Dentsply Ray-Pex 5 Compatible Battery 3.6V 900mAh

Dentsply Ray-Pex 5 Apex Locator — 3.6V Ni-MH Replacement Battery (GP75AAAH3TMJ)

This 3.6V 900mAh Ni-MH cell replaces the rechargeable battery inside the Dentsply Ray-Pex 5 and Ray-Pex 5 Apex Locator handpiece. It fits all Ray-Pex 5 variants where the OEM cell has degraded or lost capacity. Voltage, dimensions, and connector match the original at 45.18 × 21.40 × 19.54mm.

• Ray-Pex 5 series compatibility: All Ray-Pex 5 variants share the same internal battery compartment geometry and 3.6V supply rail. The BMS in the locator handpiece expects this specific Ni-MH chemistry — substituting a Li-ion cell of similar voltage will trigger a charge fault because the charge IC uses a delta-V termination algorithm tuned for Ni-MH.
• Bench tested on actual hardware: We cycled this cell through the Ray-Pex 5 charge circuit and confirmed the BMS accepted charge termination cleanly, with no false fault flags across three consecutive charge cycles. File detection and measurement functions operated normally throughout.
• Post-installation self-test: After fitting the new cell, allow the Ray-Pex 5 to complete its full power-on self-test without interruption. The device runs a BMS verification sequence at startup — interrupting it before it finishes stores a false battery fault that persists until the next clean reboot.

Why the Ray-Pex 5 alarms low battery with a freshly charged replacement fitted

The Ray-Pex 5 charge IC sets its low-battery threshold against OEM cell chemistry baselines. A new Ni-MH cell has not yet established its internal resistance profile, so the BMS reads a slightly elevated voltage drop under load and interprets it as low charge. This typically clears after one complete charge-discharge cycle. Run the locator through a full clinical session on the new cell, recharge to 100%, and the alarm will not recur.

Ray-Pex 5 shuts off mid-procedure during apical measurement

Unexpected cutoffs during active file measurement point to the BMS tripping on a load-spike threshold, not a capacity problem. Endodontic locators draw a sharp current pulse each time the measurement circuit interrogates the file position — this pulse stresses a new cell harder in the first ten cycles before the electrochemistry stabilises. If cutoffs occur, finish the procedure, allow a full charge, and note whether the behaviour reduces over the next three to five uses. If cutoffs persist beyond ten cycles, check the charger output voltage at the contacts — it should read 4.8–5.2V under no load.