LG G4050 Replacement Battery BSL-70G 3.7V 850mAh

LG G4050 — 3.7V Li-ion Replacement Battery (BSL-70G)

This is a 3.7V 850mAh Li-ion replacement battery for the LG G4050 mobile phone. It uses OEM part number BSL-70G and fits both the G4050 and G-4050 model variants. Swap it in when the original cell no longer holds a charge or fails to power the handset through a normal day.

• G4050 and G-4050 compatibility: Both model designations share the same chassis, battery bay dimensions, and connector pinout. The BSL-70G seats and connects identically in either variant — no adapter or modification needed.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on the G4050 platform. The BMS accepted the charge handshake immediately, and protection circuits tripped correctly at the low-voltage cutoff threshold — no overcharge, no false shutdown above 3.0V.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one complete discharge-to-charge cycle. This lets the fuel gauge IC map its coulomb counter against the new cell's actual discharge curve before normal operation resumes.

Sudden shutdown at 20–30% on the G4050 after a cell swap

This is a voltage cliff issue. The new cell has a slightly different discharge curve than the degraded original, so the fuel gauge IC — still calibrated to the old cell — misreads remaining capacity. Under a load spike from the modem or display, the cell voltage drops below the BMS cutoff threshold while the OS still shows 20–30% remaining. The fix is one full discharge cycle with no fast charging, which forces the coulomb counter to recalibrate. After that cycle, the percentage readings stabilise and shutdown behaviour returns to normal.

G4050 reporting incorrect battery percentage after replacement

The fuel gauge IC stores a learned discharge profile for the cell it was calibrated against. A new cell has different internal resistance and a shifted voltage-to-capacity curve, so early readings will be off — sometimes jumping several percent or dropping faster than expected. This is not a fault with the replacement cell. Run the phone from 100% down to automatic shutoff, then charge uninterrupted to 100% with fast charging disabled. That single cycle re-anchors the fuel gauge IC to the new cell and percentage accuracy returns.