Bang & Olufsen Beoplay EQ Charging Case Compatible Battery 3.7V 450mAh

Bang & Olufsen Beoplay EQ Charging Case — 3.7V Li-Polymer Replacement Battery (102026)

This 3.7V, 450mAh Li-Polymer cell replaces the internal battery in the Bang & Olufsen Beoplay EQ Charging Case. It fits the case unit directly — not the earbuds themselves. Replace it when the case stops holding a charge and can no longer top up the earbuds between uses.

• Beoplay EQ Charging Case fit: The case uses a compact Li-Polymer cell at 3.7V nominal to power its internal charge circuit. This replacement matches the OEM voltage rail and physical footprint at 25.90 × 19.20 × 9.00mm — the BMS in the case reads cell voltage directly, so matching chemistry and voltage matters here.
• Bench tested on actual hardware: We cycled this cell through the case's charge-in and charge-out sequence and confirmed the BMS accepted the new pack without error, completing full charge cycles to both the case and the earbuds.
• First-cycle protocol for the Beoplay EQ case: After fitting the new cell, place the case on its USB-C charge cable and let it reach full charge before putting earbuds inside. The case firmware logs the new cell's baseline voltage on that first cycle — skip it and the charge indicator can misread the state of charge for weeks.

Why the Beoplay EQ case shows full but cuts the earbuds off early

The case uses a fuel gauge that references a stored charge curve, not a live cell reading. When the original cell degrades, that curve drifts — the indicator shows full charge while the actual cell voltage has already dropped below the threshold needed to push current into the earbuds. Fitting a new cell resets nothing automatically. The case needs one complete charge-from-flat cycle over USB-C to re-anchor the fuel gauge to the new cell's real capacity. After that cycle, the indicator and actual charge state align again.

Case warm to the touch while charging the earbuds

The Beoplay EQ case charges both earbuds simultaneously while the case cell itself may also be taking charge from USB-C. That parallel draw in a small sealed housing generates noticeable warmth — it is normal up to mild warmth but should not feel hot. If the case gets genuinely hot, disconnect USB-C and let the case finish charging the earbuds on its own stored charge. Check that the USB-C port and cable are clean and delivering a stable 5V — a fluctuating input voltage forces the charge circuit to retry repeatedly, which increases heat output.