{"product_id":"asus-vivobook-s551l-replacement-battery-111v-4500mah-li-polymer","title":"C31-S551 Asus VivoBook S551L Replacement Battery 11.1V 4500mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eAsus VivoBook S551L Series — 11.1V Li-Polymer Replacement Battery (C31-S551)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 11.1V, 4500mAh Li-Polymer battery replaces the OEM C31-S551 cell in the Asus VivoBook S551L, S551LA, and S551LB notebooks. It fits the ultrabook-style chassis without modification and connects via the original three-cell connector. Capacity is 4500mAh (49.95Wh) — matching the stock specification.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eS551L platform fit:\u003c\/strong\u003e\n    The S551L, S551LA, and S551LB share the same 11.1V three-cell Li-Polymer architecture, connector pinout, and BMS handshake protocol. One cell covers all three variants because the voltage rail and communication interface are identical across the platform.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell through full charge and discharge on the S551LB platform. The BMS negotiated correctly with the ASUS EC firmware — no charging errors, no ACPI fault codes, and the fuel gauge updated continuously through each cycle.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-install calibration for the S551L:\u003c\/strong\u003e\n    After fitting this cell, run the laptop down to hibernate cutoff under normal use — screen on, applications running — then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears after every cell swap on this platform.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the S551L BIOS reports poor battery health after a cell swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe S551L stores capacity history and cycle count data in the battery's EEPROM. When a new cell goes in, that EEPROM is blank or carries factory defaults the BIOS does not recognise as current. The embedded controller reads this as a degraded or unknown cell and flags poor health immediately. Running one full discharge-to-hibernate then an uninterrupted full charge writes new baseline data to the EEPROM and clears the flag. After two to three cycles the health reading stabilises to accurate.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eLaptop shuts down at 20–30% charge shown on the S551L\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis happens when the fuel gauge IC has not yet calibrated against the new cell's voltage curve. The old cell's curve is still cached, so the OS shows 25% while the actual cell voltage has already dropped below the safe cutoff threshold under CPU and display load. The laptop shuts down to protect the cell — not because the battery is faulty. Run two full discharge-to-hibernate cycles followed by uninterrupted full charges, and the fuel gauge IC recalibrates to the new cell. The cutoff point drops back to below 5% reported charge.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43409776574554,"sku":"BWCS-AUS551NB-1","price":75.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43409776607322,"sku":"BWCS-AUS551NB-2","price":87.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43409776640090,"sku":"BWCS-AUS551NB-3","price":97.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-AUS551NB-1.webp?v=1779580818","url":"https:\/\/batteryweb.com\/products\/asus-vivobook-s551l-replacement-battery-111v-4500mah-li-polymer","provider":"BatteryWeb","version":"1.0","type":"link"}