About this replacement
Bang & Olufsen BeoLit 15 / BeoPlay A2 Series — 7.4V Li-ion Replacement Battery (J406/ICR18650NH-2S)
This is a 7.4V, 2600mAh (19.24Wh) Li-ion replacement battery for the Bang & Olufsen BeoLit 15, BeoLit 17, BeoPlay A2, and BeoPlay A2 Active portable Bluetooth speakers. It fits the same battery slot as the factory pack and matches the original voltage rail. Swap it in when the original cell no longer holds a charge or the speaker shuts off early.
- BeoLit 15, BeoLit 17, BeoPlay A2, BeoPlay A2 Active: All four models share the same 7.4V two-cell Li-ion pack format and battery connector. The BMS handshake and fuel gauge calibration are identical across the range, so one part number covers all four.
- Bench tested on actual hardware: We ran this pack through charge and discharge cycles on a BeoPlay A2 Active. The BMS accepted the cell without error flags, fuel gauge tracking was consistent, and the protection circuit tripped correctly at the low-voltage cutoff threshold.
- Fuel gauge reset after installation: After fitting, run the speaker down to below 20% before doing a full charge. Skipping this step leaves the fuel gauge calibrated to the old cell's behaviour, so the charge indicator will read inaccurately from the start.
Why the BeoLit 15 shuts down mid-track at high volume
The BeoLit 15 amplifier draws a sharp current spike when driving audio at high volume. If the cell's internal resistance has risen — common in degraded packs — that spike causes a brief voltage sag below the BMS low-voltage cutoff, triggering a protection disconnect. The speaker reads this as a dead battery even if the indicator shows 30–40% remaining. A fresh cell with lower internal resistance handles the transient current without sagging, and the BMS stays closed through the peak draw.
Audio distorting before the battery indicator reaches empty
This happens when the cell voltage sags under the combined load of the amplifier and Bluetooth radio before the fuel gauge registers low. The amplifier clips because its supply rail drops below the minimum clean-power threshold — typically around 6.8V on a 7.4V nominal pack. The distortion is the amplifier's response to an undervoltage condition, not a speaker fault. Replacing the battery resolves it; after fitting the new pack, do a full charge cycle to let the fuel gauge re-anchor to the correct 8.4V full-charge reference point.