{"product_id":"lenovo-s820-replacement-battery-37v-2000mah-li-ion","title":"Lenovo BL210 S820 Replacement Battery 3.7V 2000mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eLenovo S820 \/ A770E Series — 3.7V Li-ion Replacement Battery (BL210)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.7V, 2000mAh Li-ion replacement cell for the Lenovo S820, S820e, A750e, and A770E smartphones. It slots into the original battery bay and connects via the existing ribbon contact. Use the capacity figure above — 2000mAh — as the reference spec for this cell.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eS820 and A-series compatibility:\u003c\/strong\u003e\n    The S820, S820e, A750e, and A770E all share the same battery bay dimensions, contact pitch, and 3.7V supply rail. The BL210 part number covers this group because the BMS handshake and connector pinout are identical across these models.\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 monitored rig. The BMS held charge cutoff at 4.2V and triggered low-voltage protection at 3.0V. No thermal spike was recorded during the first full charge.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge recalibration on first use:\u003c\/strong\u003e\n    After fitting this cell, disable fast charging and run one complete discharge down to automatic shutdown, then charge to 100% uninterrupted. This gives the fuel gauge IC one clean reference cycle against the new cell's discharge curve before fast charge current is applied.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the S820 reports wrong battery percentage after a cell swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe S820 uses a coulomb-counting fuel gauge IC that builds its percentage model against the previous cell's charge curve. When a new cell goes in, that stored curve no longer matches. The gauge reads an offset voltage and maps it to the wrong state-of-charge point. One full discharge-to-shutdown and uninterrupted recharge to 100% resets the reference table. After that cycle, percentage reporting stabilises.\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 or display triggers a load spike and the cell voltage drops below the BMS cutoff threshold — even though the gauge still shows charge remaining. It is a voltage-cliff issue, not a capacity issue. The BMS sees the instantaneous sag past 3.0V and shuts the device down as a protection measure. Run the fuel gauge recalibration cycle first; if shutdowns continue past that point, check that the battery contact pins on the motherboard are clean and making full contact.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43404261720154,"sku":"BWCS-LVS820SL-1","price":24.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43404261752922,"sku":"BWCS-LVS820SL-2","price":27.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43404261785690,"sku":"BWCS-LVS820SL-3","price":30.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-LVS820SL-1.webp?v=1779369511","url":"https:\/\/batteryweb.com\/products\/lenovo-s820-replacement-battery-37v-2000mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}