{"product_id":"banno-gt03b-replacement-battery-37v-1200mah-li-ion","title":"BANNO GT03B Replacement Battery 3.7V 1200mAh Li-ion","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eBANNO GT03B — 3.7V Li-ion Replacement Battery\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.7V, 1200mAh (4.44Wh) Li-ion cell for smartphones running the GT03B battery form factor. It physically measures 53.00 × 33.90 × 5.70mm — check that against your current cell before ordering. Capacity is sourced from the product data, not inflated.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eGT03B form factor:\u003c\/strong\u003e\n    The GT03B slot uses a fixed connector pinout and a specific cell footprint. This replacement matches that footprint exactly. Forcing a mismatched cell into the bay can bend contact pins and permanently damage the charge IC on the board.\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-to-cutoff sequence and monitored BMS response. The protection circuit tripped cleanly at the low-voltage threshold and accepted charge current without event on the subsequent cycle.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge recalibration on first use:\u003c\/strong\u003e\n    On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging is applied to an uncalibrated cell. Skip this step and the OS percentage readout will drift for weeks.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the phone reports wrong battery percentage after a cell swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe fuel gauge IC — a small coulomb-counting chip on the motherboard — builds a model of the cell's capacity over its lifetime. When you swap in a new cell, that model is still calibrated to the old, degraded cell. The chip underestimates remaining capacity because it expects voltage to drop faster than it does with a fresh cell. One full discharge to shutdown followed by a full uninterrupted charge resets the learned curve. After that cycle, percentage accuracy stabilises.\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\"\u003eThis happens when the modem or display draws a current spike the cell cannot sustain at that state of charge — the voltage drops below the BMS cutoff threshold instantly, and the phone shuts off before the OS can react. It is not a faulty cell. It is the fuel gauge IC reading a flat discharge curve from the old cell model and misreporting usable capacity. Run one full cycle to 0% shutdown, then charge uninterrupted to 100%. The cliff should move below 10% once the IC recalibrates to the actual 3.7V cell curve.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43405031047258,"sku":"BWCS-NK5CHL-1","price":40.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43405031080026,"sku":"BWCS-NK5CHL-2","price":47.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43405031112794,"sku":"BWCS-NK5CHL-3","price":52.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-NK5CHL-1.webp?v=1779369842","url":"https:\/\/batteryweb.com\/products\/banno-gt03b-replacement-battery-37v-1200mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}