About this replacement
VDW Raypex 6 Apex Locator — 2.4V Ni-MH Replacement Battery (SM-BP-V2.4-DP)
This 2.4V, 2000mAh Ni-MH cell replaces the internal rechargeable battery in the VDW Raypex 6 apex locator. The Raypex 6 uses this battery to power its impedance-based root canal measurement circuit during endodontic procedures. Capacity matches the OEM specification at 4.8Wh.
- Raypex 6 platform fit: The Raypex 6 apex locator uses a fixed-form Ni-MH cell at 2.4V to match the voltage rail driving the measurement and display circuits. Swapping to a different voltage or chemistry will cause the charge IC to reject the cell or produce inaccurate impedance readings.
- Bench tested on actual hardware: We cycled this cell through the Raypex 6 charge IC and confirmed the BMS completed its self-test handshake. The protection circuit tripped correctly at low-voltage cutoff and recovered cleanly on the following charge cycle.
- Post-installation self-test requirement: After fitting this cell, allow the Raypex 6 to complete its full power-on self-test without interruption. The device runs a BMS verification sequence at startup — cutting power during this window writes a fault flag that persists until the next clean reboot.
Why the Raypex 6 BMS rejects a new cell on the first charge cycle
The Raypex 6 charge IC applies a chemistry-specific acceptance threshold calibrated to a cell that has already completed at least one full charge-discharge cycle. A brand-new Ni-MH cell presents a slightly different internal resistance profile than a conditioned cell, which can cause the IC to limit charge current or flag an early termination. This is not a fault with the replacement cell — it is the charge controller applying a conservative first-cycle limit. Run one complete charge-discharge cycle before using the device clinically.
Low battery alarm triggering mid-procedure on a freshly charged cell
The Raypex 6 monitors terminal voltage under load during active measurement. In the first several cycles, a new Ni-MH cell has not yet reached full electrolyte activation, so internal resistance is higher than it will be once conditioned. Under the device's measurement load, the terminal voltage dips enough to cross the low-battery threshold even when the cell is substantially charged. Complete five to ten full charge-discharge cycles and the terminal voltage sag will stabilise. If the alarm persists after ten cycles, check resting voltage — a healthy conditioned cell should read above 2.2V at rest.