About this replacement
Simonson-Wheel Defibrillator DMS730 / 750 — 12V Ni-MH Replacement Battery (88888624)
This is a 12V, 4000mAh Ni-MH battery for the Simonson-Wheel Defibrillator DMS730 and Defibrillator 750. It replaces OEM part numbers 88888624 and 110078. This battery supplies the stored charge the unit draws to deliver therapeutic defibrillation shocks during cardiac emergencies.
- DMS730 and 750 platform fit: Both models share the same 12V battery bay, connector pinout, and BMS handshake protocol. One cell fits both units without modification.
- Bench tested on actual hardware: We ran this cell through the DMS730 charge cycle and monitored BMS communication. The protection circuit accepted the charge profile and reported state-of-charge correctly after one full cycle.
- Post-installation self-test protocol: After fitting this battery, allow the defibrillator to complete its full power-on self-test without interruption. The BMS runs a capacity verification at startup — cutting power mid-sequence registers a false battery fault that persists until the next clean reboot.
Device not completing boot sequence after battery swap
The DMS730 runs a multi-stage BMS verification on every cold boot. A new Ni-MH cell that has been in storage will often present a lower resting voltage than the BMS threshold expects — typically below 10.8V. The unit interprets this as a depleted or failed pack and halts the boot sequence before reaching the ready state. Charge the replacement battery fully before installation, then allow the unit to complete its self-test uninterrupted.
Low battery alarm triggers immediately after a confirmed full charge
Ni-MH cells fresh from storage have not yet stabilised their internal resistance, which causes the BMS to read a lower effective capacity than is actually present. The DMS730's alarm threshold is calibrated to OEM cell characteristics, and a new cell can fall just below that threshold on its first discharge cycle. Run one complete charge-discharge cycle before relying on the charge indicator. After the first full cycle, the BMS recalibrates and the alarm clears at a resting voltage above 12.0V.