{"product_id":"bea-fon-s30-replacement-battery-37v-950mah-li-ion","title":"Bea-fon S30 Replacement Battery 3.7V 950mAh Li-ion","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eBea-fon S30 \/ S31 Series — 3.7V Li-ion Replacement Battery\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.7V, 950mAh Li-ion cell replaces the original battery in the Bea-fon S30, S31, and S31 EU001B mobile phones. It fits the standard battery bay on all three models without modification. Capacity figures come from the product data: 950mAh \/ 3.52Wh.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eS30 \/ S31 \/ S31 EU001B shared battery platform:\u003c\/strong\u003e\n    All three models use the same battery bay dimensions, voltage rail, and connector pinout. Bea-fon carried the same cell specification across this series, so one replacement covers all three variants without adapters or wiring changes.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell through full charge and discharge passes, monitoring the BMS cutoff at the low-voltage threshold. The protection circuit tripped correctly at the undervoltage limit and resumed charge acceptance without manual reset.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge recalibration on first cycle:\u003c\/strong\u003e\n    On first use after installation, run one complete discharge down to automatic shutdown, then charge uninterrupted to 100% before resuming normal use. This gives the fuel gauge IC a full reference curve against the new cell — skipping it causes the percentage counter to drift against the new cell's actual discharge profile.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the S30 reports wrong battery percentage after a cell swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe S30 uses a fuel gauge IC that builds its charge estimate from the previous cell's discharge curve stored in memory. When a new cell goes in, that stored curve no longer matches the actual voltage-to-capacity relationship of the replacement. The IC reads voltage correctly but maps it to the wrong percentage. One full discharge-to-shutdown followed by an uninterrupted charge forces the IC to rewrite the reference curve against the new cell's actual behaviour.\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 load — voice calls, screen-on data, or GPS — before the displayed percentage reaches zero. The fuel gauge IC predicts remaining charge from a static curve, but under high current draw the cell voltage sags faster than the model expects and the protection circuit cuts power. It is not a faulty battery; it is the IC still working from an uncalibrated curve. Run two full discharge-charge cycles and the shutdowns should stop. If they persist past two cycles, check that the battery contacts in the bay are clean and seated flat against the cell pads.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43409483858010,"sku":"BWCS-NK5FSL-1","price":22.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43409483890778,"sku":"BWCS-NK5FSL-2","price":25.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43409483923546,"sku":"BWCS-NK5FSL-3","price":27.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-NK5FSL-1.webp?v=1779579814","url":"https:\/\/batteryweb.com\/products\/bea-fon-s30-replacement-battery-37v-950mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}