{"product_id":"kyocera-replacement-battery-37v-650mah-li-ion","title":"Kyocera KY003UAA Replacement Battery 3.7V 650mAh Li-ion","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eKyocera KY003UAA — 3.7V Li-ion Replacement Battery\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.7V, 650mAh Li-ion cell built to replace the KY003UAA battery in compatible Kyocera smartphones. The original cell degrades over charge cycles, causing the phone to shut down early or refuse to charge. Swapping in a fresh cell restores normal voltage output and charge acceptance.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eKY003UAA platform fit:\u003c\/strong\u003e\n    Kyocera phones using this part number share the same 3.7V single-cell architecture, connector pinout, and BMS handshake requirements. The replacement cell matches those electrical parameters so the charge IC recognises the battery correctly on boot.\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 under load. The BMS engaged protection cutoffs at the correct low-voltage threshold, and the charge IC accepted a full charge cycle without fault flags.\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 for one complete discharge-charge cycle. This lets the fuel gauge IC map its coulomb counter against the new cell's actual discharge curve before high-current charging begins on an uncalibrated cell.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the phone reports wrong battery percentage after a cell swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe fuel gauge IC stores a learned discharge curve from the old cell. When a new cell goes in, that stored curve no longer matches reality — so the percentage reading drifts or jumps. Run one full discharge down to automatic shutdown, then charge uninterrupted to 100% without removing the cable. After that single calibration cycle, the coulomb counter resets its reference points against the new cell and percentage readings stabilise.\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 happens when the cell voltage drops sharply under the load spike from the modem radio or display backlight — a voltage cliff the gauge IC did not predict. The phone's cutoff circuit sees the instantaneous voltage drop below the safe threshold and trips before the displayed percentage reaches zero. It is not a faulty cell — it is an uncalibrated gauge reading a mismatch between stored curve and actual cell impedance. Complete one full calibration cycle and verify the phone holds voltage above 3.4V under screen-on load.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43405117063258,"sku":"BWCS-KSA001SL-1","price":23.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43405117096026,"sku":"BWCS-KSA001SL-2","price":26.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43405117128794,"sku":"BWCS-KSA001SL-3","price":28.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-KSA001SL-1.webp?v=1779369992","url":"https:\/\/batteryweb.com\/products\/kyocera-replacement-battery-37v-650mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}