{"product_id":"navon-mizu-bt-70-replacement-battery-37v-1200mah-li-ion","title":"Navon Mizu BT70 3.7V Replacement Battery 1200mAh Li-ion","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eNavon Mizu BT-70 — 3.7V Li-ion Replacement Battery (BT70)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.7V, 1200mAh Li-ion cell is a direct replacement for the Navon Mizu BT-70 and Mizu BT70 smartphones. It slots into the original battery bay and connects to the same three-contact board the phone's charge IC expects. Capacity is 1200mAh (4.44Wh), matching the factory specification.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eMizu BT-70 and BT70 fit:\u003c\/strong\u003e\n    Both model designations use the same physical cell format, connector pitch, and BMS handshake. One cell covers both variants without modification.\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 bench rig, confirmed the BMS accepted the charge IC handshake correctly, and verified cell voltage held stable under a simulated screen-plus-modem load.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge recalibration on first use:\u003c\/strong\u003e\n    After installation, disable fast charging and run one full discharge-charge cycle at standard rate. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging pushes current into an uncalibrated cell — skipping this step causes 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\"\u003eWhy the Mizu BT-70 reports wrong battery percentage after a cell swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe Mizu BT-70 uses a fuel gauge IC that learns the battery's discharge curve over cycles. When a new cell goes in, the IC still holds the old cell's calibration data. The percentage shown on screen is calculated against a curve that no longer matches the physical cell. One full discharge to automatic shutdown followed by a full charge at standard rate resets this — after that cycle, percentage accuracy returns to normal.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eSudden shutdown at 20–30% remaining on the Mizu BT-70\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis happens when the cell voltage drops below the BMS cutoff threshold under the combined load of the modem radio and display — even though the fuel gauge still shows charge remaining. Older or deeply discharged cells hit this voltage cliff faster. On a new replacement cell, this symptom typically appears if the fuel gauge IC hasn't yet recalibrated. Run one full cycle at standard charge rate; if shutdown still occurs below 3.5V under load, the BMS cutoff voltage is doing its job and the cell is within normal parameters.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43405044252762,"sku":"BWCS-DEP330SL-1","price":23.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43405044285530,"sku":"BWCS-DEP330SL-2","price":26.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43405044318298,"sku":"BWCS-DEP330SL-3","price":28.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-DEP330SL-1.webp?v=1779369842","url":"https:\/\/batteryweb.com\/products\/navon-mizu-bt-70-replacement-battery-37v-1200mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}