About this replacement
Welch-Allyn Spot Vital Signs Monitor — 3.6V Ni-Cd Replacement Battery (72250)
This 3.6V 1800mAh Ni-Cd battery replaces the original power cell in the Welch-Allyn Spot Vital Signs Monitor, Lumi View, and Ophthalmoscope. It matches the OEM form factor and connector, so no modification is needed for installation. Capacity is 6.48Wh — use the product data figure, not third-party sources.
- Spot Monitor, Lumi View, and Ophthalmoscope compatibility: These three devices share the same 3.6V Ni-Cd cell format, connector pinout, and BMS handshake protocol — that's why one part number covers all three platforms.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the Spot Monitor platform. The BMS accepted the cell on first insertion, completed its self-test sequence without fault codes, and logged correct state-of-charge data from cycle one.
- Post-swap startup protocol: After installing this battery, let the device complete its full power-on self-test without pressing any buttons or interrupting the boot sequence. The Spot Monitor runs a BMS verification routine at startup — cutting power during this window writes a false battery fault that persists until the next clean reboot.
Why the Spot Monitor shows a low-battery alarm immediately after a confirmed full charge
The Spot Monitor's BMS holds a chemistry-calibrated threshold table loaded for the OEM cell's aged charge profile. A brand-new Ni-Cd cell presents a slightly different internal resistance signature on first insertion, which the BMS interprets as below the minimum acceptable state-of-charge. This is not a fault with the cell. Run one complete charge-discharge cycle and the BMS recalibrates its threshold to the new cell's actual profile — the alarm clears after that first full cycle.
Device will not power on after the replacement cell sat in storage
Ni-Cd cells self-discharge during storage. If voltage has dropped below the Spot Monitor's BMS recovery threshold — typically around 3.0V for a 3.6V pack — the device will not boot, and the charge indicator may show no activity. Place the battery on charge for a minimum of 30 minutes before attempting power-on. If the charge IC still shows no activity after 30 minutes, disconnect, wait 60 seconds, and reconnect to trigger the recovery charge mode.