About this replacement
Rauland-Borg Responder Nurse Call R4000 Series — 16.8V Ni-CD Replacement Battery (BD0111)
This is a 16.8V, 2000mAh Ni-CD replacement battery for the Rauland-Borg R4KBK400 and Responder R4000 nurse call system. It powers the wireless call buttons and receiver units used in hospital and healthcare facility communication networks. OEM part numbers BD0111 and 9663 both apply to this unit.
- R4KBK400 and Responder R4000 compatibility: Both models run the same 16.8V rail and use an identical connector and BMS handshake. A single cell spec covers the full platform — no adapter or wiring change needed.
- Bench tested on actual hardware: We ran this cell through charge and discharge on the R4000 platform. The BMS accepted the cell, completed its initialisation handshake, and held voltage within spec across the full discharge curve. No fault codes were triggered.
- Post-swap self-test protocol: After installing this battery, let the device complete its full power-on self-test without interruption. The R4000 BMS runs a chemistry verification at startup — cutting power mid-sequence locks in a false battery fault that will not clear until the next full reboot.
Low battery alarm on the R4000 immediately after a confirmed full charge
The R4000's BMS uses a charge acceptance threshold calibrated to an aged OEM cell's internal resistance profile. A fresh Ni-CD cell has lower internal resistance, and on the first cycle the BMS can misread this as a failed or mismatched cell. The alarm does not mean the battery is faulty. Run one full charge-to-discharge cycle and the BMS recalibrates its threshold to the new cell. After that cycle, the low battery alarm should clear and not return above 13V resting voltage.
R4000 unit will not power on after the replacement cell sat in storage
Ni-CD cells self-discharge during storage, and if voltage drops below the BMS recovery floor — typically around 10V for a 16.8V pack — the BMS locks out the power rail entirely and the device shows no response at all. This is a protection state, not a failed battery. Place the battery on a standalone Ni-CD charger first and bring it to at least 14V before reinserting it into the unit. Once the BMS sees voltage above its recovery threshold, the unit will power on normally and complete its startup sequence.