About this replacement
LG G4 Beat / G4s — 3.85V Li-ion Replacement Battery (BL-49SF)
The BL-49SF is a 3.85V, 2200mAh Li-ion cell that fits the LG G4 Beat, G4s, H735, and H735L among other H-series variants. It replaces the original removable cell when capacity has dropped or the battery no longer holds a charge. Dimensions are 68.10 × 48.38 × 4.86mm — the same footprint as the stock cell.
- H735-series compatibility: The G4 Beat, G4s, H735, and H735L share the same battery bay geometry, connector pinout, and BMS handshake requirements. All pull from the same 3.85V nominal rail, so one cell covers the full variant group without modification.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on an H735 unit. The BMS accepted the cell immediately, charge termination triggered correctly at full capacity, and protection cutoffs activated as expected under load.
- Fuel gauge recalibration on first use: 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 pushes current into an uncalibrated cell — otherwise percentage readings will drift early.
Sudden shutdown at 20–30% on the replacement cell
This is a voltage-cliff issue, not a faulty cell. The fuel gauge IC is still referencing the discharge curve of the worn original battery. When the new cell hits a steep voltage drop under modem or screen load, the IC interprets it as a critical low-voltage event and triggers a shutdown — even though the reported percentage looks safe. One full discharge-charge cycle without fast charging resets the coulomb counter and realigns the IC to the new cell's actual curve. After calibration, shutdowns at 20–30% typically stop.
Phone will not power on after sitting in storage with the replacement installed
Li-ion cells self-discharge during storage. If the cell dropped below approximately 2.5V per cell, the BMS enters a lockout state and blocks normal charging to prevent damage. Plugging into a standard charger may show no response at all. Connect to a low-current USB source — a PC USB port works — and leave it for 15–20 minutes before attempting a full charge. This trickle input is often enough to bring the cell voltage above the BMS re-enable threshold, after which normal charging resumes.