Biolight M800 Patient Monitor Compatible Battery 3.7V 1700mAh

Biolight M800 — 3.7V Li-ion Replacement Battery (12-100-0002)

This 3.7V, 1700mAh Li-ion battery replaces the original cell in the Biolight M800 patient monitor and the Yonker YK-8000C. It fits the OEM slot directly, matching the original part numbers 12-100-0002 and LB-03. The M800 uses this cell to power continuous SpO2, heart rate, and temperature monitoring in clinical and home healthcare settings.

• M800 and YK-8000C compatibility: Both devices share the same 3.7V single-cell architecture, connector pinout, and BMS handshake protocol — the battery communicates charge state directly to the monitor's charge IC using the same data line on both platforms.
• Bench tested on actual hardware: We cycled this cell through the M800's full charge-discharge profile and confirmed the BMS reported accurate state-of-charge across the full voltage range, with no false low-battery flags after the first complete cycle.
• Post-installation self-test: After fitting this battery, let the M800 complete its full power-on self-test without interruption. Medical device firmware runs a BMS verification at boot — cutting power mid-sequence triggers a persistent battery fault that won't clear until the device completes a clean, uninterrupted reboot.

M800 alarming low battery immediately after a confirmed full charge

The M800's charge controller sets its low-battery alarm threshold against a stored cell profile calibrated to the original OEM chemistry. A new replacement cell doesn't match that profile until the BMS completes at least one full charge-discharge learn cycle. On the first boot, the monitor reads the new cell's open-circuit voltage and applies a conservative safety margin, which can trigger a low-battery alarm even at 95–100% actual charge. Run one complete charge-discharge cycle before using the device clinically — after that cycle, the BMS recalibrates and the alarm clears.

M800 won't power on after the replacement battery sat in storage

Li-ion cells self-discharge during storage. If this battery shipped or sat unused long enough, its resting voltage may have dropped below the M800's BMS recovery threshold — typically around 3.0V — causing the monitor to refuse to boot entirely. Connect the device to mains power and leave it on charge for a minimum of 30 minutes before attempting to power on. This allows the charge IC to trickle-charge the cell back above the BMS wake threshold. If the monitor still won't respond after 30 minutes on charge, confirm the charger is supplying voltage at the dock contacts before assuming a cell fault.