About this replacement
LG Optimus G Pro E940 / E980 Series — 3.7V Li-ion Replacement Battery (BL-48TH)
This is a 3.7V, 2000mAh Li-ion cell replacing the BL-48TH in the LG Optimus G Pro lineup. It fits the E940, E980, E977, and six additional model variants. If your phone no longer holds a charge or shuts down unexpectedly, this is the direct cell replacement.
- E940 / E980 / E977 compatibility: These models share the same battery bay dimensions (83.20 × 56.50 × 5.00mm), connector pinout, and BMS handshake protocol — which is why a single BL-48TH cell covers the entire G Pro range.
- Bench tested on actual hardware: We cycled this cell through charge, load, and cutoff on G Pro hardware. The BMS accepted the cell without fault flags, and the protection circuit tripped correctly at low-voltage threshold — no runaway, no false full-charge cutoff.
- Fuel gauge recalibration after install: On first use after installation, disable fast charging and run one complete discharge-to-charge cycle. This lets the G Pro's fuel gauge IC map the new cell's discharge curve before high-current charging pushes current into an uncalibrated cell.
Sudden shutdown at 20–30% on the BL-48TH replacement
This happens when the fuel gauge IC is still calibrated to the old cell's voltage curve. The G Pro reads voltage, not direct capacity — so it estimates remaining charge based on the previous cell's discharge profile. A new cell hits a steeper voltage cliff under modem and screen load than the worn cell the IC learned from. The phone interprets that drop as a hard cutoff event. One full discharge-charge cycle without fast charging resets the coulomb counter and eliminates most of these phantom shutdowns.
Phone not powering on after the replacement cell sat in storage
Li-ion cells self-discharge in storage. If the BL-48TH dropped below approximately 2.5V per cell, the BMS enters lockout to prevent damage — and the phone shows no response at all, not even a low-battery screen. Plug into a wall charger (not a PC USB port, which may not supply enough current to wake the BMS) and leave it for 15–20 minutes before attempting to power on. If voltage recovers above the BMS threshold, the charger IC takes over and normal charging resumes. If there is still no response after 30 minutes on a wall adapter, the cell has dropped below recoverable voltage.