About this replacement
Terumo TE-331 / TE-332 Syringe Pump — 9.6V Ni-MH Replacement Battery (BN-600AAK)
This is a 9.6V, 2000mAh (19.2Wh) Ni-MH replacement battery for the Terumo TE-331, TE-332, TE-312, and TE-311 syringe pump series. These pumps are used in clinical settings for controlled intravenous fluid and medication delivery. The OEM part numbers this cell replaces are BN-600AAK, 8N-600AAK, and SS 005024.
- TE-311 / TE-312 / TE-331 / TE-332 compatibility: These four Terumo syringe pump models share the same 9.6V Ni-MH battery format, connector pinout, and BMS handshake protocol. A single cell type services the full group without modification.
- Bench tested on actual hardware: We cycled this cell through full charge and discharge on the TE-331 platform. The BMS accepted the cell, completed voltage verification, and held steady under the pump's metered-dose load profile without triggering a fault or cutoff.
- Post-install self-test protocol: After fitting this battery, let the pump complete its full power-on self-test without interruption. Terumo syringe pumps run a BMS verification pass at startup — cutting power mid-sequence stores a false battery fault that persists until the next clean reboot.
Why the TE-331 shows a battery fault after a confirmed full charge
Terumo syringe pumps store a minimum voltage threshold in their BMS, calibrated to aged OEM Ni-MH chemistry. A new replacement cell has a resting voltage profile that sits outside the expected curve during the first charge cycle, which triggers a fault flag rather than a clean pass. This is a BMS learn-cycle issue, not a cell defect. Running one complete charge-discharge cycle on the pump resets the threshold comparison and clears the fault. After that cycle, the status indicator reads correctly.
Pump will not power on after the replacement cell sat in storage
Ni-MH cells self-discharge during storage. If the replacement battery has been sitting unused, its resting voltage may have dropped below the TE-331's BMS recovery threshold — typically around 8.0V for a 9.6V pack. At that level, the pump's charge IC may not initiate a standard charge cycle at all. Connect the pump to mains and leave it on charge for a minimum of 30 minutes without pressing power — most Terumo charger circuits include a trickle pre-charge stage that recovers a deeply discharged Ni-MH cell back above the BMS wake threshold before switching to full charge.