About this replacement
Sony SRS-XE200 — 3.7V Li-Polymer Replacement Battery (SP903867)
This is a 3.7V, 2500mAh Li-Polymer battery for the Sony SRS-XE200 portable Bluetooth speaker. It replaces part numbers SP903867, MDA054PA, and N4HUHQB00001. If the original cell has degraded and the speaker no longer holds a charge through a listening session, this is the direct swap.
- SRS-XE200 fit: The SRS-XE200 uses a single flat Li-Polymer cell at 3.7V nominal. The cell dimensions are 63.00 × 36.00 × 8.80mm. Any deviation in thickness or connector orientation will prevent proper seating against the speaker's internal frame.
- Bench tested on actual hardware: We ran the cell through charge and discharge cycles on the bench. The BMS accepted charge input cleanly, held stable voltage through simulated amplifier draw, and cut off correctly at the low-voltage threshold without dropping into protection mode prematurely.
- Fuel gauge reset after install: After fitting a new cell, run the SRS-XE200 down to auto-shutoff from a full charge before recharging. Skipping this step leaves the onboard fuel gauge calibrated to the old cell's degraded capacity, so the battery indicator will read inaccurately from day one.
Capacity fade from constant top-off charging on the SRS-XE200
The SRS-XE200 is commonly left on a USB-C charger at a desk between uses. Li-Polymer cells held near 100% charge for extended periods develop elevated internal resistance faster than cells allowed to cycle. This doesn't show up immediately — it appears as a gradual shortening of playtime over several months. Allowing the cell to drop below 20% at least once a month before recharging slows this degradation and keeps the fuel gauge tracking accurately.
Audio distorting before the battery indicator reaches empty
This happens when a degraded cell can no longer sustain voltage under the combined draw of the amplifier and Bluetooth radio. At higher playback volumes, current demand spikes and cell voltage sags below the amplifier's clean operating threshold — producing clipping distortion even though the indicator shows remaining charge. The battery indicator reads state of charge, not instantaneous voltage under load. Fitting a fresh 2500mAh cell restores the voltage headroom needed to maintain clean output down to the actual cutoff point near 3.0V.