Sprint EVO 4G LTE Replacement Battery 3.8V 2000mAh

Sprint EVO 4G LTE (APX325CWH) — 3.8V Li-Polymer Replacement Battery

This 3.8V, 2000mAh lithium-polymer cell replaces the original battery in the Sprint HTC EVO 4G LTE (model APX325CWH). It fits directly into the battery compartment and connects to the same charge management circuit. Capacity is rated at 7.6Wh.

• EVO 4G LTE platform fit: The EVO 4G LTE uses a fixed 3.8V Li-Polymer cell with a 3-pin connector feeding the phone's charge IC and fuel gauge IC. This replacement matches that connector pinout and nominal voltage so the BMS handshake completes without error flags.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the EVO 4G LTE platform. The BMS accepted the cell on the first connection, charge current stepped correctly through CC/CV phases, and the fuel gauge IC began tracking state-of-charge without fault codes.
• Fuel gauge recalibration on first use: After installation, disable fast charging and run one full discharge-to-charge cycle before using the phone normally. This lets the fuel gauge IC build a fresh discharge curve against the new cell — skipping this step causes the percentage counter to read inaccurately for the first several cycles.

Why the EVO 4G LTE reports wrong battery percentage after a cell swap

The fuel gauge IC stores a learned discharge curve from the old cell. When a new cell goes in, that stored curve no longer matches actual cell chemistry and capacity. The IC interpolates percentage from voltage readings that now map incorrectly, so the display shows stale or compressed numbers. One full discharge below 10% followed by an uninterrupted charge to 100% forces the IC to rewrite its reference curve against the new cell.

Sudden shutdown at 20–30% on the replacement cell

This happens when the fuel gauge IC hasn't completed recalibration and the phone hits a voltage cliff under load. The modem and display draw current spikes that drop cell voltage faster than the uncalibrated IC predicts. The system reads available voltage as below the shutdown threshold and cuts power even though the fuel gauge still shows charge remaining. Run the phone down to automatic shutdown once, charge fully to 100%, and the IC resets its low-voltage cutoff reference to match the new cell's actual discharge curve.