Sennheiser BA1029 Wireless Microphone Replacement Battery 2.4V 300mAh

Sennheiser EKI1029 / Receiver EKI 1029 — 2.4V Ni-MH Replacement Battery (BA1029)

This is a 2.4V, 300mAh Ni-MH rechargeable battery for the Sennheiser EKI1029 wireless transmitter and receiver system. It replaces OEM part numbers BA1029 and BA 1029. The EKI1029 runs on this cell during live sound, presentation, and broadcast sessions where a stable, rechargeable power source is required.

• EKI1029 transmitter and receiver compatibility: Both the transmitter and receiver units in the EKI1029 system draw from the same 2.4V Ni-MH cell format. The shared voltage rail and connector spec mean one battery type covers both halves of the wireless link — no separate cells needed.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the EKI1029 platform. The BMS accepted charge without fault flags, and the battery held within the expected voltage window across the full discharge curve without premature cutoff.
• Contact cleaning between battery swaps: The EKI1029's battery contacts are small and close-spaced. Residue from Ni-MH cells can build up faster than on lithium systems. Wipe the contacts with a dry cotton swab before fitting a new cell — oxidation on these terminals causes voltage drop that the system reads as a low battery.

Transmitter dropping signal mid-broadcast on a freshly installed battery

The EKI1029 transmitter combines RF output and DSP processing in a single current draw. Under peak load — during active transmission with signal processing engaged — the combined draw can spike above what a partially depleted or poorly seated Ni-MH cell will deliver. The BMS reads this as an under-voltage condition and cuts power momentarily, dropping the RF link. The fix is to confirm the battery is fully charged before the session starts and that it is seated firmly so contact resistance is near zero.

Receiver not syncing after swapping the transmitter battery

When the transmitter loses power during a battery swap, some EKI1029 system configurations drop the RF handshake entirely rather than resuming it on power restore. The receiver holds the last sync state but will not re-establish the link automatically if the transmitter comes back on a different power cycle. Power the receiver off, then back on after the transmitter has fully booted. This forces a fresh sync sequence and restores the wireless link.