Beghelli SLV20 Replacement Battery 3.7V 1200mAh Li-ion

Beghelli SLV20 / SLV20+ / SLV30 — 3.7V Li-ion Replacement Battery

This 3.7V 1200mAh Li-ion cell replaces the original battery in the Beghelli SLV20, SLV20+, and SLV30 smartphones. At 53.00 × 33.90 × 5.70mm, it matches the physical footprint of the factory cell. Capacity is 4.44Wh — identical to the original spec.

• SLV20, SLV20+, and SLV30 compatibility: All three models share the same battery bay dimensions, connector pinout, and BMS communication protocol — one cell covers the full range without modification.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the SLV20 platform. The BMS handshake completed correctly, charge termination triggered at the expected voltage, and the protection circuit tripped cleanly on overcurrent.
• Fuel gauge recalibration on first cycle: On first use after installation, disable fast charging and run one complete discharge-charge cycle from full to flat. This lets the fuel gauge IC map the new cell's discharge curve before it begins reporting percentages to the OS — skip this step and the gauge will read off the old curve for days.

Sudden shutdown at 20–30% on the SLV20 after a cell swap

This happens because the fuel gauge IC is still calibrated to the old cell's internal resistance profile. When the modem fires a high-current burst or the screen peaks, the new cell sags in voltage faster than the gauge expects — the phone reads 25% on screen but the actual cell voltage has already dropped below the hardware cutoff threshold. The fix is a full discharge-charge cycle with no fast charging on the first pass. After one complete cycle the coulomb counter resets against the new cell and the shutdowns stop.

Phone feels warm near the battery during the first few charges

A new Li-ion cell has higher internal impedance than a used one — the charge IC doesn't know this yet and pushes current at the rate it learned from the old cell. That mismatch generates heat in the first two or three charge cycles. Keep the phone out of a case during those first cycles so heat can dissipate from the back panel. Impedance drops as the cell is conditioned and the warmth settles by the third full charge.