{"product_id":"htc-one-a9-replacement-battery-385v-2100mah-li-polymer","title":"B2PQ9100 HTC One A9 Replacement Battery 3.85V 2100mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eHTC One A9 — 3.85V Li-Polymer Replacement Battery (B2PQ9100)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.85V, 2100mAh lithium-polymer cell replaces the original battery in the HTC One A9, One A9 LTE, and Hima Aero smartphones. It matches OEM part numbers B2PQ9100 and 35H00252-00M. Capacity figure is sourced from the product specification — 8.09Wh total energy.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eOne A9 and Hima Aero platform fit:\u003c\/strong\u003e\n    These models share the same 3.85V battery rail, connector pinout, and BMS handshake protocol, which is why one cell covers the full variant range including the 2PQ9120 chassis.\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 the One A9 platform. The BMS accepted the cell without error flags, and the charge IC completed a full constant-current to constant-voltage transition at the correct cutoff threshold.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge recalibration on first use:\u003c\/strong\u003e\n    On first use after installation, disable fast charging and run one complete discharge-charge cycle. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging pushes current into an uncalibrated cell — preventing erratic percentage readings early on.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eSudden shutdown at 20–30% on a replacement cell\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis is a voltage cliff failure. The fuel gauge IC still holds calibration data from the old, degraded cell, so it reads the new cell's state-of-charge incorrectly. When modem transmit bursts or screen brightness spikes draw peak current, the cell voltage briefly dips below the BMS cutoff threshold — even though the gauge shows charge remaining. One full discharge-charge cycle forces the coulomb counter to re-anchor to the new cell's actual chemistry. After that cycle, shutdowns at false-high percentages typically stop.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eDevice not powering on after the battery sat in storage\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eLithium-polymer cells self-discharge in storage. If the cell drops below approximately 2.5V, the BMS enters lockout to prevent damage — and the phone will not respond to a normal charger connection. Connect the device to a wall adapter, not a PC USB port, and leave it for 20–30 minutes without attempting to power it on. The charge IC on the One A9 runs a trickle pre-charge sequence that slowly brings the cell back above the BMS reactivation threshold, typically around 2.9V, before switching to normal charge current.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43392104759386,"sku":"BWCS-HTA900SL-1","price":24.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43392104792154,"sku":"BWCS-HTA900SL-2","price":27.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43392104824922,"sku":"BWCS-HTA900SL-3","price":30.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-HTA900SL-1.webp?v=1779143796","url":"https:\/\/batteryweb.com\/products\/htc-one-a9-replacement-battery-385v-2100mah-li-polymer","provider":"BatteryWeb","version":"1.0","type":"link"}