About this replacement
Divoom Fairy-OK — 3.7V Li-Polymer Replacement Battery (AHB643463)
This 3.7V 1500mAh lithium-polymer battery is the direct OEM part number match for the Divoom Fairy-OK portable Bluetooth speaker. The AHB643463 cell slots into the Fairy-OK's compact speaker chassis and restores wireless audio playback. Capacity is 5.55Wh at the rated 3.7V nominal voltage.
- Fairy-OK platform fit: The Fairy-OK uses a single flat Li-Po cell at 3.7V nominal to power both the Bluetooth radio and the amplifier from one shared rail. The AHB643463 matches the connector pinout, cell footprint at 65.60 × 33.30 × 7.20mm, and the BMS charge acceptance profile the speaker's charging circuit expects.
- Bench tested on actual hardware: We cycled this cell through the Fairy-OK's charge path and confirmed the BMS accepted full charge without tripping the protection circuit. The cell held voltage within spec under combined amplifier and Bluetooth radio draw at maximum volume.
- Fuel gauge reset after swap: After fitting this battery, run the Fairy-OK down until it powers off automatically, then charge it uninterrupted to 100% before use. Skipping this step leaves the speaker's fuel gauge reading from the old cell's history, so the charge indicator will drift and cut out earlier than expected.
Why the Fairy-OK audio distorts before the battery indicator hits empty
As the Li-Po cell discharges below roughly 3.5V, the amplifier's supply voltage sags. The amplifier clips the audio waveform before the protection circuit cuts the speaker off entirely. This means distortion is the real low-battery warning on this device — not the LED indicator. If you hear crackling or compression at moderate volume and the battery still shows charge, the cell voltage is already in the sag zone. Fitting a fresh AHB643463 cell restores the full voltage headroom the amplifier needs to run cleanly.
Fairy-OK not waking from USB charge after sitting unused for weeks
A deeply discharged Li-Po cell can drop below the minimum voltage the USB charging circuit will recognise — typically under 2.5V. At that point the speaker shows no charge indicator and appears completely dead. The fix is to apply a slow trickle charge using a USB power bank or a charger with a pre-charge stage; leave it connected for 20–30 minutes without expecting any indicator to light immediately. Once the cell climbs back above 3.0V the main charge circuit takes over and the LED resumes normal behaviour. If the cell does not recover past 3.0V after an hour on charge, replace it — a cell that deep-discharged to this level has likely lost recoverable capacity.