Welch-Allyn VS100 Replacement Battery 10.8V 2600mAh

Welch-Allyn VS100 Vital Signs Monitor — 10.8V Li-ion Replacement Battery (34004 / 30018-EX)

This is a 10.8V, 2600mAh Li-ion battery for the Welch-Allyn VS100 portable vital signs monitor. It fits the VS100 used in clinical settings for blood pressure, SpO2, temperature, and pulse monitoring. Voltage and connector match the OEM specification for the 34004 and 30018-EX part numbers.

• VS100 platform fit: The VS100 draws from a fixed 10.8V three-cell Li-ion pack. Both OEM part numbers (34004 and 30018-EX) reference the same voltage rail and connector pinout, so this cell seats and communicates with the device BMS without modification.
• Bench tested on actual hardware: We ran this battery through charge and load cycles on the VS100 platform. The BMS handshake completed, charge acceptance was normal, and the device passed its internal power-on self-test without throwing a battery fault code.
• First-use self-test protocol: After installing this battery, let the VS100 complete its full power-on self-test without interruption. The device runs a BMS verification sequence at startup — cutting power mid-cycle registers as a battery fault that persists until the next clean reboot.

VS100 alarming low battery immediately after a confirmed full charge

The VS100's BMS compares internal cell telemetry against thresholds calibrated to the OEM cell's discharge curve. A new replacement cell has not yet completed a full learn cycle, so the BMS reads the curve as mismatched and triggers a low-battery alarm even at full charge. This is not a cell defect — it resolves after one complete charge-to-discharge cycle. Run the battery down to automatic shutdown, then charge fully before returning the unit to clinical use.

VS100 failing to power on after the battery sat in storage

Li-ion cells self-discharge during storage. If the pack voltage drops below approximately 9V, the VS100's BMS enters a protection state and blocks normal power-on to prevent damage to the cells. The fix is a slow pre-charge — connect the unit to mains power and leave it on charge for at least 30 minutes before attempting to power on. Once the BMS detects voltage above the recovery threshold, it exits protection and the device boots normally.