Cowon PMP A2 20GB Compatible Battery 3.7V 3600mAh

Cowon PMP A2 / A3 Series — 3.7V Li-Polymer Replacement Battery

This 3.7V, 3600mAh Li-Polymer battery replaces the original cell in the Cowon PMP A2 20GB, PMP A2 30GB, PMP A3 60GB, and PMP A3 80GB portable media players. These mid-2000s digital audio and video players are known for their audio quality, and a failing original cell is the most common reason they stop functioning. Voltage and form factor match OEM spec at 107.90 × 59.91 × 5.00mm.

• A2 and A3 platform compatibility: The A2 and A3 share the same battery bay dimensions, connector pin-out, and 3.7V supply rail. The BMS on both models uses the same voltage thresholds for charge acceptance and low-battery cutoff, so one cell covers the full range of these players.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on an A3 unit. The onboard BMS accepted charge current normally, held the full voltage curve through playback, and tripped the low-voltage cutoff at the expected threshold without premature shutdown.
• Post-swap initialisation on the A2 and A3: After fitting a new cell, charge fully before first use. These players frequently enter deep discharge protection after sitting unused, and the firmware requires a slow trickle charge before it will accept normal charge current — skipping this step leaves the player unresponsive at the charge screen.

Battery percentage jumping erratically after a cell swap on the A2 and A3

The Cowon A2 and A3 use a voltage-threshold gauge — there is no fuel-gauge IC recalibrating coulombs. After fitting a new cell, the firmware maps displayed percentage against a voltage curve it learned from the old, degraded cell. The new cell holds a flatter discharge curve, which the firmware reads as sudden jumps between percentage bands. Run two full charge and discharge cycles and the displayed percentage will stabilise as the firmware recalibrates its voltage reference points.

Playback cutting out before the battery indicator shows empty

The audio amplifier stage in these players draws a higher instantaneous current than the backlight or UI. As a degraded cell approaches end of discharge, its internal resistance causes a voltage sag large enough to drop below the amplifier's minimum supply voltage — even while the indicator still shows charge remaining. The player then shuts down or mutes audio abruptly. A fresh 3600mAh cell at full charge holds a stable voltage under this load, eliminating premature cutoff. If the issue persists with a new cell, confirm the pack has completed at least one full charge cycle to 4.2V before testing.