{"product_id":"lenovo-a706-replacement-battery-37v-1350mah-li-ion","title":"Lenovo BL209 A706 Replacement Battery 3.7V 1350mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eLenovo A706 \/ A516 Series — 3.7V Li-ion Replacement Battery (BL209)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.7V, 1350mAh Li-ion cell replacing the OEM BL209 battery in Lenovo A706, A820E, A516, and A398T smartphones. It fits the original battery bay without modification and uses the same three-contact connector. Voltage and physical dimensions match OEM spec exactly.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eA706 \/ A516 platform compatibility:\u003c\/strong\u003e\n    These models share the same 3.7V single-cell architecture, identical connector pitch, and the same fuel gauge IC communication protocol — which is why one BL209 cell covers all listed variants without adapter or wiring change.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell on a Lenovo A706 unit and confirmed the BMS accepted the handshake on first boot, charge termination triggered correctly at 4.2V, and the protection circuit tripped as expected on simulated over-discharge at 2.75V.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge recalibration on first cycle:\u003c\/strong\u003e\n    After fitting the new cell, run one full discharge down to auto-shutdown, then charge uninterrupted to 100% before normal use — the A706's fuel gauge IC maps its SoC curve against the first complete cycle, and skipping this step causes percentage drift or erratic jumps in subsequent sessions.\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 A706 after a cell swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe A706 uses a coulomb-counter-based fuel gauge that was calibrated to the original cell's internal resistance profile. A new cell has lower impedance, so the gauge underestimates how close the cell actually is to its lower voltage cutoff. Under heavy load — mobile data, screen-on, or a call — current draw spikes and terminal voltage drops faster than the gauge expects, triggering an emergency shutdown even though the displayed percentage reads 20–30%. The fix is a full discharge-to-shutdown and uninterrupted recharge cycle. After that single cycle, the gauge recalibrates its SoC endpoints against the new cell and the shutdowns stop.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eDevice won't power on after the BL209 sat discharged in storage\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eLi-ion cells left in storage below roughly 2.5V trip the BMS protection circuit into a hard lockout — the pack reads zero voltage at the contacts and the phone shows nothing on screen. Plugging in a standard charger often doesn't recover it because the phone's charge IC refuses to start a charge cycle when it detects no cell voltage. Connect the phone to a known-good USB charger and leave it for 15–20 minutes without pressing any button — most BL209-compatible BMS circuits include a trickle pre-charge path that slowly brings the cell back above the 2.9V threshold before the main charge IC takes over. If the screen still shows nothing after 20 minutes, try a different cable before assuming the cell is unrecoverable.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43404290424922,"sku":"BWCS-LVA378SL-1","price":23.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43404290457690,"sku":"BWCS-LVA378SL-2","price":26.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43404290490458,"sku":"BWCS-LVA378SL-3","price":29.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-LVA378SL-1.webp?v=1779369657","url":"https:\/\/batteryweb.com\/products\/lenovo-a706-replacement-battery-37v-1350mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}