device resistance, and the control architecture (for example, whether each cluster has its own DC\/DC stage or PCS, and how pre-charge and contactor sequencing are managed). The resistive model above is a starting point for analysis, not a full system simulation.<\/p>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-0c82a4c4 auto-p elementor-widget elementor-widget-heading\" data-id=\"0c82a4c4\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">For MegSolid systems, the Energon cabinet is specified with a 125 kVA AC rating and supports parallel operation of up to 10 units. These published figures do not by themselves define the final multi-cabinet connection topology, so cluster coupling and current-sharing design must be confirmed from the project single-line diagram and system documentation.<\/p>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-579c56c1 auto-h2 elementor-widget elementor-widget-heading\" data-id=\"579c56c1\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">How MegSolid Addresses Internal Resistance at Cell, Pack &amp; System Level<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-4cafe032 auto-p elementor-widget elementor-widget-heading\" data-id=\"4cafe032\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">Table 2 separates what MegSolid publishes from what buyers should request in project documentation.<\/p>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-77a6715d auto-h3 elementor-widget elementor-widget-heading\" data-id=\"77a6715d\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<h3 class=\"elementor-heading-title elementor-size-default\">Table 2: Published MegSolid Data vs. Items to Verify in Procurement<\/h3>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-425d3e8d auto-table elementor-widget elementor-widget-text-editor\" data-id=\"425d3e8d\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<div class=\"cea-table-wrap\"><table><thead><tr><th>Engineering Layer<\/th><th>Published MegSolid Data<\/th><th>What to Request or Verify<\/th><th>Why It Matters for Internal Resistance<\/th><\/tr><\/thead><tbody><tr><td>Cell<\/td><td>SHS180-314Ah (used in MegSolid 314Ah packs, Energon, and <strong><a href=\"https:\/\/www.solidess.com\/product\/megsolid-containerized-energy-storage-system-5000intl\/\" style=\"color:#61ce70\">5000INTL<\/a><\/strong>): 0.18 \u00b1 0.03 m\u03a9 AC, 0.4 \u00b1 0.1 m\u03a9 DC, \u2265 94.5% energy efficiency @ 0.5P<\/td><td>Original cell datasheet, DC test method and sampling time, and batch test reports<\/td><td>Low baseline resistance reduces voltage sag and resistive loss<\/td><\/tr><tr><td>Cell grading<\/td><td>Grading criteria not published<\/td><td>Sorting parameters (capacity, OCV, ACIR, self-discharge K-value, DCIR) and allowed spread per string<\/td><td>Tight matching reduces the series barrel effect<\/td><\/tr><tr><td>Pack<\/td><td>MEG-Solid-512314FL1 internal impedance \u2264 15 m\u03a9; MG 512314 \u2264 80 m\u03a9 assemblage impedance (methods not stated)<\/td><td>Pack resistance test method (AC or DC), sense-point locations, and delivery acceptance limit<\/td><td>Captures busbar, weld, and terminal quality<\/td><\/tr><tr><td>Thermal<\/td><td>Energon liquid cooling, -20^\u00b0C to +55^\u00b0C (derated above 45^\u00b0C); cell temperature difference target of 1^\u00b0C to 3^\u00b0C to be confirmed<\/td><td>Controlled specification and test conditions for the temperature-difference figure<\/td><td>Even temperature helps keep resistance aging uniform across cells<\/td><\/tr><tr><td>System<\/td><td>Energon 261.24 kWh \/ 125 kVA, 1P260S, parallel up to 10 units; 5000INTL 5,015.9 kWh \/ 2,700 kW, smart liquid cooling<\/td><td>Cluster topology, single-line diagram, DC bus arrangement, and BMS resistance-trend monitoring<\/td><td>Determines exposure to cluster current imbalance<\/td><\/tr><\/tbody><\/table><\/div>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-b34d089d auto-p elementor-widget elementor-widget-heading\" data-id=\"b34d089d\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">Practical takeaways for EPC and O&amp;M teams:<\/p>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-9a76ce27 elementor-widget-mobile__width-inherit auto-list elementor-icon-list--layout-traditional elementor-list-item-link-full_width elementor-widget elementor-widget-icon-list\" data-id=\"9a76ce27\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"icon-list.default\">\n\t\t\t\t\t\t\t<ul class=\"elementor-icon-list-items\">\n\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item\">\n\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-circle\" viewBox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M256 8C119 8 8 119 8 256s111 248 248 248 248-111 248-248S393 8 256 8z\"><\/path><\/svg>\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text\">1. Ask for cell-level resistance data together with the test method and sampling time, not a single headline number.<\/span>\n\t\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item\">\n\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-circle\" viewBox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M256 8C119 8 8 119 8 256s111 248 248 248 248-111 248-248S393 8 256 8z\"><\/path><\/svg>\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text\">2. Record ACIR and DCIR baselines at commissioning, then trend them under identical conditions.<\/span>\n\t\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item\">\n\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-circle\" viewBox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M256 8C119 8 8 119 8 256s111 248 248 248 248-111 248-248S393 8 256 8z\"><\/path><\/svg>\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text\">3. Review outlier cells together with capacity, SoC, and balancing data rather than relying on average string resistance alone.<\/span>\n\t\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t\t\t<\/ul>\n\t\t\t\t\t\t<\/div>\n\t\t<div class=\"elementor-element elementor-element-480cd0a5 auto-faq e-flex e-con-boxed e-con e-child\" data-id=\"480cd0a5\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t\t\t<div class=\"elementor-element elementor-element-20697a43 elementor-widget elementor-widget-heading\" data-id=\"20697a43\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">FAQ<\/h2>\t\t\t\t<\/div>\n\t\t<div class=\"elementor-element elementor-element-20c946e8 e-con-full e-flex e-con e-child\" data-id=\"20c946e8\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t<div class=\"elementor-element elementor-element-337737eb elementor-widget elementor-widget-n-accordion\" data-id=\"337737eb\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;default_state&quot;:&quot;all_collapsed&quot;,&quot;max_items_expended&quot;:&quot;one&quot;,&quot;n_accordion_animation_duration&quot;:{&quot;unit&quot;:&quot;ms&quot;,&quot;size&quot;:400,&quot;sizes&quot;:[]}}\" data-widget_type=\"nested-accordion.default\">\n\t\t\t\t\t\t\t<div class=\"e-n-accordion\" aria-label=\"Accordion. Open links with Enter or Space, close with Escape, and navigate with Arrow Keys\">\n\t\t\t\t\t\t<details id=\"e-n-accordion-item-8630\" class=\"e-n-accordion-item\" >\n\t\t\t\t<summary class=\"e-n-accordion-item-title\" data-accordion-index=\"1\" tabindex=\"0\" aria-expanded=\"false\" aria-controls=\"e-n-accordion-item-8630\" >\n\t\t\t\t\t<span class='e-n-accordion-item-title-header'><div class=\"e-n-accordion-item-title-text\"> Does the internal resistance of a battery change with temperature? <\/div><\/span>\n\t\t\t\t\t\t\t<span class='e-n-accordion-item-title-icon'>\n\t\t\t<span class='e-opened' ><svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-chevron-up\" viewBox=\"0 0 448 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M240.971 130.524l194.343 194.343c9.373 9.373 9.373 24.569 0 33.941l-22.667 22.667c-9.357 9.357-24.522 9.375-33.901.04L224 227.495 69.255 381.516c-9.379 9.335-24.544 9.317-33.901-.04l-22.667-22.667c-9.373-9.373-9.373-24.569 0-33.941L207.03 130.525c9.372-9.373 24.568-9.373 33.941-.001z\"><\/path><\/svg><\/span>\n\t\t\t<span class='e-closed'><svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-chevron-down\" viewBox=\"0 0 448 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M207.029 381.476L12.686 187.132c-9.373-9.373-9.373-24.569 0-33.941l22.667-22.667c9.357-9.357 24.522-9.375 33.901-.04L224 284.505l154.745-154.021c9.379-9.335 24.544-9.317 33.901.04l22.667 22.667c9.373 9.373 9.373 24.569 0 33.941L240.971 381.476c-9.373 9.372-24.569 9.372-33.942 0z\"><\/path><\/svg><\/span>\n\t\t<\/span>\n\n\t\t\t\t\t\t<\/summary>\n\t\t\t\t<div role=\"region\" aria-labelledby=\"e-n-accordion-item-8630\" class=\"elementor-element elementor-element-37b716ab e-con-full e-flex e-con e-child\" data-id=\"37b716ab\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t<div role=\"region\" aria-labelledby=\"e-n-accordion-item-8630\" class=\"elementor-element elementor-element-2cbb525f e-con-full e-flex e-con e-child\" data-id=\"2cbb525f\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t<div class=\"elementor-element elementor-element-69e679b1 elementor-widget elementor-widget-heading\" data-id=\"69e679b1\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">Yes. In the short term, lithium cell resistance rises as temperature falls, because electrolyte viscosity increases and charge-transfer kinetics slow down. Below 0^\u00b0C, DCIR can reach several times its 25^\u00b0C value, depending on chemistry, SoC, and test method. Warming a cell lowers its resistance temporarily, but prolonged operation at high temperature accelerates SEI growth and can permanently raise the baseline. Always compare readings at a stated temperature.<\/p>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/details>\n\t\t\t\t\t\t<details id=\"e-n-accordion-item-8631\" class=\"e-n-accordion-item\" >\n\t\t\t\t<summary class=\"e-n-accordion-item-title\" data-accordion-index=\"2\" tabindex=\"-1\" aria-expanded=\"false\" aria-controls=\"e-n-accordion-item-8631\" >\n\t\t\t\t\t<span class='e-n-accordion-item-title-header'><div class=\"e-n-accordion-item-title-text\"> Why is ACIR lower than DCIR in a lithium battery? <\/div><\/span>\n\t\t\t\t\t\t\t<span class='e-n-accordion-item-title-icon'>\n\t\t\t<span class='e-opened' ><svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-chevron-up\" viewBox=\"0 0 448 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M240.971 130.524l194.343 194.343c9.373 9.373 9.373 24.569 0 33.941l-22.667 22.667c-9.357 9.357-24.522 9.375-33.901.04L224 227.495 69.255 381.516c-9.379 9.335-24.544 9.317-33.901-.04l-22.667-22.667c-9.373-9.373-9.373-24.569 0-33.941L207.03 130.525c9.372-9.373 24.568-9.373 33.941-.001z\"><\/path><\/svg><\/span>\n\t\t\t<span class='e-closed'><svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-chevron-down\" viewBox=\"0 0 448 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M207.029 381.476L12.686 187.132c-9.373-9.373-9.373-24.569 0-33.941l22.667-22.667c9.357-9.357 24.522-9.375 33.901-.04L224 284.505l154.745-154.021c9.379-9.335 24.544-9.317 33.901.04l22.667 22.667c9.373 9.373 9.373 24.569 0 33.941L240.971 381.476c-9.373 9.372-24.569 9.372-33.942 0z\"><\/path><\/svg><\/span>\n\t\t<\/span>\n\n\t\t\t\t\t\t<\/summary>\n\t\t\t\t<div role=\"region\" aria-labelledby=\"e-n-accordion-item-8631\" class=\"elementor-element elementor-element-9dcc10f1 e-con-full e-flex e-con e-child\" data-id=\"9dcc10f1\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t<div role=\"region\" aria-labelledby=\"e-n-accordion-item-8631\" class=\"elementor-element elementor-element-09fa118a e-con-full e-flex e-con e-child\" data-id=\"09fa118a\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t<div class=\"elementor-element elementor-element-470716cf elementor-widget elementor-widget-heading\" data-id=\"470716cf\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">ACIR uses a 1 kHz signal, and the result is dominated by the high-frequency ohmic response because slower interfacial and diffusion processes contribute little at that frequency. DCIR applies a sustained current step and samples the voltage after a defined time, so it adds charge-transfer, SEI, and diffusion polarization. On the SHS180-314Ah cell sheet, the nominal DC value (0.4 m\u03a9) is about 2.2 times the nominal AC value (0.18 m\u03a9).<\/p>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/details>\n\t\t\t\t\t\t<details id=\"e-n-accordion-item-8632\" class=\"e-n-accordion-item\" >\n\t\t\t\t<summary class=\"e-n-accordion-item-title\" data-accordion-index=\"3\" tabindex=\"-1\" aria-expanded=\"false\" aria-controls=\"e-n-accordion-item-8632\" >\n\t\t\t\t\t<span class='e-n-accordion-item-title-header'><div class=\"e-n-accordion-item-title-text\"> Can I measure battery internal resistance with a multimeter? <\/div><\/span>\n\t\t\t\t\t\t\t<span class='e-n-accordion-item-title-icon'>\n\t\t\t<span class='e-opened' ><svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-chevron-up\" viewBox=\"0 0 448 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M240.971 130.524l194.343 194.343c9.373 9.373 9.373 24.569 0 33.941l-22.667 22.667c-9.357 9.357-24.522 9.375-33.901.04L224 227.495 69.255 381.516c-9.379 9.335-24.544 9.317-33.901-.04l-22.667-22.667c-9.373-9.373-9.373-24.569 0-33.941L207.03 130.525c9.372-9.373 24.568-9.373 33.941-.001z\"><\/path><\/svg><\/span>\n\t\t\t<span class='e-closed'><svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-chevron-down\" viewBox=\"0 0 448 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M207.029 381.476L12.686 187.132c-9.373-9.373-9.373-24.569 0-33.941l22.667-22.667c9.357-9.357 24.522-9.375 33.901-.04L224 284.505l154.745-154.021c9.379-9.335 24.544-9.317 33.901.04l22.667 22.667c9.373 9.373 9.373 24.569 0 33.941L240.971 381.476c-9.373 9.372-24.569 9.372-33.942 0z\"><\/path><\/svg><\/span>\n\t\t<\/span>\n\n\t\t\t\t\t\t<\/summary>\n\t\t\t\t<div role=\"region\" aria-labelledby=\"e-n-accordion-item-8632\" class=\"elementor-element elementor-element-59d17349 e-con-full e-flex e-con e-child\" data-id=\"59d17349\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t<div role=\"region\" aria-labelledby=\"e-n-accordion-item-8632\" class=\"elementor-element elementor-element-22a521b2 e-con-full e-flex e-con e-child\" data-id=\"22a521b2\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t<div class=\"elementor-element elementor-element-95d849ac elementor-widget elementor-widget-heading\" data-id=\"95d849ac\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">Not for large-format storage cells. A 314Ah cell's resistance is a fraction of a milliohm, far below the lead and contact voltage drop of a 2-wire meter. Use a 4-wire Kelvin AC milliohm meter for ACIR, or a cycler or electronic load with Kelvin sensing for DCIR, and keep sense-point placement consistent.<\/p>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/details>\n\t\t\t\t\t\t<details id=\"e-n-accordion-item-8633\" class=\"e-n-accordion-item\" >\n\t\t\t\t<summary class=\"e-n-accordion-item-title\" data-accordion-index=\"4\" tabindex=\"-1\" aria-expanded=\"false\" aria-controls=\"e-n-accordion-item-8633\" >\n\t\t\t\t\t<span class='e-n-accordion-item-title-header'><div class=\"e-n-accordion-item-title-text\"> At what internal resistance should a BESS cell or module be replaced? <\/div><\/span>\n\t\t\t\t\t\t\t<span class='e-n-accordion-item-title-icon'>\n\t\t\t<span class='e-opened' ><svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-chevron-up\" viewBox=\"0 0 448 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M240.971 130.524l194.343 194.343c9.373 9.373 9.373 24.569 0 33.941l-22.667 22.667c-9.357 9.357-24.522 9.375-33.901.04L224 227.495 69.255 381.516c-9.379 9.335-24.544 9.317-33.901-.04l-22.667-22.667c-9.373-9.373-9.373-24.569 0-33.941L207.03 130.525c9.372-9.373 24.568-9.373 33.941-.001z\"><\/path><\/svg><\/span>\n\t\t\t<span class='e-closed'><svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-chevron-down\" viewBox=\"0 0 448 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M207.029 381.476L12.686 187.132c-9.373-9.373-9.373-24.569 0-33.941l22.667-22.667c9.357-9.357 24.522-9.375 33.901-.04L224 284.505l154.745-154.021c9.379-9.335 24.544-9.317 33.901.04l22.667 22.667c9.373 9.373 9.373 24.569 0 33.941L240.971 381.476c-9.373 9.372-24.569 9.372-33.942 0z\"><\/path><\/svg><\/span>\n\t\t<\/span>\n\n\t\t\t\t\t\t<\/summary>\n\t\t\t\t<div role=\"region\" aria-labelledby=\"e-n-accordion-item-8633\" class=\"elementor-element elementor-element-f774711b e-con-full e-flex e-con e-child\" data-id=\"f774711b\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t<div role=\"region\" aria-labelledby=\"e-n-accordion-item-8633\" class=\"elementor-element elementor-element-393b44a4 e-con-full e-flex e-con e-child\" data-id=\"393b44a4\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t<div class=\"elementor-element elementor-element-73639b88 elementor-widget elementor-widget-heading\" data-id=\"73639b88\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">There is no universal resistance threshold for replacement. Some operators use a DCIR rise of around 50% over the commissioning baseline as a trigger for closer inspection and a rise approaching 100% as a prompt to assess remaining life, but this is an empirical screening approach rather than an industry-wide standard. Replacement decisions should combine resistance trend, capacity fade (SOH), cell-to-cell spread, and the manufacturer's warranty criteria.<\/p>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/details>\n\t\t\t\t\t\t<details id=\"e-n-accordion-item-8634\" class=\"e-n-accordion-item\" >\n\t\t\t\t<summary class=\"e-n-accordion-item-title\" data-accordion-index=\"5\" tabindex=\"-1\" aria-expanded=\"false\" aria-controls=\"e-n-accordion-item-8634\" >\n\t\t\t\t\t<span class='e-n-accordion-item-title-header'><div class=\"e-n-accordion-item-title-text\"> How do you calculate DC internal resistance using one load step? <\/div><\/span>\n\t\t\t\t\t\t\t<span class='e-n-accordion-item-title-icon'>\n\t\t\t<span class='e-opened' ><svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-chevron-up\" viewBox=\"0 0 448 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M240.971 130.524l194.343 194.343c9.373 9.373 9.373 24.569 0 33.941l-22.667 22.667c-9.357 9.357-24.522 9.375-33.901.04L224 227.495 69.255 381.516c-9.379 9.335-24.544 9.317-33.901-.04l-22.667-22.667c-9.373-9.373-9.373-24.569 0-33.941L207.03 130.525c9.372-9.373 24.568-9.373 33.941-.001z\"><\/path><\/svg><\/span>\n\t\t\t<span class='e-closed'><svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-chevron-down\" viewBox=\"0 0 448 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M207.029 381.476L12.686 187.132c-9.373-9.373-9.373-24.569 0-33.941l22.667-22.667c9.357-9.357 24.522-9.375 33.901-.04L224 284.505l154.745-154.021c9.379-9.335 24.544-9.317 33.901.04l22.667 22.667c9.373 9.373 9.373 24.569 0 33.941L240.971 381.476c-9.373 9.372-24.569 9.372-33.942 0z\"><\/path><\/svg><\/span>\n\t\t<\/span>\n\n\t\t\t\t\t\t<\/summary>\n\t\t\t\t<div role=\"region\" aria-labelledby=\"e-n-accordion-item-8634\" class=\"elementor-element elementor-element-2f17142e e-con-full e-flex e-con e-child\" data-id=\"2f17142e\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t<div role=\"region\" aria-labelledby=\"e-n-accordion-item-8634\" class=\"elementor-element elementor-element-823ec8f7 e-con-full e-flex e-con e-child\" data-id=\"823ec8f7\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t<div class=\"elementor-element elementor-element-a14b1433 elementor-widget elementor-widget-heading\" data-id=\"a14b1433\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">Measure rested open-circuit voltage, apply a permitted constant discharge current, then record loaded terminal voltage at a defined sampling time. Calculate R = (V_OCV \u2212 V_load) \/ I_load. In the article\u2019s illustrative 51.2V pack example, (52.80 \u2212 52.10)V \u00f7 100A = 0.007\u03a9, or 7.0m\u03a9 at 10 seconds.<\/p>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/details>\n\t\t\t\t\t\t<details id=\"e-n-accordion-item-8635\" class=\"e-n-accordion-item\" >\n\t\t\t\t<summary class=\"e-n-accordion-item-title\" data-accordion-index=\"6\" tabindex=\"-1\" aria-expanded=\"false\" aria-controls=\"e-n-accordion-item-8635\" >\n\t\t\t\t\t<span class='e-n-accordion-item-title-header'><div class=\"e-n-accordion-item-title-text\"> How do you calculate DCIR with two current steps on a 314Ah cell? <\/div><\/span>\n\t\t\t\t\t\t\t<span class='e-n-accordion-item-title-icon'>\n\t\t\t<span class='e-opened' ><svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-chevron-up\" viewBox=\"0 0 448 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M240.971 130.524l194.343 194.343c9.373 9.373 9.373 24.569 0 33.941l-22.667 22.667c-9.357 9.357-24.522 9.375-33.901.04L224 227.495 69.255 381.516c-9.379 9.335-24.544 9.317-33.901-.04l-22.667-22.667c-9.373-9.373-9.373-24.569 0-33.941L207.03 130.525c9.372-9.373 24.568-9.373 33.941-.001z\"><\/path><\/svg><\/span>\n\t\t\t<span class='e-closed'><svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-chevron-down\" viewBox=\"0 0 448 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M207.029 381.476L12.686 187.132c-9.373-9.373-9.373-24.569 0-33.941l22.667-22.667c9.357-9.357 24.522-9.375 33.901-.04L224 284.505l154.745-154.021c9.379-9.335 24.544-9.317 33.901.04l22.667 22.667c9.373 9.373 9.373 24.569 0 33.941L240.971 381.476c-9.373 9.372-24.569 9.372-33.942 0z\"><\/path><\/svg><\/span>\n\t\t<\/span>\n\n\t\t\t\t\t\t<\/summary>\n\t\t\t\t<div role=\"region\" aria-labelledby=\"e-n-accordion-item-8635\" class=\"elementor-element elementor-element-890e1a4d e-con-full e-flex e-con e-child\" data-id=\"890e1a4d\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t<div role=\"region\" aria-labelledby=\"e-n-accordion-item-8635\" class=\"elementor-element elementor-element-04ebd696 e-con-full e-flex e-con e-child\" data-id=\"04ebd696\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t<div class=\"elementor-element elementor-element-0a08b0ba elementor-widget elementor-widget-heading\" data-id=\"0a08b0ba\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">Take two voltage readings at defined currents and matched sampling conditions, then use DCIR (m\u03a9) = (V1 \u2212 V2) \/ (I2 \u2212 I1) \u00d7 1,000. The article\u2019s hypothetical example uses 3.2950V at 31.4A and 3.2448V at 157.0A, yielding 0.40m\u03a9. This is an illustration, not a factory test record.<\/p>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/details>\n\t\t\t\t\t\t<details id=\"e-n-accordion-item-8636\" class=\"e-n-accordion-item\" >\n\t\t\t\t<summary class=\"e-n-accordion-item-title\" data-accordion-index=\"7\" tabindex=\"-1\" aria-expanded=\"false\" aria-controls=\"e-n-accordion-item-8636\" >\n\t\t\t\t\t<span class='e-n-accordion-item-title-header'><div class=\"e-n-accordion-item-title-text\"> What is a good ACIR or DCIR reading for a 314Ah battery cell? <\/div><\/span>\n\t\t\t\t\t\t\t<span class='e-n-accordion-item-title-icon'>\n\t\t\t<span class='e-opened' ><svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-chevron-up\" viewBox=\"0 0 448 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M240.971 130.524l194.343 194.343c9.373 9.373 9.373 24.569 0 33.941l-22.667 22.667c-9.357 9.357-24.522 9.375-33.901.04L224 227.495 69.255 381.516c-9.379 9.335-24.544 9.317-33.901-.04l-22.667-22.667c-9.373-9.373-9.373-24.569 0-33.941L207.03 130.525c9.372-9.373 24.568-9.373 33.941-.001z\"><\/path><\/svg><\/span>\n\t\t\t<span class='e-closed'><svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-chevron-down\" viewBox=\"0 0 448 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M207.029 381.476L12.686 187.132c-9.373-9.373-9.373-24.569 0-33.941l22.667-22.667c9.357-9.357 24.522-9.375 33.901-.04L224 284.505l154.745-154.021c9.379-9.335 24.544-9.317 33.901.04l22.667 22.667c9.373 9.373 9.373 24.569 0 33.941L240.971 381.476c-9.373 9.372-24.569 9.372-33.942 0z\"><\/path><\/svg><\/span>\n\t\t<\/span>\n\n\t\t\t\t\t\t<\/summary>\n\t\t\t\t<div role=\"region\" aria-labelledby=\"e-n-accordion-item-8636\" class=\"elementor-element elementor-element-cbb0326b e-con-full e-flex e-con e-child\" data-id=\"cbb0326b\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t<div role=\"region\" aria-labelledby=\"e-n-accordion-item-8636\" class=\"elementor-element elementor-element-cac0cc7f e-con-full e-flex e-con e-child\" data-id=\"cac0cc7f\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t<div class=\"elementor-element elementor-element-88f25d5c elementor-widget elementor-widget-heading\" data-id=\"88f25d5c\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">A good reading matches the exact cell datasheet tolerance at a comparable SoC, temperature and test method. MegSolid\u2019s SHS180-314Ah cell sheet lists AC resistance of 0.18 \u00b1 0.03m\u03a9 and DC resistance of 0.4 \u00b1 0.1m\u03a9. These values must not be applied as universal thresholds to other cells or complete battery packs.<\/p>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/details>\n\t\t\t\t\t\t<details id=\"e-n-accordion-item-8637\" class=\"e-n-accordion-item\" >\n\t\t\t\t<summary class=\"e-n-accordion-item-title\" data-accordion-index=\"8\" tabindex=\"-1\" aria-expanded=\"false\" aria-controls=\"e-n-accordion-item-8637\" >\n\t\t\t\t\t<span class='e-n-accordion-item-title-header'><div class=\"e-n-accordion-item-title-text\"> Why should ACIR and DCIR be measured at a fixed SoC and temperature? <\/div><\/span>\n\t\t\t\t\t\t\t<span class='e-n-accordion-item-title-icon'>\n\t\t\t<span class='e-opened' ><svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-chevron-up\" viewBox=\"0 0 448 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M240.971 130.524l194.343 194.343c9.373 9.373 9.373 24.569 0 33.941l-22.667 22.667c-9.357 9.357-24.522 9.375-33.901.04L224 227.495 69.255 381.516c-9.379 9.335-24.544 9.317-33.901-.04l-22.667-22.667c-9.373-9.373-9.373-24.569 0-33.941L207.03 130.525c9.372-9.373 24.568-9.373 33.941-.001z\"><\/path><\/svg><\/span>\n\t\t\t<span class='e-closed'><svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-chevron-down\" viewBox=\"0 0 448 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M207.029 381.476L12.686 187.132c-9.373-9.373-9.373-24.569 0-33.941l22.667-22.667c9.357-9.357 24.522-9.375 33.901-.04L224 284.505l154.745-154.021c9.379-9.335 24.544-9.317 33.901.04l22.667 22.667c9.373 9.373 9.373 24.569 0 33.941L240.971 381.476c-9.373 9.372-24.569 9.372-33.942 0z\"><\/path><\/svg><\/span>\n\t\t<\/span>\n\n\t\t\t\t\t\t<\/summary>\n\t\t\t\t<div role=\"region\" aria-labelledby=\"e-n-accordion-item-8637\" class=\"elementor-element elementor-element-84d2d070 e-con-full e-flex e-con e-child\" data-id=\"84d2d070\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t<div role=\"region\" aria-labelledby=\"e-n-accordion-item-8637\" class=\"elementor-element elementor-element-3fe60030 e-con-full e-flex e-con e-child\" data-id=\"3fe60030\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t<div class=\"elementor-element elementor-element-7be1998f elementor-widget elementor-widget-heading\" data-id=\"7be1998f\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">Internal resistance changes with temperature, SoC and the time after a current change. Comparing a cold cell at low SoC with a warm, rested commissioning reading can create a false aging signal. Keep current steps, sampling time, Kelvin probe position, cell temperature and SoC consistent when trending battery health.<\/p>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/details>\n\t\t\t\t\t\t<details id=\"e-n-accordion-item-8638\" class=\"e-n-accordion-item\" >\n\t\t\t\t<summary class=\"e-n-accordion-item-title\" data-accordion-index=\"9\" tabindex=\"-1\" aria-expanded=\"false\" aria-controls=\"e-n-accordion-item-8638\" >\n\t\t\t\t\t<span class='e-n-accordion-item-title-header'><div class=\"e-n-accordion-item-title-text\"> Can you multiply cell ACIR or DCIR by 260 to obtain Energon cabinet resistance? <\/div><\/span>\n\t\t\t\t\t\t\t<span class='e-n-accordion-item-title-icon'>\n\t\t\t<span class='e-opened' ><svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-chevron-up\" viewBox=\"0 0 448 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M240.971 130.524l194.343 194.343c9.373 9.373 9.373 24.569 0 33.941l-22.667 22.667c-9.357 9.357-24.522 9.375-33.901.04L224 227.495 69.255 381.516c-9.379 9.335-24.544 9.317-33.901-.04l-22.667-22.667c-9.373-9.373-9.373-24.569 0-33.941L207.03 130.525c9.372-9.373 24.568-9.373 33.941-.001z\"><\/path><\/svg><\/span>\n\t\t\t<span class='e-closed'><svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-chevron-down\" viewBox=\"0 0 448 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M207.029 381.476L12.686 187.132c-9.373-9.373-9.373-24.569 0-33.941l22.667-22.667c9.357-9.357 24.522-9.375 33.901-.04L224 284.505l154.745-154.021c9.379-9.335 24.544-9.317 33.901.04l22.667 22.667c9.373 9.373 9.373 24.569 0 33.941L240.971 381.476c-9.373 9.372-24.569 9.372-33.942 0z\"><\/path><\/svg><\/span>\n\t\t<\/span>\n\n\t\t\t\t\t\t<\/summary>\n\t\t\t\t<div role=\"region\" aria-labelledby=\"e-n-accordion-item-8638\" class=\"elementor-element elementor-element-1bdfaa45 e-con-full e-flex e-con e-child\" data-id=\"1bdfaa45\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t<div role=\"region\" aria-labelledby=\"e-n-accordion-item-8638\" class=\"elementor-element elementor-element-1473e8cd e-con-full e-flex e-con e-child\" data-id=\"1473e8cd\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t<div class=\"elementor-element elementor-element-92f74500 elementor-widget elementor-widget-heading\" data-id=\"92f74500\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">Multiplying a cell value by 260 gives a theoretical cell-only series sum. It excludes busbars, wiring, current shunts, fuses, contactors and other hardware. The source gives 46.8m\u03a9 AC or 104m\u03a9 DC for 260 nominal SHS180-314Ah cells as arithmetic illustrations, not published Energon cabinet resistance ratings.<\/p>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/details>\n\t\t\t\t\t\t<details id=\"e-n-accordion-item-8639\" class=\"e-n-accordion-item\" >\n\t\t\t\t<summary class=\"e-n-accordion-item-title\" data-accordion-index=\"10\" tabindex=\"-1\" aria-expanded=\"false\" aria-controls=\"e-n-accordion-item-8639\" >\n\t\t\t\t\t<span class='e-n-accordion-item-title-header'><div class=\"e-n-accordion-item-title-text\"> How does one high-resistance cell affect a series BESS string? <\/div><\/span>\n\t\t\t\t\t\t\t<span class='e-n-accordion-item-title-icon'>\n\t\t\t<span class='e-opened' ><svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-chevron-up\" viewBox=\"0 0 448 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M240.971 130.524l194.343 194.343c9.373 9.373 9.373 24.569 0 33.941l-22.667 22.667c-9.357 9.357-24.522 9.375-33.901.04L224 227.495 69.255 381.516c-9.379 9.335-24.544 9.317-33.901-.04l-22.667-22.667c-9.373-9.373-9.373-24.569 0-33.941L207.03 130.525c9.372-9.373 24.568-9.373 33.941-.001z\"><\/path><\/svg><\/span>\n\t\t\t<span class='e-closed'><svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-chevron-down\" viewBox=\"0 0 448 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M207.029 381.476L12.686 187.132c-9.373-9.373-9.373-24.569 0-33.941l22.667-22.667c9.357-9.357 24.522-9.375 33.901-.04L224 284.505l154.745-154.021c9.379-9.335 24.544-9.317 33.901.04l22.667 22.667c9.373 9.373 9.373 24.569 0 33.941L240.971 381.476c-9.373 9.372-24.569 9.372-33.942 0z\"><\/path><\/svg><\/span>\n\t\t<\/span>\n\n\t\t\t\t\t\t<\/summary>\n\t\t\t\t<div role=\"region\" aria-labelledby=\"e-n-accordion-item-8639\" class=\"elementor-element elementor-element-2d462e1c e-con-full e-flex e-con e-child\" data-id=\"2d462e1c\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t<div role=\"region\" aria-labelledby=\"e-n-accordion-item-8639\" class=\"elementor-element elementor-element-8811501e e-con-full e-flex e-con e-child\" data-id=\"8811501e\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t<div class=\"elementor-element elementor-element-e09a5cac elementor-widget elementor-widget-heading\" data-id=\"e09a5cac\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">One higher-resistance cell can show greater voltage sag during discharge, higher terminal voltage during charge, and more local resistive loss. It may reach a BMS limit earlier than neighboring cells, reducing usable string energy. The actual outcome also depends on capacity, SoC, temperature and balancing\u2014not resistance alone.<\/p>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/details>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-d5da41cf auto-h2 elementor-widget elementor-widget-heading\" data-id=\"d5da41cf\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Source 314Ah Cells &amp; Storage Systems from MegSolid<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-8de3b16e auto-p elementor-widget elementor-widget-heading\" data-id=\"8de3b16e\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">Lower and more uniform battery internal resistance across the cells of a high-voltage string generally helps limit resistive loss, cooling load, and capacity mismatch, although the size of any efficiency improvement must be calculated for the specific operating current, temperature, and duty cycle. MegSolid provides cell-level AC and DC resistance data for the SHS180-314Ah cell used across its 314Ah products, pack-level impedance limits for its 51.2V residential units, and project documentation for its <strong><a href=\"https:\/\/www.solidess.com\/batteries\/ci-energy-storage\/\" style=\"color:#61ce70\">liquid-cooled C&amp;I<\/a><\/strong> and utility systems.<\/p>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-dbcfea6c auto-p elementor-widget elementor-widget-heading\" data-id=\"dbcfea6c\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<p class=\"elementor-heading-title elementor-size-default\">Contact our engineering team for datasheets, test methods, and integration support:<\/p>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-f5a5b333 elementor-widget-mobile__width-inherit auto-list elementor-icon-list--layout-traditional elementor-list-item-link-full_width elementor-widget elementor-widget-icon-list\" data-id=\"f5a5b333\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"icon-list.default\">\n\t\t\t\t\t\t\t<ul class=\"elementor-icon-list-items\">\n\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item\">\n\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-circle\" viewBox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M256 8C119 8 8 119 8 256s111 248 248 248 248-111 248-248S393 8 256 8z\"><\/path><\/svg>\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text\">For 314Ah Hybrid Solid-State Cell Specifications: Review cell parameters and request resistance test documentation on our MegSolid 314Ah Hybrid Solid-State Battery page.<\/span>\n\t\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item\">\n\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-circle\" viewBox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M256 8C119 8 8 119 8 256s111 248 248 248 248-111 248-248S393 8 256 8z\"><\/path><\/svg>\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text\">For Liquid-Cooled C&amp;I and Utility Storage: Explore cabinet and container platforms on our Solid-State Energy Storage Systems hub.<\/span>\n\t\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t\t\t<\/ul>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-1574ec77 elementor-tablet-align-center elementor-align-center auto-cta elementor-widget elementor-widget-button\" data-id=\"1574ec77\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"button.default\">\n\t\t\t\t\t\t\t\t\t\t<a class=\"elementor-button elementor-button-link elementor-size-sm\" href=\"#elementor-action%3Aaction%3Dpopup%3Aopen%26settings%3DeyJpZCI6Ijk0OCIsInRvZ2dsZSI6ZmFsc2V9\">\n\t\t\t\t\t\t<span class=\"elementor-button-content-wrapper\">\n\t\t\t\t\t\t\t\t\t<span class=\"elementor-button-text\">Contact Us for a 314Ah Battery Matching and BESS Review<\/span>\n\t\t\t\t\t<\/span>\n\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"<p>Apprenez \u00e0 calculer et mesurer l\u2019ACIR vs le DCIR sur des cellules 314 Ah, \u00e9valuer la r\u00e9sistance interne acceptable, v\u00e9rifier les essais Kelvin \u00e0 quatre fils et identifier les risques de coh\u00e9rence des cha\u00eenes BESS.<\/p>","protected":false},"author":4,"featured_media":7991,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center 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