About this replacement
Welch-Allyn Connex Spot Monitor — 7.4V Li-ion Replacement Battery (901000)
This 7.4V 3400mAh Li-ion battery replaces the original power cell in the Welch-Allyn Connex Spot and Connex Spot Monitor. It also fits Grason-Stadler and Pressure unit Connex Spot configurations. Cross-references include OEM part numbers 901000, BATT22, OM11878, and TM78370.
- Connex Spot platform fit: These monitor variants share the same 7.4V battery bay, connector pinout, and BMS handshake protocol. One cell covers the full platform without modification.
- Bench tested on actual hardware: We cycled this cell through charge, full load, and rest on the Connex Spot platform. The BMS accepted the cell, completed its verification handshake, and reported accurate state-of-charge across the full discharge curve.
- Post-install self-test protocol: After inserting this battery, allow the Connex Spot to complete its full power-on self-test without interruption. The device runs a BMS verification sequence at startup. Cutting power during this sequence logs a false battery fault that persists until the next clean reboot.
Device not completing boot sequence after battery swap
The Connex Spot runs a BMS learn cycle on first use with a new cell. If the device stalls mid-boot or returns a battery error, the BMS has not yet profiled the replacement cell's chemistry. This is not a fault with the cell. Run one full charge-discharge cycle before returning the unit to clinical use — the BMS will map the new cell's discharge curve and boot cleanly from the second cycle onward.
Charge indicator not reaching 100% on the first charge
On first installation, the Connex Spot's charge IC applies a conservative current limit to an unrecognised cell. This causes the indicator to plateau below 100% before the cycle completes. The cell is not defective. Disconnect the charger, power the device on briefly to drop the voltage slightly, then reconnect — the charge IC re-evaluates the cell and typically reaches full charge on the second attempt. Target resting voltage after a full charge should read approximately 8.3–8.4V at the battery terminals.