{"product_id":"t-mobile-spark-replacement-battery-37v-700mah-li-ion","title":"T-Mobile Spark 3.7V Li-ion Replacement Battery 700mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eT-Mobile Spark — 3.7V Li-ion Replacement Battery\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.7V, 700mAh Li-ion battery replaces the original cell in the T-Mobile Spark smartphone. It fits the compact Spark handset and restores power for calls, messaging, and standard smartphone functions. Capacity is 700mAh (2.59Wh) — matched to the original specification.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eSpark cell fitment:\u003c\/strong\u003e\n    The Spark uses a compact 37.68 x 37.24 x 5.41mm cell at 3.7V nominal. This replacement matches that footprint and voltage rail exactly, so the connector seats correctly and the charge IC sees the expected impedance from the first cycle.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell through a full charge-discharge sequence and monitored BMS handshake behaviour. The protection circuit responded correctly to charge termination and load cutoff at rated thresholds.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge recalibration on first use:\u003c\/strong\u003e\n    After fitting, disable fast charging and run one complete discharge down to automatic shutoff, then charge uninterrupted to 100%. This gives the fuel gauge IC a clean reference cycle against the new cell's actual discharge curve before high-current charging begins.\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 replacement cell\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis is a voltage cliff problem, not a capacity problem. The Spark's modem and display draw a combined current spike the degraded — or freshly fitted but uncalibrated — cell cannot sustain under load. Voltage drops below the BMS cutoff threshold faster than the fuel gauge IC predicted, so the phone cuts out while the percentage still reads high. Run two full discharge-charge cycles without interruption. After the second cycle, the coulomb counter recalibrates and shutdown events at 20–30% typically stop.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003ePhone shows 0% and will not power on after storage\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eIf the battery sat discharged for an extended period, the cell voltage may have dropped below 2.5V and triggered a BMS lockout. The phone will not respond to a short press of the power button. Connect the phone to a wall charger — not a USB hub — and leave it untouched for 20–30 minutes. The charge IC will trickle current into the cell until it recovers above the BMS re-enable threshold, at which point normal charging resumes. If the screen remains dark after 40 minutes on wall power, check the charging port for debris before assuming the cell is unrecoverable.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43405090062426,"sku":"BWCS-OT606SL-1","price":27.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43405090095194,"sku":"BWCS-OT606SL-2","price":31.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43405090127962,"sku":"BWCS-OT606SL-3","price":33.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-OT606SL-1.webp?v=1779369970","url":"https:\/\/batteryweb.com\/products\/t-mobile-spark-replacement-battery-37v-700mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}