{"product_id":"nokia-7710-replacement-battery-37v-1300mah-li-ion","title":"Nokia BP-5L 7710 Replacement Battery 3.7V 1300mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eNokia 7710 \/ 770 Series — 3.7V Li-ion Replacement Battery (BP-5L)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThe BP-5L is a 3.7V, 1300mAh Li-ion cell that fits the Nokia 7710, 770, 7700, and 9500 among other compatible handsets. These mid-2000s Nokia devices share the same battery bay dimensions and connector, so one cell covers the full BP-5L family. This listing is for users whose original cell no longer holds charge through a normal day of use.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eBP-5L platform compatibility:\u003c\/strong\u003e\n    Nokia used the BP-5L across several devices that share the same 65.80 × 43.80 × 5.30mm footprint, voltage rail, and connector pinout. The BMS handshake requirements are identical across the 7710, 770, 7700, and 9500, so the cell slots in without adapter or firmware conflict.\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 7710 unit and confirmed the BMS accepted the cell on first insertion, raised no fault flags, and held voltage above 3.5V through the discharge curve without premature cutoff.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge recalibration on first use:\u003c\/strong\u003e\n    On the first cycle after installation, run the battery down to automatic shutdown and charge it back to 100% without interruption. The Nokia fuel gauge IC maps its calibration table to the new cell's discharge curve during this first full cycle — skipping it causes erratic percentage readings from day one.\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 7710 after a cell swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis happens when the fuel gauge IC is still calibrated to the old cell's discharge curve. The old cell had a steeper voltage drop at low charge, so the IC expects the same profile. When the new cell hits a load spike — screen at full brightness or a data burst — the IC reads the voltage dip as a hard cutoff threshold and kills the device. The fix is one full uninterrupted discharge cycle down to automatic shutdown, followed by a full charge. After that single cycle the coulomb counter resets against the new cell and the phantom cutoffs stop.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eNokia 7710 showing wrong battery percentage after replacement\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe Nokia 7710 stores fuel gauge calibration data tied to the previous cell's internal resistance and capacity curve. A fresh BP-5L has lower internal resistance than a degraded original, so the IC over-reports or under-reports state of charge until it gathers new data. You may see the percentage jump several points up or down without any load change. Charge to 100%, use the device until it shuts off automatically, then charge back to 100% without interruption — after this single cycle the IC recalibrates and percentage readings stabilise.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43409486676058,"sku":"BWCS-NK5LSL-1","price":23.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43409486708826,"sku":"BWCS-NK5LSL-2","price":26.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43409486741594,"sku":"BWCS-NK5LSL-3","price":28.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-NK5LSL-1.webp?v=1779579814","url":"https:\/\/batteryweb.com\/products\/nokia-7710-replacement-battery-37v-1300mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}