ProMariner 70A Single Alternator 2-Battery Isolator

The ProMariner 70A Single Alternator 2-Battery Isolator charges two banks from one alternator, with gold-plated terminals.

Seventy amps suits a smaller boat with a standard alternator rather than a high-output charging system. Fitting this behind a 130A alternator makes the isolator the bottleneck, and the alternator will never deliver what it is capable of.

Keeping the banks separated means a heavily discharged house or accessory bank cannot pull the starting battery down with it. That is the single thing an isolator is for, and it is why a starting battery on a properly isolated system still cranks after a long weekend at anchor.

Gold-plated terminals support dependable high-current connections in a damp engine space. The isolator should be sized against the alternator's output rather than the battery capacity behind it. Explore more battery isolators and charging relays.

• 70A suits a standard alternator, not high output
• Behind a 130A alternator it becomes the bottleneck
• A discharged house bank cannot pull the starter down
• Size against alternator output, not battery capacity