Casper VIA V6 Replacement Battery 3.8V 3000mAh Li-Polymer

Casper VIA V6 / VIA V6X — 3.8V Li-Polymer Replacement Battery

This 3.8V 3000mAh Li-Polymer cell replaces the original battery in the Casper VIA V6 and VIA V6X smartphones. It fits both models directly, restoring capacity lost to cell age, heat damage, or heavy daily use. Rated at 11.4Wh with physical dimensions of 86.50 × 65.80 × 4.10mm.

• VIA V6 and V6X compatibility: Both models share the same battery bay dimensions, connector pinout, and charge IC voltage rail at 3.8V nominal. One cell covers both variants without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the VIA V6 platform. The BMS accepted the charge IC handshake cleanly, held voltage above 3.5V under display and modem load, and tripped protection correctly at the low-voltage cutoff threshold.
• First-cycle fast charge caution: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC recalibrate its coulomb counter against the new cell's discharge curve before high current is pushed into an uncalibrated cell.

Why the VIA V6 reports wrong battery percentage after a cell swap

The fuel gauge IC on the VIA V6 stores a learned discharge curve from the old cell. When a new cell goes in, that stored curve no longer matches the actual voltage-to-capacity relationship. The phone reads voltage correctly but maps it to the wrong percentage. One full discharge down to auto-shutdown followed by a complete charge to 100% resets the coulomb counter and forces the IC to relearn the new cell's curve.

Sudden shutdown at 20–30% on the replacement cell

This happens when the phone's display or modem draws a current spike and the cell voltage drops sharply under load — a voltage cliff the fuel gauge did not anticipate. The phone reads 25% but the cell cannot sustain voltage above the system's minimum threshold, triggering an immediate shutdown. It is not a faulty cell; it is an uncalibrated gauge. Run two full discharge-charge cycles and the shutdowns stop once the fuel gauge IC has accurate data. If shutdowns continue past three full cycles, check that resting cell voltage reads above 3.7V with a multimeter before charging.