{"product_id":"garmin-std-810g-replacement-battery-387v-340mah-li-polymer","title":"Garmin Fenix 2 STD-810G Replacement Battery 3.87V 340mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eGarmin Fenix 2 \/ Instinct Solar — 3.87V Li-Polymer Replacement Battery (361-00164-10)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.87V, 340mAh lithium-polymer cell replaces the original battery in the Garmin Fenix 2 smartwatch (STD-810G) and Instinct Solar. It matches the OEM footprint at 36.80 × 24.70 × 3.00mm, so it seats correctly against the watch's connector without modification. Voltage and capacity are drawn from the product data, not estimated.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eFenix 2 and Instinct Solar compatibility:\u003c\/strong\u003e\n    Both watches share OEM part numbers 361-00164-10, 361-00164-00, and 361-00136-10. The connector pinout and cell dimensions are identical across this group, so one cell covers both platforms without adapter work.\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 Fenix 2 unit. The BMS accepted the new cell without fault codes, and the fuel gauge responded correctly once a full charge cycle completed from near-zero.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFirst charge after cell swap:\u003c\/strong\u003e\n    Place the watch on its magnetic charger immediately after fitting this cell and charge it fully to 100% before use. The fuel gauge IC on these Garmin platforms loses its reference when the cell is removed — it cannot recalibrate without a complete charge cycle from near-zero.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eGPS and continuous heart rate monitoring load on a fresh 340mAh cell\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe Fenix 2 runs GPS, barometric altimeter, and optical heart rate simultaneously during activity tracking. That combined draw is substantial relative to a 340mAh cell. A new cell at full impedance will show a steeper apparent voltage drop during the first few charge-discharge cycles than the worn cell it replaced — this is normal cell settling, not a capacity defect. After three to five full cycles, the voltage curve stabilises and the fuel gauge reads accurately.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWatch not pairing with phone after battery replacement\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eRemoving the cell cuts power to the BLE stack entirely, which drops the active pairing session stored in volatile memory. The phone's Bluetooth settings still show the watch as a saved device, but the handshake no longer completes. Go into your phone's Bluetooth settings, forget the Garmin device, then re-pair through the Garmin Connect app from scratch. The watch needs to be powered on and showing the pairing screen before the app scan will find it.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416152670298,"sku":"BWCS-GMT810SL-1","price":33.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416152703066,"sku":"BWCS-GMT810SL-2","price":39.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416152735834,"sku":"BWCS-GMT810SL-3","price":43.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-GMT810SL-1.webp?v=1779760467","url":"https:\/\/batteryweb.com\/products\/garmin-std-810g-replacement-battery-387v-340mah-li-polymer","provider":"BatteryWeb","version":"1.0","type":"link"}