The Mastervolt BI1202-S BI Series Battery Isolator is a compact, fully solid-state solution that divides your charge current with minimal energy loss. Designed for dual-battery installations on 12 or 24 V systems, it keeps two battery banks charged independently while sharing the same charging source. The BI1202-S integrates the Charge Mate feature for connecting and/or disconnecting two batteries, and Battery Watch for monitoring battery health (also usable as a main switch).

Key advantages

• Two battery outlets for independent charging paths
• Max output from the charger up to 80 A and from the alternator up to 120 A
• Diode-based technology with voltage drop compensation (0.6 V) to maximize charging efficiency
• Automatic voltage drop compensation supported by Mastervolt Mass chargers and Alpha Pro regulators
• Solid-state construction, compact design, and corrosion-proof housing with aluminum heat sinks
• End plates with connection lugs and bolt connections with nuts and locking rings for easy installation
• Completely encapsulated electronics and molded diode splitters for durability

Specifications at a glance

• Number of battery outlets: 2
• Dimensions (HxWxD): 8.1 x 5.5 x 3.1 inches
• Weight: 2.6 kg
• Max output charger: 80 A
• Max output alternator: 120 A
• Compensation diode: Yes

Designed for boats, caravans, and any multi-battery electrical system, the BI1202-S ensures reliable, efficient charging while protecting each battery bank. If you’re looking to simplify dual-battery charging with a robust, low-maintenance isolator, this Mastervolt model delivers.