Sony SRS-XB01 Replacement Battery 3.6V 700mAh Ni-MH

Sony SRS-XB01 — 3.6V Ni-MH Replacement Battery (HFR-AAA800*3)

This is a 3.6V, 700mAh Ni-MH battery pack for the Sony SRS-XB01 portable Bluetooth speaker. It replaces the internal rechargeable pack that powers the speaker's wireless audio system. When the original cell degrades and the speaker no longer holds a charge, this pack restores full portable functionality.

• SRS-XB01 fit: The XB01 uses a compact three-cell Ni-MH pack in a fixed internal configuration. This battery matches the 3.6V nominal rail, physical footprint, and connector orientation the speaker's charge management circuit expects. No modifications required for installation.
• Bench tested on actual hardware: We cycled this pack through charge and discharge on the SRS-XB01 platform. The onboard charge controller accepted the battery without fault codes, and the BMS held voltage within spec across low and high audio output levels.
• Ni-MH cycle management on the XB01: Unlike Li-ion cells, Ni-MH chemistry is susceptible to voltage depression from constant shallow top-off charges. Run the XB01 down below 20% at least once a month before recharging — this prevents fuel gauge drift and keeps the cell's effective capacity from compressing over time.

Audio distorting before the battery indicator reaches empty on the XB01

The XB01's amplifier needs a stable voltage floor to reproduce audio cleanly. As a Ni-MH cell ages, its internal resistance climbs — voltage sags under the amplifier's current draw before the cell is technically empty. The speaker's charge indicator reads a remaining percentage based on cell voltage at rest, not under load, so the gauge can show partial charge while the amp is already clipping. If audio distortion appears well before the low-battery indicator, the original pack has degraded and the internal resistance is too high to sustain amplifier demand — replacing the cell resolves this at the source.

Bluetooth dropping out at high volume after fitting a new battery

At maximum volume, the XB01 draws simultaneously from both the amplifier and the Bluetooth radio module — combined current demand spikes sharply during loud transients. If the battery connection is not fully seated, contact resistance adds to the pack's internal resistance, and the combined draw causes a brief voltage dip that resets the radio. Check that the battery connector is fully pressed in and that no foam or debris is compressing the pack at an angle. A solid connection will keep voltage stable above the 3.0V threshold the radio requires to stay linked.