Welch-Allyn 72610 Otoscope Replacement Battery 2.4V 1800mAh

Welch-Allyn Compact Otoscope 93400 — 2.4V Ni-MH Replacement Battery (72610)

This is a 2.4V 1800mAh Ni-MH rechargeable battery for the Welch-Allyn Compact Otoscope 93400 and Compacset 93400. The otoscope is a handheld clinical instrument used to examine the ear canal and eardrum. It draws power from a small rechargeable cell housed in the handle, and this battery matches the OEM voltage, chemistry, and form factor.

• Compact Otoscope 93400 and Compacset 93400 fit: Both models share the same 2.4V Ni-MH cell specification, handle connector, and BMS handshake. The same battery seats correctly in either device without adapter or modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the 93400 platform. The BMS accepted the new cell on the first cycle, held the low-battery threshold, and did not trigger a false fault after full charge.
• Post-swap startup protocol: After installing this battery, let the device complete its full power-on self-test without interrupting it. The 93400 runs a BMS verification check at startup — cutting power mid-sequence flags a false battery fault that sticks until the next clean reboot.

Low battery alarm firing on the 93400 with a fully charged replacement

The 93400 BMS stores a charge profile calibrated to the original OEM cell. A new Ni-MH cell has a slightly different internal resistance curve, and the BMS reads that as a low state of charge on the first few cycles. This is not a fault with the battery — the BMS learn cycle has not completed yet. Run one full charge-discharge cycle before using the device clinically. After that cycle, the BMS recalibrates and the alarm clears.

93400 not powering on after the replacement cell sat in storage

Ni-MH cells self-discharge during storage, and if the cell voltage drops far enough, the BMS enters a protection state and blocks normal startup. The device appears dead even though the battery is physically intact. Place the battery in the OEM charger and allow a full charge cycle to complete — do not interrupt it. Once voltage recovers above the BMS recovery threshold of approximately 2.0V, the device will power on normally.