About this replacement
LG LG800 / T22N — 3.7V Li-ion Replacement Battery
This 3.7V, 1100mAh Li-ion cell replaces the original battery in the LG LG800 (CDMA) and T22N handsets. It restores power to both devices, covering calls, messaging, and basic phone functions. Capacity matches the factory spec at 1100mAh (4.07Wh).
- LG800 and T22N platform fit: Both models share the same voltage rail, cell footprint, and connector pinout. A single cell covers both without modification or adapter.
- Bench tested on actual hardware: We cycled this cell through a full discharge and charge on the LG800 platform. The BMS accepted the charge handshake on the first cycle and held voltage steady through the full charge curve with no cutoff events.
- Fuel gauge recalibration on first use: After installing this cell, run one complete discharge down to automatic shutoff, then charge uninterrupted to 100%. This gives the fuel gauge IC a full reference curve to work from — skip it and the percentage readout will drift for days.
Why the LG800 reports wrong battery percentage after a cell swap
The LG800 uses a fuel gauge IC that builds its charge estimates against a stored discharge curve from the previous cell. A new cell has a different internal impedance profile, so the IC's coulomb counter starts out of sync. The phone may show 80% when the cell is closer to 50%, or drop suddenly as the estimate catches up. One full discharge-to-shutoff and uninterrupted recharge resets the reference curve and brings the readout back in line.
Sudden shutdown at 20–30% on the replacement cell
This happens when the fuel gauge IC is still calibrated to the old cell's voltage-to-capacity curve. The new cell hits a voltage cliff under load — typically when the modem fires during a call or the screen peaks in brightness — and drops below the shutdown threshold before the percentage display catches up. The phone cuts out even though the reported charge looks fine. Run one full discharge cycle to let the IC recalibrate against the new cell's actual curve. After that cycle, the shutoff threshold aligns to the real remaining capacity, and the drop-outs stop.