Mastervolt MLI Ultra 12V 100Ah: Premium Lithium Power for Harsh Environments

The Mastervolt 66011250 MLI Ultra 12V / 1250Wh / 100Ah lithium battery is engineered for users who demand maximum reliability, safety, and performance from their energy storage. Designed for the harshest operating environments, the MLI Ultra series delivers consistent power whether installed in recreational, commercial, or emergency systems.

As part of the trusted Mastervolt lineup, the MLI Ultra is built around advanced LiFePO₄ chemistry, a proprietary Battery Management System, and a rugged, fully waterproof housing.

👉 Product page: https://www.12voltpower.com/product/mastervolt-66011250-mli-ultra-12v-100ah-lithium-battery/

Heavy-Duty Lithium Performance Without Compromise

The MLI Ultra series is designed to operate reliably under conditions that challenge conventional batteries. High charge and discharge currents, vibration, moisture, and mechanical shock are all accounted for in its construction.

Key design elements include:

• High-quality Lithium-Iron Phosphate (LiFePO₄) cells
• Proprietary Mastervolt Battery Management System (BMS)
• Sealed, waterproof enclosure for harsh environments

This combination allows the battery to deliver extreme performance while maintaining long-term safety and durability.

Intelligent BMS with Full System Integration

At the heart of the MLI Ultra is a sophisticated Battery Management System that continuously monitors and optimizes each individual cell. Integrated battery monitoring provides real-time insight into:

• Battery voltage
• Current flow
• State of charge
• Remaining runtime

Built-in communication support allows seamless integration with:

• MasterBus
• CZone
• NMEA 2000

This enables coordinated charging, advanced monitoring, and system-wide optimization when paired with compatible Mastervolt chargers and displays.

Self-Learning Balancing for Extended Battery Life

The MLI Ultra batteries feature a self-learning balancing algorithm that predicts individual cell behavior and proactively balances the battery during operation. This results in:

• Faster and more efficient charging cycles
• Reduced stress on individual cells
• Extended battery cycle life

By actively managing cell behavior, the system maximizes usable capacity while preserving long-term performance.

Reliable Charging in Freezing Conditions

Cold temperatures can limit lithium battery performance, but the MLI Ultra 1250 is designed to operate even in freezing environments. An integrated thermal heat-pad and intelligent temperature control system keep battery cells above freezing during charging.

When temperatures drop, the connected charger powers the heat-pad automatically, ensuring:

• Safe charging in cold conditions
• Full power availability
• Faster charge recovery in winter environments

This makes the battery well-suited for year-round use in mobile and outdoor installations.

Integrated Battery Safety Switch with High Current Capability

An integrated battery safety switch protects the system by disconnecting the battery in the event of abnormal operating conditions. Smart algorithms continuously analyze charge current, temperature, and cell data.

Unlike conventional integrated switches, the MLI Ultra 1250 continues to deliver:

• Up to 200 amps continuous output
• Stable power delivery under heavy loads

This allows the battery to support demanding applications without sacrificing protection.

Plug-and-Play Installation with Auto Configuration

Installing lithium power is simplified with automatic configuration. When connected to a supported Mastervolt charger and communication cable, the battery automatically configures the charging system to match its requirements.

Benefits include:

• No manual charger programming
• Smooth, worry-free charging setup
• Optimized charging profiles out of the box

This plug-and-play approach reduces installation time and eliminates configuration errors.

Designed for Efficiency, Space, and Longevity

The MLI Ultra 12V 100Ah battery is engineered as a drop-in replacement for Group 31 and Group 49 batteries while delivering significantly higher performance.

Key advantages:

• More than three times the lifespan of traditional batteries
• Up to 70% savings in space and weight
• High charge and discharge rate up to 2C
• Fast charging in as little as 60 minutes
• Series connection possible up to 48V

Built for Certified Safety and Compliance

The MLI Ultra meets rigorous international safety and compliance standards, including:

• UN 38.3
• CE, E-Mark, FCC
• UL1973 and RVIA
• TEI listing

This ensures suitability for regulated environments and professional installations.

Specifications at a Glance

• Capacity: 1250 Wh / 100 Ah
• Nominal Voltage: 12V
• Weight: 29 lbs
• Dimensions: 12.9 × 6.75 × 7.6 in
• Chemistry: LiFePO₄
• Fully waterproof construction

Genuine Mastervolt Lithium Solutions from 12VoltPower.com

12VoltPower.com offers authentic Mastervolt lithium batteries and power solutions, ensuring compatibility, safety, and long-term performance across marine, mobile, and off-grid power systems.