About this replacement
Dentsply Smartlite Curer / SmartLite PS — 4.8V Ni-MH Replacement Battery (GP50NH4SMXZ)
This is a 4.8V 300mAh Ni-MH replacement battery for the Dentsply Smartlite Curer and SmartLite PS dental curing lights. Both devices use the same GP50NH4SMXZ cell pack and voltage rail. Capacity matches the original spec at 300mAh (1.44Wh).
- Smartlite Curer and SmartLite PS compatibility: Both models share the same 4.8V NiMH pack format, connector pinout, and BMS handshake. The GP50NH4SMXZ cell fits both without modification.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on a Smartlite unit and confirmed the BMS accepted the pack, completed its charge cycle, and held voltage within spec under load. No BMS rejection on any test unit.
- Post-swap self-test protocol: After installing this battery, allow the Smartlite to complete its full power-on self-test without interruption. Medical device BMS firmware runs a verification sequence at startup — cutting power during this window logs a false battery fault that persists until the next clean reboot.
Low battery alarm on the Smartlite immediately after a confirmed full charge
The Smartlite's charge IC compares cell voltage against a threshold calibrated to a conditioned OEM cell. A new NiMH pack fresh out of packaging has not yet completed a full charge-discharge cycle, so its resting voltage sits slightly below the BMS pass threshold. The device reads this as a low-charge state even when the pack is fully charged. Run one complete charge-discharge cycle before clinical use — after that cycle, the BMS registers the correct voltage floor and the alarm clears.
Smartlite will not power on after the battery has been sitting in storage
NiMH cells self-discharge during storage, and if the pack voltage drops below approximately 3.6V, the Smartlite's BMS enters a deep-discharge lockout state and refuses to power on. The fix is a slow recovery charge — place the unit in its dock and leave it charging for a full uninterrupted cycle without attempting to power on. Once cell voltage recovers above the BMS recovery threshold, the device will boot normally. If the dock charge indicator does not light at all, check dock contacts for oxidation before replacing the battery.