LG KU800 Replacement Battery LGLP-GBAM 3.7V 850mAh Li-ion

LG KU800 — 3.7V Li-ion Replacement Battery (LGLP-GBAM)

This is a 3.7V Li-ion cell rated at 850mAh (3.15Wh), built to the same spec as the original LGLP-GBAM. It fits the LG KU800 directly, with no modification to the battery compartment or contacts. When the original cell degrades and can no longer sustain voltage under screen or call load, this is the direct swap.

• KU800 compatibility: The KU800 uses a single-cell Li-ion pack at 3.7V nominal with a specific contact pitch and BMS communication line. This replacement matches that electrical footprint — voltage, connector orientation, and protection circuit output all align with what the phone's charge IC expects.
• Bench tested on actual hardware: We cycled this cell through charge and discharge while monitoring BMS cutoff thresholds. The protection circuit triggered correctly at both low-voltage and over-current limits, and the charge IC accepted the cell without error flags.
• Fuel gauge recalibration on first use: After fitting this cell, run one complete discharge down to auto-shutdown, then charge uninterrupted to 100%. The KU800's fuel gauge IC calibrates against the cell's discharge curve on that first full cycle — skipping it causes the percentage readout to drift off from the actual state of charge.

Sudden shutdown at 20–30% on the KU800 after a cell swap

The KU800's fuel gauge IC was calibrated to the discharge curve of the original, worn cell. A fresh 850mAh cell has a steeper voltage cliff at the low end compared to a degraded one. When the phone reports 20–30% remaining, the new cell's actual resting voltage may already be approaching the BMS cutoff threshold. Under modem or backlight load, voltage sags past that threshold and the BMS trips instantly. One full discharge-to-shutdown cycle followed by an uninterrupted full charge resets the coulomb counter against the new cell's curve.

KU800 not powering on after the replacement battery sat in storage

Li-ion cells self-discharge during storage. If this battery shipped or was stored for an extended period, the cell voltage may have dropped below 2.5V — the threshold at which most BMS circuits lock out to prevent deep-discharge damage. The phone will appear completely dead and will not respond to the power button. Connect the phone to a charger and leave it for at least 15–20 minutes before attempting to power on; the charge IC needs to bring the cell above the BMS re-enable threshold, typically around 3.0V, before the circuit closes and the phone can boot.