{"product_id":"asus-u20-replacement-battery-111v-4400mah-li-ion","title":"A31-U20 Asus U20 Replacement Battery 11.1V 4400mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eAsus U20 \/ U50 \/ U80 Series — 11.1V Li-ion Replacement Battery (A31-U20)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 11.1V, 4400mAh (48.84Wh) Li-ion battery replaces the original cell in the Asus U20, U20A, U50, U80, and related ultraportable notebook series. It covers OEM part numbers A31-U20, A32-U20, A32-U50, A33-U50, and several others listed above. Drop it in when the original cell no longer holds a charge or the system reports degraded health.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eU20 \/ U50 \/ U80 platform fit:\u003c\/strong\u003e\n    These models share the same 11.1V three-cell architecture, connector pinout, and BMS communication protocol — which is why one cell covers the full range. Voltage rail and thermistor wiring match across all variants listed.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell through full charge and discharge cycles on a U20A unit. The BMS handshake completed on first connection, charge acceptance was normal from empty to full, and the protection circuit tripped correctly at the low-voltage cutoff threshold.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-install calibration on the U20:\u003c\/strong\u003e\n    After fitting, run the battery down until the laptop hibernates at near-zero, then charge uninterrupted to 100%. This forces the BIOS battery learn cycle to reset against the new cell and clears the inaccurate health warning that almost always appears after a 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 U20 BIOS reports poor battery health immediately after a cell swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe U20 stores battery health data in EEPROM on the original cell. When a new cell goes in, the BIOS reads stale cycle count and capacity data left over from the old pack and flags the battery as degraded before a single charge has completed. This is not a fault with the replacement cell — it is a data mismatch. One full discharge-to-hibernate followed by an uninterrupted charge to 100% resets the learn cycle. After two to three calibration cycles, the reported health figure normalises.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eU20 shutting down at 20–30% remaining shown on the gauge\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 actual discharge curve. The gauge inherited calibration data from the old, degraded pack — so it misreads the voltage cliff on the new cell and triggers shutdown earlier than the true empty point. It is not a defective battery. Run two to three complete discharge-to-hibernate and full recharge cycles without interrupting the charge. After calibration, the cutoff point shifts back to the correct low-voltage threshold near 10.5V per cell group.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43410798542938,"sku":"BWCS-AUA31NB-1","price":98.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43410798575706,"sku":"BWCS-AUA31NB-2","price":111.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43410798608474,"sku":"BWCS-AUA31NB-3","price":121.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-AUA31NB-1.webp?v=1779581141","url":"https:\/\/batteryweb.com\/products\/asus-u20-replacement-battery-111v-4400mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}