{"product_id":"билайн-dual-replacement-battery-37v-800mah-li-ion","title":"Билайн Dual 3.7V 800mAh Li-ion Replacement Battery","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eБилайн Dual — 3.7V Li-ion Replacement Battery\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.7V, 800mAh Li-ion cell replaces the original battery in the Билайн Dual smartphone. The Dual is a compact dual-SIM handset, and this battery restores power to units where the original cell has degraded or failed. Capacity figures come from the product specification — 800mAh, 2.96Wh.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eБилайн Dual compatibility:\u003c\/strong\u003e\n    The Dual uses a straightforward removable Li-ion cell with no proprietary BMS handshake — the phone's charge IC communicates directly with the cell through standard contacts. No firmware pairing is required, so a correctly specced replacement cell seats and registers without rejection.\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 the bench, monitoring voltage response at the terminals. The BMS held stable cutoff behaviour at the low-voltage threshold, and charge acceptance was consistent across repeated cycles.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge recalibration on first use:\u003c\/strong\u003e\n    On first use after installation, run one complete discharge-to-charge cycle with fast charging disabled. The phone's fuel gauge IC is still calibrated to the old cell's discharge curve — one full cycle against the new cell lets it remap correctly before you rely on the percentage readout.\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 Билайн Dual after a cell swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThis is a voltage cliff problem, not a capacity problem. Under combined load from both SIM radios and the screen, the new cell's terminal voltage drops faster than the fuel gauge IC expects — the phone reads 25% but the cell is already near its cutoff threshold. The charge IC then trips the shutdown to protect the cell. One full slow discharge-charge cycle lets the coulomb counter recalibrate its end-of-discharge voltage model to match the new cell, and the shutdowns stop.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eБилайн Dual not powering on after the replacement cell sat in storage\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eLi-ion cells self-discharge in storage, and if the replacement battery dropped below approximately 2.5V per cell before installation, the BMS enters lockout to prevent damage from charging a deeply discharged cell. The phone will show no response — no boot, no charge indicator. Connect to a charger and leave it for 15–20 minutes without attempting to power on; most charge ICs on this class of device include a trickle pre-charge stage that slowly recovers the cell voltage to the point where the BMS re-enables normal charge current. If the charge LED comes on within that window, the cell is recovering — let it reach 3.0V before booting.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43405100482650,"sku":"BWCS-OT880SL-1","price":27.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43405100515418,"sku":"BWCS-OT880SL-2","price":31.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43405100548186,"sku":"BWCS-OT880SL-3","price":33.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-OT880SL-1.webp?v=1779369970","url":"https:\/\/batteryweb.com\/products\/%d0%b1%d0%b8%d0%bb%d0%b0%d0%b9%d0%bd-dual-replacement-battery-37v-800mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}