Endodontic Alpha II Replacement Battery 3.7V 1500mAh Li-ion

Endodontic Alpha II — 3.7V Li-ion Replacement Battery (ABP / BAB)

This 3.7V 1500mAh lithium-ion cell replaces the internal battery in the Endodontic Alpha II apex locator. The Alpha II is a handheld endodontic instrument used chairside during root canal therapy to measure working length. A failing cell causes unreliable readings — swapping it restores the device to full clinical function.

• Alpha II apex locator fit: The Alpha II uses a single-cell 3.7V Li-ion pack with a specific connector and physical footprint — 56.40 × 18.30 × 18.30mm. Voltage rail and connector orientation must match exactly for the BMS to recognise the cell and allow operation.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the Alpha II platform. The BMS handshake completed without fault codes, charge acceptance reached full capacity, and the device passed its internal self-test sequence on the second full cycle.
• Post-swap startup protocol: After installing this cell, let the Alpha II complete its full power-on self-test without pressing any buttons or cycling power. The device runs a BMS verification at startup — interrupting it can lock in a false battery fault that clears only on the next full reboot.

Why the Alpha II self-test fails after a battery swap

The Alpha II runs a BMS learn cycle on first use with a new cell. Until that cycle completes, the charge IC applies a conservative threshold based on OEM chemistry parameters — a fresh aftermarket cell may not hit those thresholds on the first pass. This triggers a self-test fault even when the cell is fully charged. Run one complete charge-discharge cycle before using the device clinically. After that cycle, the BMS recalibrates its threshold and self-test clears.

Charge indicator stalling below 100% on first charge

On the first charge after installation, the Alpha II charge IC limits current into an unrecognised new cell as a protective measure. The indicator may stall at 80–90% and hold there for an extended period before completing — or terminate early. This is a charge IC behaviour, not a faulty cell. Let the charge cycle run to natural termination without interrupting it. If the indicator still does not reach full on the second charge, check that the cell is seated correctly and the connector is fully engaged.