{"product_id":"zte-f290-replacement-battery-37v-800mah-li-ion","title":"ZTE F290 Replacement Battery 3.7V 800mAh Li3709T42P3h463657","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eZTE F290 \/ N281 \/ Z221 \/ Z222 — 3.7V Li-ion Replacement Battery (Li3709T42P3h463657)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.7V 800mAh (2.96Wh) Li-ion cell for the ZTE F290, N281, Z221, and Z222 candybar-style phones. It replaces OEM parts Li3709T42P3h463657 and Li3708T42P3h463657. The cell fits the original battery bay without modification and connects through the same three-pin contact strip.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eF290 \/ N281 \/ Z221 \/ Z222 platform fit:\u003c\/strong\u003e\n    These four models share the same battery bay dimensions (46.26 × 35.60 × 5.68mm), voltage rail, and three-pin connector layout. The BMS handshake uses the same thermistor pin arrangement across the group, so one cell covers all four.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell on the F290 platform and confirmed the BMS accepted the cell on first insertion, charge current ramped correctly through CC\/CV phases, and the protection circuit tripped at expected low-voltage cutoff without locking the board.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge recalibration on first cycle:\u003c\/strong\u003e\n    After installation, run one full discharge to automatic power-off, then charge uninterrupted to 100% before normal use. The phone's fuel gauge IC was calibrated to the old cell's discharge curve — one complete cycle resets the coulomb counter against the new cell so percentage readings stay accurate.\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\"\u003eThe ZTE F290's fuel gauge IC maps a voltage-to-percentage curve learned from the previous cell. A new cell has a flatter discharge curve and holds voltage higher for longer before a sharp drop. When the phone expects 20% remaining but the new cell is already near its voltage cliff, the modem or display load pulls current the cell can't sustain at that state of charge — the phone shuts off instantly. One full discharge-charge cycle lets the coulomb counter relearn the curve. After that cycle, shutdowns below 20% stop.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003ePhone not powering on after the battery sat in storage\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eLi-ion cells self-discharge at roughly 2–3% per month. If the replacement cell sat in a warehouse for an extended period before you received it, the cell voltage may have dropped below 3.0V — the threshold where the BMS enters lockout to prevent damage. The phone will show nothing when you press power or plug in a charger. Connect the phone to a charger and leave it for 20–30 minutes without pressing any buttons; the protection circuit allows a trickle current below 3.0V to recover the cell. Once voltage climbs above 3.0V, normal charging resumes.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43405062471770,"sku":"BWCS-ZTF290SL-1","price":23.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43405062504538,"sku":"BWCS-ZTF290SL-2","price":26.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43405062537306,"sku":"BWCS-ZTF290SL-3","price":28.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-ZTF290SL-1.webp?v=1779369899","url":"https:\/\/batteryweb.com\/products\/zte-f290-replacement-battery-37v-800mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}