Casper VIA P3 Replacement Battery 3.85V 3000mAh

Casper VIA P3 — 3.85V Li-Polymer Replacement Battery

This 3.85V, 3000mAh (11.55Wh) lithium-polymer cell replaces the original battery in the Casper VIA P3 smartphone. It fits the VIA P3 directly and restores capacity lost to repeated charge cycles. Physical dimensions are 72.80 × 61.40 × 3.90mm — confirm these against your existing cell before fitting.

• VIA P3 fitment: The VIA P3 uses a bare lithium-polymer pouch cell wired to the phone's charge IC and fuel gauge. This replacement matches the original cell's voltage, physical footprint, and connector orientation so the BMS handshake completes without errors.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on the VIA P3 platform. The charge IC accepted the cell without fault codes, and the BMS held voltage above 3.6V under sustained screen and modem load.
• First-cycle fast charge hold-off: On first use after installation, disable fast charging and run one complete discharge-charge cycle on standard 5V/1A. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging pushes current into an uncalibrated state.

Sudden shutdown at 20–30% on the VIA P3 after a cell swap

A new cell has a slightly different voltage-to-capacity curve than the degraded cell the fuel gauge IC was calibrated against. When the phone reads 25% remaining, the actual cell voltage may already be near 3.55V — low enough that modem transmit bursts or screen brightness spikes pull it below the 3.4V cutoff threshold. The phone shuts down even though the percentage counter says capacity remains. One full uninterrupted discharge to 0% followed by a complete charge cycle recalibrates the coulomb counter and eliminates most premature shutoffs.

VIA P3 reports wrong battery percentage after replacement

The fuel gauge IC stores a learned model of the old cell's internal resistance and charge curve in memory. After fitting a new cell, the stored model no longer matches what the hardware sees, so percentage readings jump or stall — commonly sitting at 100% for an unusually long period then dropping fast. Drain the phone fully until it powers off, then charge uninterrupted to 100% without removing the cable early. After one complete cycle the IC rebuilds its model against the new cell and percentage tracking stabilises. If jumping persists after two cycles, check that the connector is fully seated — a partially connected cell introduces resistance the gauge reads as capacity loss.