{"product_id":"tunstall-lifeline-vi-replacement-battery-37v-1500mah-li-ion","title":"Tunstall Lifeline Vi Replacement Battery 3.7V 1500mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eTunstall Lifeline Vi \/ Vi+ — 3.7V Li-ion Replacement Battery (D3706008a)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.7V 1500mAh Li-ion cell replaces the OEM battery in the Tunstall Lifeline Vi and Lifeline Vi+ personal emergency response devices. It matches the original D3706008a specification in voltage, capacity, and physical dimensions. Capacity is 5.55Wh — no upsizing, no chemistry substitution.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eLifeline Vi and Vi+ compatibility:\u003c\/strong\u003e\n    Both models run the same 3.7V battery rail with the same BMS handshake protocol. The D3706008a part number covers both variants — the Vi+ shares the same connector, cell footprint, and BMS communication as the standard Vi.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell through the Lifeline Vi's charge IC and monitored BMS response at each stage. The protection circuit responded correctly to both charge cutoff and low-voltage thresholds. No false fault codes were triggered after a complete charge cycle.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-installation self-test requirement:\u003c\/strong\u003e\n    After fitting this cell, allow the device to complete its full power-on self-test without interruption. The Lifeline Vi runs a BMS verification sequence at startup — cutting power during this window generates a persistent battery fault flag that will not clear until the next complete reboot.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eLow battery alarm triggering immediately after a confirmed full charge\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe Lifeline Vi's BMS uses a learned threshold calibrated to the OEM cell's charge profile. A new replacement cell can read as below threshold on the first cycle because the BMS hasn't yet mapped its voltage curve. This is not a faulty cell — it is a calibration gap. Run one complete charge-discharge-charge cycle and the BMS will update its reference. The alarm should clear once the cell voltage holds above 3.6V under the device's standby load after that conditioning cycle.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eDevice will not power on after the replacement cell was stored before fitting\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eLi-ion cells self-discharge during storage. If the cell voltage has dropped below approximately 2.5V, the Lifeline Vi's BMS enters a protection lockout and blocks power-on entirely. Connect the device to its mains charger for at least 30 minutes before attempting to power it on — the charge IC applies a low-rate pre-charge trickle below 3.0V to recover the cell safely. Once the cell climbs past 3.0V, normal charging resumes and the device will boot.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43381416067162,"sku":"BWCS-RMP100MD-1","price":38.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43381416099930,"sku":"BWCS-RMP100MD-2","price":45.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43381416132698,"sku":"BWCS-RMP100MD-3","price":49.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-RMP100MD-1.webp?v=1778900625","url":"https:\/\/batteryweb.com\/products\/tunstall-lifeline-vi-replacement-battery-37v-1500mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}