{"product_id":"nokia-301-replacement-battery-37v-1200mah-li-ion","title":"Nokia BL-4U Replacement Battery 3.7V 1200mAh Li-ion","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eNokia 301 \/ 500 \/ 515 Series — 3.7V Li-ion Replacement Battery (BL-4U)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.7V, 1200mAh Li-ion replacement for the Nokia BL-4U battery. It fits the Nokia 301, 301-1, 500, 515, and over 19 additional Nokia feature phone models that share the same BL-4U footprint and connector. Capacity is rated at 4.44Wh, matching the original Nokia specification.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eBL-4U platform compatibility:\u003c\/strong\u003e\n    These Nokia models share a common 3.7V single-cell architecture, identical connector pinout, and the same BMS handshake protocol — which is why one cell revision covers all of them without modification.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell on a Nokia 301 and monitored BMS cutoff at both ends of the charge curve. The protection circuit tripped correctly at the low-voltage threshold, and charge termination fired at 4.2V as expected.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge recalibration on first install:\u003c\/strong\u003e\n    After fitting this cell, run one full discharge down to auto-shutdown, then charge uninterrupted to 100% before normal use. The Nokia fuel gauge IC is calibrated to the old cell's discharge curve — one complete cycle rewrites the reference and stops erratic percentage readings.\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 replacement cell\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe Nokia 301 fuel gauge IC stores a discharge curve from the previous cell. A new cell with a slightly different internal resistance profile hits a voltage point the IC doesn't recognise as safe — it cuts power even though charge remains. This isn't a faulty cell; it's a calibration mismatch between the new chemistry and the stored reference. Run one full discharge-to-shutdown cycle followed by a complete uninterrupted charge, and the IC rewrites its cutoff threshold to match the new cell's actual 3.0V floor.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003ePhone reports wrong battery percentage after cell swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eNokia's fuel gauge IC uses a coulomb counter anchored to a learned capacity value from the original cell. Swapping cells doesn't reset that stored value, so the percentage readout drifts — it may read 50% and shut down, or read 20% with significant charge still available. The fix is the same full-cycle recalibration: discharge completely to auto-off, then charge to 100% in one session without interruption. After that cycle, the coulomb counter reanchors to the new cell's actual capacity and percentage accuracy stabilises.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43405019086938,"sku":"BWCS-NK4UXL-1","price":22.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43405019119706,"sku":"BWCS-NK4UXL-2","price":25.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43405019152474,"sku":"BWCS-NK4UXL-3","price":27.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-NK4UXL-1.webp?v=1779369842","url":"https:\/\/batteryweb.com\/products\/nokia-301-replacement-battery-37v-1200mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}