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Mastervolt MLI-Ultra 12/1250 Lithium Ion Battery


The Ultra 12/1250 Lithium Ion battery boasts optimum performance even under harsh conditions, such as high charge and discharge currents, wet environments, mechanical shocks or vibrations. This is achieved by combining Lithium-Iron Phosphate (LiFePO4) cells with a proprietary Battery Management System (BMS) inside a sturdy, waterproof housing.

The Mastervolt BMS ensures optimal use of each individual cell. Integrated battery monitoring provides accurate and up-to-date information on the state of the battery. Integrated NMEA2000, CZone and MasterBus communication allows complete system integration, to ensure the best possible charging, while maximizing the lifetime of the battery.

Key Features

• Self-learning balancing algorithm: MLI Ultra batteries are equipped with a self-learning balancing algorithm that predicts the behaviour of each individual battery cell and balances proactively, resulting in a faster and more efficient charge cycle.

The self-learning system eliminates unnecessary stress on the cells, resulting in an even longer Battery Cycle Life.

• Freezing cold weather performance: This 1250 model comes with integrated thermal heat-pad and sophisticated low-temperature control to ensure maximum charging performance at freezing temperatures.

In cold weather it uses the connected charger to power the heat-pad and keep the battery cell temperature above freezing point. This assures the fastest possible charging and full power capabilities even on the coldest days.

 • Integrated battery switch: The integrated battery safety switch disconnects the battery cells in case of abnormalities. This is based on smart algorithms analysing all details of the battery condition such as charge current, temperature and cell details.

Where other integrated switches have current limitations, the MLI Ultra 1250 will keep providing energy up to 200 Amps continuously.

 • Plug-and-play by Auto Configuration: Wire the MLI Ultra 1250 to any supported Mastervolt charger, connect the communication cable and the battery automatically fully configures the charger to match the battery.

Product Content

- MLI Ultra battery with 2 x M8 bolt + washer + spring washer, for screw connection

- 1 x automotive battery pole positive (thick) + M8 Allen bolt, for clamp connection

- 1 x automotive battery pole negative (thin) + M8 Allen bolt, for clamp connection

- Handle

- 2 x Attachment strap (for stationary applications only)

- MasterBus terminator

- MasterBus cable (1m)

- Drop cable CZone/MB (1m)

- Auxiliary cable (2m)

- Quick installation manual


- Nominal battery voltage: 12V

- Nominal battery capacity: 100 Ah

- Nominal battery energy capacity: 1250 Wh

- Cycle life: 3500 cycles at 80 % DOD at 25 ⁰C, max. C3 charge and C2 discharge

- Max. charge current: 100 A

- Recommended charge current: ≤ 50 A

- Max. continuous discharge current: 200 A

- Continuous charge current: 100 A

- Peak discharge current: 500 A (10 sec.)

- Battery monitoring: Integrated

- MasterBus communication: yes

- CZone / NMEA 2000 communication: yes

- Terminals: M8

- Mounting position: Upright (recommended) or either long side

- Compliance: CE, E-Mark, UL1642 (cells only), FCC, RVIA compliant

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