Meet the Mastervolt BI1203 BI Series Battery Isolator — a compact, fully solid-state solution engineered to split charge current with minimal energy loss across three battery outlets. Designed for 12 V or 24 V systems, it keeps battery banks independent while ensuring reliable charging from your charger or alternator.

• Three battery outlets for independent charging and optimal battery management.
• Max output — 80 A from the charger and 120 A from the alternator, providing robust support for multi-battery installations.
• Diode technology with voltage drop compensation — diode drop (~0.6 V) is automatically compensated by the connected charger/alternator output, maintaining efficient charging.
• Automatic voltage drop compensation is standard with Mastervolt Mass battery chargers and Alpha Pro regulators, ensuring consistent performance.
• Compact, fully solid-state design with corrosion-proof material and aluminium heat sinks, delivering long life and minimal wear.
• Easy installation thanks to molded diode splitters, end plates with connection lugs, and solid bolt connections with nuts and locking rings.
• Battery Watch / Charge Mate functionality to monitor battery condition and, when needed, act as a main switch for simplified system control.
• Versatile in 12/24 V systems, ideal for onboard systems with two or more batteries that must be charged independently for reliability.
• Dimensions & weight — 8.1 x 5.5 x 3.1 in and weight about 2.9 lb (approx. 1.3 kg). The BI range typically spans 580–1,300 g depending on configuration.

Engineered to protect and optimize marine, RV, or off-grid battery installations, the Mastervolt BI1203 BI Series Battery Isolator minimizes energy loss while providing dependable battery isolation and monitoring. Invest in smarter power management and extend your battery life with Mastervolt.