{"product_id":"htc-ace-replacement-battery-37v-1050mah-li-ion","title":"HTC Ace Replacement Battery BA S470 3.7V 1050mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eHTC Desire HD \/ Ace — 3.7V Li-ion Replacement Battery (BA S470)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.7V, 1050mAh Li-ion replacement battery for the HTC Ace and Desire HD family of Android smartphones. It also fits the A9191 and Surround variants that share the same battery bay and connector. Capacity is 1050mAh (3.89Wh), matching original spec.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eAce and Desire HD platform compatibility:\u003c\/strong\u003e\n    These models share the same physical footprint, connector pinout, and BMS handshake protocol — the BA S470 part number 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 and discharge cycles on a Desire HD unit. The BMS accepted charge from a stock HTC charger without fault codes, and protection circuitry tripped correctly at low-voltage cutoff.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge recalibration on first use:\u003c\/strong\u003e\n    On first installation, run one complete discharge to automatic shutdown, then charge uninterrupted to 100% before use. This gives the phone's fuel gauge IC a full reference curve against the new cell — skipping this step causes erratic percentage readings for the first several cycles.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the Desire HD reports wrong battery percentage after a cell swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe Desire HD uses a coulomb counter and learned discharge curve stored against the old cell. When a new cell goes in, that stored curve no longer matches the actual voltage-to-capacity relationship of the replacement. The phone reads voltage, maps it to the old curve, and outputs an inaccurate percentage. One full discharge-to-shutdown followed by an uninterrupted charge forces the fuel gauge IC to relearn the curve against the new cell's chemistry. After that cycle, percentage accuracy returns to normal.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eSudden shutdown at 20–30% on the replacement cell\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis is a voltage cliff, not a capacity fault. Under modem radio or display load, the cell voltage drops sharply below the threshold the BMS will sustain — even if the fuel gauge still shows charge remaining. It happens most often when the fuel gauge IC hasn't completed recalibration. Run one full discharge cycle and let the phone shut off on its own. If shutdowns persist past two full cycles, check that resting voltage sits above 3.6V after a full charge using a multimeter on the battery terminals.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43405110444122,"sku":"BWCS-HT9191SL-1","price":22.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43405110476890,"sku":"BWCS-HT9191SL-2","price":25.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43405110509658,"sku":"BWCS-HT9191SL-3","price":27.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-HT9191SL-1.webp?v=1779369992","url":"https:\/\/batteryweb.com\/products\/htc-ace-replacement-battery-37v-1050mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}