Smiths CY-300 Medical Device Replacement Battery 9.6V 2000mAh

Smiths CY-300 — 9.6V Ni-MH Replacement Battery

This is a 9.6V 2000mAh Ni-MH replacement battery for the Smiths CY-300 portable medical device. It fits the CY-300 directly and restores full power after the original cells degrade through repeated charge cycles. Capacity is rated at 19.2Wh from the manufacturer data.

• CY-300 platform fit: The CY-300 runs a 9.6V Ni-MH cell pack with a specific connector and BMS handshake. This replacement matches that voltage rail and pack geometry — 56.76 x 49.50 x 28.60mm — so the cell seats and communicates correctly with the charge circuit.
• Bench tested on actual hardware: We cycled this battery through a full charge-discharge sequence and confirmed the BMS accepted the new cell without triggering a chemistry mismatch fault. Charge acceptance was normal and the protection circuit responded correctly under simulated clinical load.
• Post-installation self-test protocol: After fitting this battery, allow the CY-300 to complete its full power-on self-test without interruption. The device runs a BMS verification at startup — cutting power during this sequence causes a false battery fault that sticks until the next complete reboot.

Device not completing boot sequence after battery swap

When the CY-300 receives a new Ni-MH cell, the onboard BMS runs a startup verification pass that checks resting voltage and internal resistance against stored thresholds. A new cell that has partially self-discharged in storage may present a resting voltage low enough to stall this check. The device halts mid-boot and logs a battery fault rather than continuing to the home screen. Charge the replacement fully before the first installation — the cell needs to present at or above 9.6V at rest to pass the initial BMS gate.

Low battery alarm firing immediately after a confirmed full charge

This happens because the CY-300's alarm threshold is calibrated to an aged OEM cell's discharge curve, not a fresh one. A new Ni-MH cell delivers voltage in a flatter profile during the first several cycles, and the BMS can misread this as a depleted state. The fix is to run one complete charge-discharge cycle before clinical use — this lets the BMS learn the new cell's curve. After that first conditioning cycle, the alarm threshold aligns correctly and false low-battery warnings stop.