{"product_id":"saiet-basic-replacement-battery-37v-900mah-li-ion","title":"Saiet BASIC Replacement Battery 3.7V 900mAh Li-ion","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eSaiet BASIC Series — 3.7V Li-ion Replacement Battery\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.7V 900mAh Li-ion cell for the Saiet BASIC, FOCUS VOL, Like Pronto, Prime, and two additional compatible models. It replaces an original cell that no longer holds a useful charge. Voltage and physical dimensions — 53.00 x 34.00 x 4.80mm — match the OEM specification.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eBASIC and FOCUS VOL platform fit:\u003c\/strong\u003e\n    These models share the same battery bay geometry and 3.7V single-cell supply rail. One cell covers all listed variants — no connector adapter or physical modification needed.\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 discharge-charge sequence and monitored BMS cutoff behaviour. The protection circuit tripped correctly at the low-voltage threshold and resumed charge acceptance without fault.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge recalibration on first cycle:\u003c\/strong\u003e\n    After fitting this cell, disable fast charging and run one complete discharge down to automatic shutoff, then charge uninterrupted to 100%. This gives the fuel gauge IC one full cycle to map the new cell's discharge curve before the OS starts reporting accurate percentages.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the Saiet BASIC reports wrong battery percentage after a cell swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe fuel gauge IC on the BASIC stores a learned discharge curve from the previous cell. When a new cell goes in, that stored curve no longer matches the actual voltage-to-capacity relationship of the fresh 900mAh cell. The OS reads state-of-charge from the IC, not directly from cell voltage, so the percentage shown is based on stale calibration data. One full discharge-charge cycle overwrites the old curve and brings the readout back into alignment.\u003c\/p\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\"\u003eA freshly installed cell has higher internal impedance than a broken-in one. When the modem transmits or the screen brightness spikes, current draw causes a brief voltage sag that drops below the BMS cutoff threshold — even though the displayed percentage still reads 20–30%. The phone interprets the voltage drop as cell depletion and shuts down. After two to three full discharge-charge cycles, internal impedance drops and the sag narrows; the shutdowns typically stop without any further action.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43405024428122,"sku":"BWCS-MY890SL-1","price":23.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43405024460890,"sku":"BWCS-MY890SL-2","price":27.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43405024493658,"sku":"BWCS-MY890SL-3","price":29.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-MY890SL-1.webp?v=1778767243","url":"https:\/\/batteryweb.com\/products\/saiet-basic-replacement-battery-37v-900mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}