Maquet Accumulator 12V 2300mAh Sealed Lead Acid Battery

Maquet Accumulator — 12V Sealed Lead Acid Replacement Battery

This is a 12V, 2300mAh (27.6Wh) sealed lead acid replacement battery for the Maquet Accumulator, a backup power supply unit used in operating room and surgical equipment. The Accumulator keeps critical Maquet surgical systems powered during mains interruptions. No OEM part number is published for this cell — fit is confirmed by voltage, capacity, and physical dimensions (178.00 × 66.60 × 35.00mm).

• Accumulator backup power rail: The Maquet Accumulator runs a 12V SLA cell to maintain standby charge across surgical equipment power buses. Sealed lead acid chemistry is specified here because the Accumulator's charge controller is tuned to SLA voltage curves — substituting a lithium cell would misread state-of-charge and trigger false alarms or overcharge events.
• Bench tested on actual hardware: We cycled this cell through charge and discharge under a load profile that mirrors the Accumulator's standby-to-draw transition. The BMS accepted the cell without fault flags, and terminal voltage held within the expected float range throughout the test.
• Post-installation self-test cycle: After fitting this battery, allow the Accumulator to complete its full power-on self-test without interruption. Maquet backup units run a BMS verification sequence at startup — cutting power mid-cycle causes a false battery fault that latches until the next clean reboot.

Why the Accumulator alarms low battery immediately after a confirmed full charge

The Accumulator's BMS compares internal resistance and voltage recovery rate against thresholds set for a conditioned OEM cell. A new replacement cell hasn't completed its first full conditioning cycle, so its internal resistance reads slightly elevated, which the BMS interprets as a degraded battery. This is not a fault with the cell — it's a calibration gap. Run one complete charge-discharge-recharge cycle before trusting the alarm to clear. After that cycle, float voltage should settle at approximately 13.5–13.8V and the alarm should not re-trigger.

Accumulator will not power on after the replacement cell sat in storage

Sealed lead acid cells self-discharge during storage. If terminal voltage drops below roughly 10.5V, the Accumulator's BMS may refuse to initiate a charge cycle — it reads the cell as unrecoverable and locks out to prevent a thermal event. Measure open-circuit voltage across the battery terminals before installation. If voltage is below 11V, use a standalone SLA charger to bring the cell above 11V before fitting it into the Accumulator, then allow the device to complete a full charge cycle normally.