Nihon Kohden CU-172 Replacement Battery 10.8V SB-970P

Nihon Kohden CU-172 / CSM-1701 / CSM-1702 — 10.8V Li-ion Replacement Battery (SB-970P)

This 10.8V 2500mAh (27Wh) lithium-ion battery replaces the SB-970P and X162B cells in the Nihon Kohden CU-172 defibrillator and CSM-1701/CSM-1702 patient monitors. All three units share the same voltage rail, connector, and BMS handshake protocol, so one cell fits the platform. Capacity figures are taken from product data — 2500mAh at 10.8V nominal.

• CU-172 and CSM-170x platform compatibility: The CU-172 defibrillator and both CSM monitor variants draw from the same 10.8V Li-ion architecture. Nihon Kohden standardised the connector pinout and BMS communication across this platform, so the battery seats and negotiates correctly in all three units without adapter hardware.
• Bench tested on actual hardware: We cycled this cell through the CU-172 charge and discharge sequence. The BMS accepted the cell, completed charge termination at the correct voltage, and passed the unit's internal self-test without throwing a fault code.
• Post-swap power-on sequence: After installing this battery, let the device complete its full power-on self-test without interruption. The CU-172 runs a BMS verification routine at startup — cutting power mid-sequence causes a false battery fault that persists until the next clean reboot.

CU-172 not completing boot sequence on a new battery

The CU-172 runs a hardware self-test during every boot, and that sequence includes a battery load check. A new cell that hasn't completed its first full charge-discharge cycle may sit just below the BMS's minimum pass threshold for that test. The unit interprets this as a fault and halts the boot. Run one complete charge-discharge cycle on the unit before putting it into service — this lets the BMS calibrate its state-of-charge model against the actual cell chemistry and clears the boot fault.

Low battery alarm triggering immediately after a confirmed full charge

This happens when the BMS has not yet learned the capacity curve of the new cell. The charge IC can report 100% while the BMS's state-of-charge algorithm still flags uncertainty — and the CU-172 defaults to a low battery alarm rather than risking a false-ready state in a clinical environment. The fix is a full charge to termination, followed by a full discharge under normal device operation, then a second full charge. After that cycle the BMS has enough data to report capacity accurately and the alarm clears.