{"product_id":"myphone-replacement-battery-37v-900mah-li-ion","title":"MyPhone MP-S-A2 Replacement Battery 3.7V 900mAh Li-ion","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eMyPhone MP-S-A2 — 3.7V Li-ion Replacement Battery\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.7V, 900mAh Li-ion cell replacing the OEM MP-S-A2 battery in compatible MyPhone smartphones. It measures 53.00 × 34.00 × 4.80mm and delivers 3.33Wh of capacity. If your phone is shutting down early, failing to charge, or the original cell has swollen, this is the direct swap.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eMyPhone MP-S-A2 platform fit:\u003c\/strong\u003e\n    The MP-S-A2 cell is shared across several MyPhone handsets that use the same battery bay dimensions and connector pinout. Voltage rail at 3.7V nominal matches the charge IC spec on these boards, so the BMS handshake completes without error codes.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell through a full charge-discharge sequence and confirmed the BMS protection circuit trips correctly at both ends — low-voltage cutoff activated cleanly below 2.75V, and the overcharge threshold held at 4.2V without deviation.\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 recalibrate against the new cell's discharge curve before high-current charging pushes current into 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 MyPhone reports wrong battery percentage after a cell swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe fuel gauge IC on MyPhone handsets uses a coulomb counter calibrated to the original cell's internal resistance and discharge curve. A new cell has different characteristics, so the IC's stored model no longer matches actual cell behaviour. The phone may show 100% then drop rapidly, or stall at a fixed percentage for an extended period. One full uninterrupted discharge down to auto-shutdown, followed by a complete charge to 100%, forces the coulomb counter to rebuild its reference table against the new cell.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eSudden shutdown at 20–30% remaining on the replacement cell\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis happens when the modem radio or display fires a high-current draw and the cell voltage dips below the BMS cutoff threshold before the fuel gauge expects it. The reported percentage looks safe, but the cell's actual voltage under load has already hit the floor. It is not a defective cell — it is the fuel gauge IC still running on the old cell's discharge model. Run one full cycle as described above and the shutdowns will stop once the IC recalibrates its voltage-to-percentage mapping.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43405023248474,"sku":"BWCS-NK4CHL-1","price":22.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43405023281242,"sku":"BWCS-NK4CHL-2","price":25.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43405023314010,"sku":"BWCS-NK4CHL-3","price":27.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-NK4CHL-1.webp?v=1779369842","url":"https:\/\/batteryweb.com\/products\/myphone-replacement-battery-37v-900mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}