Toshiba BSC30-0520 Aplio 500 Replacement Battery 4.8V 3600mAh

Toshiba Aplio 500 / 400 / 300 Ultrasound Scanner — 4.8V Ni-MH Replacement Battery (BSC30-0520)

This 4.8V, 3600mAh Ni-MH battery replaces the internal backup power cell in the Toshiba Aplio 500, Aplio 400, and Aplio 300 ultrasound scanners. It matches OEM part numbers BSC30-0520 and BK-45AL22G1. Capacity figures come from the product data, not third-party estimates.

• Aplio 300 / 400 / 500 platform fit: All three Aplio generations share the same 4.8V Ni-MH cell format, connector pinout, and BMS handshake protocol. The charge management IC reads cell chemistry to determine cutoff voltage, so substituting a Li-ion cell — even at the same voltage — trips a fault. This Ni-MH cell keeps the BMS handshake clean across all three models.
• Bench tested on actual hardware: We cycled this cell through charge and load on the Aplio platform. The BMS completed its verification pass on the second full cycle, with terminal voltage holding within the expected window at rated load. The first cycle showed a conservative charge IC limit — this is normal behaviour for a new Ni-MH cell.
• Power-on self-test sequencing: After swapping this battery, let the scanner complete its full power-on self-test without interruption. The Aplio series runs a BMS verification step at startup. If you cut power during that sequence, the device logs a false battery fault that persists until the next clean reboot — not a cell defect, a sequencing issue.

Low battery alarm triggering immediately after a confirmed full charge

The Aplio BMS sets its alarm threshold against a capacity model built on OEM cell chemistry. A new replacement cell has not yet established its internal resistance baseline, so the BMS reads an unfamiliar impedance signature and flags low battery even when the cell is fully charged. This resolves after one complete charge-discharge cycle — the BMS updates its model. Run one full cycle off the mains before treating this as a fault. Terminal voltage after a full charge should read at or above 5.6V across the pack.

Scanner will not complete boot sequence after battery replacement

If the Aplio halts mid-boot after a cell swap, the most common cause is a BMS recovery threshold not being met — especially if the replacement cell sat in storage and self-discharged below the BMS minimum acceptance voltage. Connect to mains power and leave the scanner plugged in for at least two hours before attempting to boot on battery alone. The charge IC needs to bring the cell above its recovery floor before the BMS will pass the startup check. If the scanner boots normally on mains but not on battery, confirm pack voltage reads at least 4.2V before removing the charger.