CONTEC CMS9000 Patient Monitor Replacement Battery 7.4V 3700mAh

CONTEC CMS9000 / CMS7000 Patient Monitor — 7.4V Li-ion Replacement Battery

This 7.4V 3700mAh Li-ion battery replaces the internal cell in CONTEC CMS9000 and CMS7000 patient monitors. It fits the portable vital signs monitoring units used across hospital wards, clinics, and emergency transport settings. Voltage and capacity match the original specification to keep the monitoring device operational during battery degradation or cell replacement cycles.

• CMS9000 and CMS7000 platform fit: Both monitor lines share the same 7.4V two-cell Li-ion pack architecture, connector pinout, and BMS communication protocol — which is why one replacement cell covers both series. Swapping between models does not require firmware changes or hardware modification.
• Bench tested on actual hardware: We cycled this cell through the CMS9000 charge circuit and confirmed the BMS handshake completed without a battery fault flag. The charge IC accepted the cell and terminated at full capacity on the first supervised cycle.
• Post-installation self-test protocol: After fitting this battery, let the CMS9000 complete its full power-on self-test without interrupting the boot sequence. The device runs BMS verification at startup — cutting power during this window triggers a false battery fault that persists until the next clean reboot.

CMS9000 alarming low battery immediately after a confirmed full charge

The CMS9000 BMS uses a charge-state threshold calibrated to the OEM cell's internal resistance profile. A new replacement cell has a slightly different impedance signature on the first cycle, which causes the BMS to read state-of-charge conservatively and trip the low battery alarm even at full voltage. This is not a defective cell — it resolves after one complete charge-discharge cycle that allows the BMS to re-map the cell's actual capacity curve. Run one full cycle before placing the unit back into clinical rotation.

CMS9000 will not power on after the replacement battery sat in storage

Li-ion cells self-discharge during storage, and if voltage drops below approximately 2.5V per cell — 5.0V at the pack level — the CMS9000's BMS enters deep-discharge lockout and blocks power-on entirely. The device will appear completely dead even though the cell is not damaged. Place the battery on charge inside the monitor for a minimum of two hours before attempting to power on; the charge IC applies a low-current pre-charge recovery mode below that voltage threshold. Once the pack climbs above 6.0V, normal charging and boot resume.