{"product_id":"avantree-sp850-replacement-battery-37v-1200mah-li-ion","title":"Avantree SP850 Replacement Battery 3.7V 1200mAh Li-ion","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eAvantree SP850 — 3.7V Li-ion Replacement Battery\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.7V, 1200mAh Li-ion replacement battery for the Avantree SP850 portable Bluetooth speaker. It slots in when the original cell degrades and can no longer hold a useful charge. Dimensions are 53.00 × 33.90 × 5.70mm — confirm these against your existing cell before ordering.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eSP850 fit notes:\u003c\/strong\u003e\n    The SP850 runs a single-cell 3.7V Li-ion configuration. This cell matches the original voltage rail and physical footprint. The BMS on the speaker board manages charge termination and low-voltage cutoff, so the replacement cell needs to match nominal voltage exactly — this one does.\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. The BMS accepted the cell cleanly, reached full charge termination at 4.2V, and low-voltage cutoff triggered before the cell dropped below 3.0V under load.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFirst-cycle recalibration on the SP850:\u003c\/strong\u003e\n    After fitting this cell, run one full discharge down to auto-shutoff, then charge uninterrupted to 100% before use. The SP850 charge controller recalibrates its fuel gauge against the new cell's discharge curve during this first full cycle.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the SP850 shuts off while still showing charge remaining\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThis happens when the fuel gauge IC is still calibrated to the old cell's discharge curve. The new cell has a steeper voltage drop under load, so the controller sees a voltage cliff before the displayed percentage reaches zero. The BMS triggers a protection cutoff at that point to prevent cell damage. One full discharge-to-shutoff followed by a full uninterrupted charge resets the calibration.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eSP850 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. If the cell voltage dropped below roughly 2.5V, the BMS enters lockout mode and blocks normal charging to prevent charging a damaged cell. Connect the speaker to a known-good USB power source and leave it for 20–30 minutes without attempting to power it on — most BMS circuits include a trickle pre-charge path that recovers the cell up to a safe threshold before allowing full charge current. If the charge indicator eventually activates, let it complete the full charge cycle to 4.2V before use.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43404141166682,"sku":"BWCS-AVC120SL-1","price":23.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43404141199450,"sku":"BWCS-AVC120SL-2","price":27.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43404141232218,"sku":"BWCS-AVC120SL-3","price":29.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-AVC120SL-1.webp?v=1779369080","url":"https:\/\/batteryweb.com\/products\/avantree-sp850-replacement-battery-37v-1200mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}