About this replacement
K-Touch L820 / L820c — 3.8V Li-ion Replacement Battery (TBL5995A)
This is a 3.8V, 2000mAh (7.6Wh) Li-ion cell for the K-Touch L820 and L820c smartphones. It replaces OEM part numbers TBL5995A and TBE5707B. The battery fits the original battery bay directly and connects via the stock flex connector.
- L820 and L820c compatibility: Both models share the same battery bay dimensions (58.50 × 50.90 × 5.30mm), voltage rail, and BMS handshake protocol — one cell covers both variants without modification.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the L820 platform. The BMS accepted the charge protocol on the first cycle, and the protection circuit tripped correctly at the low-voltage cutoff threshold without requiring a manual reset.
- Fuel gauge recalibration on first use: On first installation, disable fast charging and run one complete discharge-charge cycle before enabling it again. The fuel gauge IC on the L820 calibrates its coulomb counter against the cell's actual discharge curve on that first cycle — skipping this step causes percentage readings to drift or jump erratically for days afterward.
Sudden shutdown at 20–30% on the L820 after a cell swap
This happens because the fuel gauge IC still holds the discharge curve of the old, degraded cell. The new cell's actual voltage under modem and screen load drops faster than the IC predicts at that state-of-charge window. The phone interprets this voltage sag as a critical low and triggers an emergency shutdown. One full discharge-to-cutoff and recharge cycle forces the IC to remap the curve against the new cell — shutdowns at 20–30% typically stop after that recalibration pass.
Phone feels warm near the battery during the first few charges
A new Li-ion cell has higher internal impedance than a broken-in cell. The charge IC on the L820 pushes the same current into a higher-resistance cell, which generates more heat than you'd see on a well-cycled battery. This is normal for the first three to five charge cycles as the cell's impedance settles. If the phone still runs hot after five cycles, check that the battery connector is fully seated — a partial connection raises contact resistance and compounds the heating.