{"product_id":"asus-vivobook-4000-replacement-battery-76v-4700mah-li-polymer","title":"Asus VivoBook 4000 Compatible Battery C21N1408 7.6V 4700mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eAsus VivoBook V555L \/ MX555 \/ 4000 Series — 7.6V Li-Polymer Replacement Battery (C21N1408)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 7.6V, 4700mAh (35.72Wh) Li-Polymer replacement battery for the Asus VivoBook 4000, V555L, MX555, A555LJ, and related models. It replaces OEM part numbers C21N1408, 0B200-01130100, and 0B200-01130300. If your VivoBook no longer holds a charge or powers off unexpectedly, this cell is the direct swap.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eVivoBook V555 \/ MX555 \/ 4000 platform fit:\u003c\/strong\u003e\n    These models share the same two-cell Li-Polymer pack format, 7.6V nominal voltage rail, and connector pinout. The BMS handshake protocol is consistent across this generation, so the replacement cell is recognised without any firmware workaround.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell through charge and discharge on a VivoBook V555L unit. The BMS accepted the new cell without fault codes, and the protection circuit responded correctly to overcharge and over-discharge cutoff thresholds.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFirst-cycle calibration after install:\u003c\/strong\u003e\n    After fitting this cell, run a full discharge to the hibernate cutoff point, then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears after swapping cells 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\"\u003eBIOS reporting poor battery health after fitting a new C21N1408 cell\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eWhen a new cell goes in, the BIOS still holds EEPROM data from the old pack — cycle count, learned capacity, and health flags. The system compares the new cell's output against stale reference values and flags it as degraded before it has been through a single cycle. This is not a fault with the replacement cell. Run one complete discharge-to-hibernate followed by a full uninterrupted charge, and the BIOS will rewrite those values against the new cell's actual behaviour.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eVivoBook shutting down at 20–30% charge shown on screen\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe fuel gauge IC calibrates against cell behaviour over several cycles. After a swap, the IC is still working from the old cell's discharge curve, so it misreads the remaining capacity. When the new cell hits a voltage the IC hasn't mapped yet, the system interprets it as empty and cuts power — even though the percentage shown still reads 20–30%. The fix is two to three full discharge-and-charge cycles so the IC relearns the curve. After calibration, shutdowns should stop above 5% and the percentage readout will track accurately. Confirm calibration is complete when the laptop reaches hibernate at a consistent voltage near 6.8V per cell.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43410733662298,"sku":"BWCS-AUV555NB-1","price":58.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43410733695066,"sku":"BWCS-AUV555NB-2","price":68.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43410733727834,"sku":"BWCS-AUV555NB-3","price":75.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-AUV555NB-1.webp?v=1779580453","url":"https:\/\/batteryweb.com\/products\/asus-vivobook-4000-replacement-battery-76v-4700mah-li-polymer","provider":"BatteryWeb","version":"1.0","type":"link"}