About this replacement
Medima P2 / P Infusion Pump — 9.6V Ni-MH Replacement Battery (AA-14.1S8)
This is a 9.6V, 2000mAh Ni-MH replacement battery for the Medima P2 and P infusion pump. It matches the OEM part number AA-14.1S8 and restores cordless operation when the original cell has degraded. Voltage and capacity are matched to the original specification — do not substitute a Li-ion cell in this device.
- P2 and P infusion pump compatibility: Both models share the same 9.6V Ni-MH voltage rail, connector pinout, and BMS handshake profile. The AA-14.1S8 part number covers both variants — no adapter or modification required.
- Bench tested on actual hardware: We cycled this cell through charge, load, and BMS handshake verification on compatible infusion pump hardware. The BMS accepted the cell on first insertion and reported correct voltage across the full discharge curve.
- Post-installation self-test requirement: After fitting this battery, allow the device to complete its full power-on self-test cycle without interruption. Infusion pumps run a BMS verification routine at startup — cutting power mid-sequence triggers a false battery fault that persists until a clean reboot from a full charge.
Low battery alarm on the P infusion pump immediately after a confirmed full charge
This happens because the pump's BMS is calibrated to an OEM cell that has completed multiple charge-discharge cycles. A new cell has not yet established the internal resistance profile the BMS uses to validate state-of-charge. On the first one to three cycles, the BMS may read the new cell as marginal and trigger the alarm even at full capacity. Run one complete charge-discharge cycle before relying on the battery in clinical use — after that, the alarm threshold should clear.
Medima P2 will not power on after the battery has been in storage
Ni-MH cells self-discharge at roughly 1–2% per day. A cell stored for several months can fall below the BMS recovery threshold — typically around 7.2V for a 9.6V pack — and the device refuses to boot. Place the battery on its charger for a full uninterrupted charge cycle before attempting to power on the pump. If the charger does not detect the cell, verify the terminal voltage with a multimeter — anything above 5V should accept a slow trickle charge to recover.