{"product_id":"coolpad-y91-921-replacement-battery-38v-2500mah-li-polymer","title":"Coolpad Y91-921 Replacement Battery CPLD-395 3.8V 2500mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eCoolpad Y91-921 \/ Fengshang Pro 2 — 3.8V Li-Polymer Replacement Battery (CPLD-395)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.8V, 2500mAh Li-Polymer cell replaces the original CPLD-395 battery in the Coolpad Y91-921, Fengshang Pro 2, Fengshang Pro 2 Dual SIM, and related Fengshang Pro 2 TD-LTE variants. It fits the same 78.90 × 61.50 × 3.10 mm footprint as the factory cell. Capacity is rated at 9.5Wh — identical to the OEM specification.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eFengshang Pro 2 platform compatibility:\u003c\/strong\u003e\n    All listed Fengshang Pro 2 variants — standard, Dual SIM, and TD-LTE — share the same battery bay geometry, connector pinout, and BMS handshake protocol. Swapping between these models is not required; the CPLD-395 part number covers the full set.\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 Coolpad Y91-921 unit. The BMS accepted the charge handshake on the first connection, current regulation stepped correctly at 80% state of charge, and the protection circuit tripped at the expected undervoltage 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 for one complete discharge-charge cycle. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging begins — skipping this step causes the percentage counter to read incorrectly 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\"\u003eSudden shutdown at 20–30% on the Coolpad Y91-921\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThis is a voltage cliff, not a capacity problem. When the modem transmits at full power or the screen runs at peak brightness, the cell must sustain high current draw. An aged or deeply discharged cell cannot hold its terminal voltage under that load, so the protection circuit cuts output even though the fuel gauge still shows charge remaining. The replacement cell restores the voltage headroom the modem needs. If shutdowns persist after fitting the new cell, charge to 100% and run one full discharge cycle so the coulomb counter resets its endpoint calibration.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003ePhone not powering on after the battery sat in storage\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eLi-Polymer cells left uncharged for extended periods can drop below 2.5V per cell, which triggers BMS lockout — the circuit physically disconnects output to prevent damage. The phone shows no response to the power button and no charge indicator on the screen. Connect the phone to a wall adapter, not a PC USB port, and leave it undisturbed for 15–20 minutes before attempting to power on. If the BMS recovers, the charge LED will activate; at that point, allow a full charge to 3.8V before normal use.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43392078807130,"sku":"BWCS-CPY921SL-1","price":26.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43392078839898,"sku":"BWCS-CPY921SL-2","price":29.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43392078872666,"sku":"BWCS-CPY921SL-3","price":32.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-CPY921SL-1.webp?v=1779143620","url":"https:\/\/batteryweb.com\/products\/coolpad-y91-921-replacement-battery-38v-2500mah-li-polymer","provider":"BatteryWeb","version":"1.0","type":"link"}