{"product_id":"toshiba-satellite-5105-s501-replacement-battery-108v-4400mah-li-ion","title":"Toshiba Satellite 5105-S501 PA3123U-1BRS Replacement Battery 10.8V","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eToshiba Satellite 5105-S501 — 10.8V Li-ion Replacement Battery (PA3123U-1BRS)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 10.8V, 4400mAh Li-ion replacement battery for the Toshiba Satellite 5105-S501 and the broader Satellite 5000\/5100\/5105 series. It cross-references OEM part numbers PA3123U-1BRS, PA3178U-1BRS, PA3211U-1BRS, PABAS018, and several others listed in the compatibility data. The cell fits directly into the battery bay of these late-era Pentium 4-M Satellite notebooks.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eSatellite 5000\/5100\/5105 series fit:\u003c\/strong\u003e\n    These models share the same 10.8V three-cell-series architecture, battery bay dimensions, and connector pinout. The BMS communication protocol is also common across this generation, so one cell SKU covers the full range without modification.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell through charge, discharge, and a simulated CPU-plus-display load spike. The BMS held the charge rail steady at 10.8V nominal and tripped thermal protection correctly at threshold — no premature cutoff under sustained load.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-install discharge cycle on the Satellite 5100 series:\u003c\/strong\u003e\n    After fitting this battery, run one full discharge to hibernate-cutoff, then charge uninterrupted to 100%. This resets the BIOS battery learn cycle on these Toshiba units and clears the inaccurate health warning that appears after every cell swap.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the Satellite 5105 BIOS reports poor battery health immediately after swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe Satellite 5000\/5100\/5105 series stores battery health data in EEPROM on the battery's own BMS board. When you fit a new cell, the BIOS reads that EEPROM and compares it against the laptop's stored charge history — the mismatch flags as \"poor health\" or displays a degraded percentage. This is not a fault with the replacement cell. One full discharge-to-hibernate followed by a full uninterrupted charge gives the BIOS enough cycle data to recalibrate its health register. Most units clear the warning after two full cycles.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eSatellite 5105 shutting down at 20–30% battery remaining\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis happens when the cell voltage drops below the minimum threshold under combined CPU and display load — even though the fuel gauge still shows charge remaining. The Satellite 5100-series power controller shuts the system down the moment the pack drops below roughly 9.9V under load, which can happen well before the gauge reads zero. A degraded or partially cycled new cell is the most common cause. Confirm the pack voltage under load with a battery diagnostic — if the pack reads below 10.4V at 50% state of charge, the cells need conditioning or the unit is defective.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43410874564698,"sku":"BWCS-TO5100-1","price":57.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43410874597466,"sku":"BWCS-TO5100-2","price":67.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43410874630234,"sku":"BWCS-TO5100-3","price":74.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-TO5100-1.webp?v=1779581443","url":"https:\/\/batteryweb.com\/products\/toshiba-satellite-5105-s501-replacement-battery-108v-4400mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}