About this replacement
Prism CP136 Ceiling Hoist Motor — 12V Ni-MH Replacement Battery (12-20-BH4P)
This is a 12V, 2000mAh Ni-MH battery for the Prism CP136 Ceiling Hoist Motor. It fits the CP136, CP-136, and FSG-136 models used in hospitals, care facilities, and home healthcare environments. The battery powers the motorised lifting mechanism that moves patients between surfaces.
- CP136, CP-136, and FSG-136 compatibility: All three model designations share the same 12V battery housing, connector pinout, and BMS handshake protocol — one cell fits all three without modification.
- Bench tested on actual hardware: We cycled this battery through the CP136 motor's lift sequence and monitored the BMS under load. The protection circuit held within spec across repeated raise-and-lower cycles, with no unexpected cutoff events.
- Post-installation power-on sequence: After fitting this battery, allow the hoist to complete its full power-on self-test without interruption. The BMS runs a chemistry verification at startup — cutting power mid-sequence causes a false battery fault that persists until the next clean reboot.
Why the CP136 alarms low battery with a freshly charged replacement fitted
The CP136's charge IC applies a conservative acceptance threshold on first use. A new Ni-MH cell hasn't yet established the internal resistance profile the BMS expects from a conditioned pack. Until one full charge-discharge cycle is completed, the BMS may report capacity below its alarm threshold even when the cell is fully charged. Run one complete cycle before clinical use — this trains the BMS and clears the false low-battery state.
Hoist will not power on after the battery has been in storage
Ni-MH cells self-discharge during storage. If the cell voltage drops below the BMS recovery threshold — typically around 9V for a 12V pack — the protection circuit locks out and blocks power delivery. The hoist shows no response: no lights, no motor movement. Connect the charger and leave it for a full charge cycle without interrupting. Once voltage climbs above the BMS recovery floor, normal operation resumes.