CONTEC CMS8000 ICU Monitor Replacement Battery 7.4V 10400mAh

CONTEC CMS8000 / MEDITECH M8000S — 7.4V Li-ion Replacement Battery (855183P)

This 7.4V, 10400mAh (76.96Wh) lithium-ion battery replaces OEM part 855183P in the CONTEC CMS8000 ICU Patient Monitor and the MEDITECH M8000S monitor. Both devices share the same voltage rail, connector, and BMS handshake protocol, making a single cell compatible across both platforms. Capacity figures come from the product data — not extrapolated from web sources.

• CMS8000 and M8000S platform fit: These two monitors share an identical battery bay, 7.4V power rail, and BMS communication protocol. The cell slots in and the monitor firmware recognises it through the same handshake it uses with the OEM pack — no jumpers or firmware changes required.
• Bench tested on actual hardware: We ran this cell through full charge-discharge cycles on a CMS8000 unit. The BMS completed state-of-charge calibration on the second cycle and passed all internal resistance thresholds. Alarm suppression activated correctly at expected voltage steps.
• Power-on self-test after installation: After fitting this battery, allow the CMS8000 to complete its full boot sequence without interruption. The monitor runs a BMS verification pass at startup — cutting power mid-sequence leaves a false battery fault flag in memory that persists until the next clean full reboot.

CMS8000 not completing boot sequence after battery swap

The CMS8000 boot sequence includes a BMS handshake that reads cell voltage, internal resistance, and charge state before the monitoring software loads. A freshly installed replacement cell, particularly one that sat in storage, may present a resting voltage the device firmware classifies as borderline. This triggers a mid-boot halt rather than a clean alarm. Charge the battery fully before first installation — confirmed at 8.4V across the terminals — then allow the device to boot without interruption.

Charge indicator stuck below 100% on first full charge

The CMS8000 charge IC applies a conservative upper current limit on cells it has not yet profiled. On the first charge cycle, the IC terminates absorption phase early, leaving the displayed state-of-charge reading at 90–95% even after several hours on the charger. This is not a fault — the charge profile completes fully on the second cycle once the IC has logged internal resistance data from the first discharge. Run one complete charge-discharge-charge cycle before placing the monitor in clinical rotation.