Teufel AIRY Compatible Battery 3.7V 250mAh Li-Polymer 502030

Teufel AIRY — 3.7V Li-Polymer Replacement Battery (502030)

This 3.7V, 250mAh Li-Polymer cell replaces the original 502030 battery in the Teufel AIRY wireless earbuds. It restores audio playback and call functionality when the original cell has degraded after repeated charge cycles. Dimensions are 31.50 × 20.00 × 5.00mm — confirm against your existing cell before fitting.

• Teufel AIRY fitment: The AIRY earbuds run a compact Li-Polymer cell on a single 3.7V rail. The 502030 format is specific to this housing — the cell dimensions and connector orientation must match exactly for the BMS to complete its handshake with the charging circuit.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the AIRY platform. The BMS accepted the pack without error flags, and the protection circuit tripped correctly at the low-voltage cutoff threshold.
• First charge after fitting: Seat the headset in its base station and allow a complete charge cycle before taking a call. The AIRY base needs to log the new cell to calibrate its talk-time indicator — pulling it off charge early after fitting will leave the estimate inaccurate for several sessions.

Why the AIRY cuts out mid-call on a new battery

The AIRY combines audio decode and DECT radio draw in a very small housing. Under that sustained combined load, a cell that hasn't completed its first full cycle can sag below the BMS cutoff threshold before the rated capacity is consumed. This isn't a fault — it's the cell operating conservatively until it's been through two or three full charge cycles. After conditioning, the voltage curve flattens and the cutouts stop.

Base station shows full charge but headset goes silent after short use

A replacement cell arrives at storage voltage — typically 3.6–3.7V — not at full charge. The base station can misread this as a charged pack and display a full indicator before the cell has actually been topped up. The fix is straightforward: place the headset in the base, leave it for a complete uninterrupted charge cycle, and verify the charge LED completes its sequence. After that first full cycle, the base indicator will reflect actual cell state accurately.