With 2/0 wire, as long as the house battery bank is kept within 12 feet of the starting battery, even at charging rates up to 149 amps, a 3% voltage drop will still be achieved. Most applications will never see amps that high nor are most alternators capable of putting out that many amps.

2/0 wire with 105☌ insulation under 50 feet in length is capable of handling currents of up to 330 amps. 2/0 wire will be enough for 95% of applications. Wire size for Battery Isolatorīlanket Statement: Use 2/0 wire. Lithium Battery Isolatorĭue to the resting voltage rates of Lithium Batteries, you’ll likely want a lithium battery specific Isolator.Īlthough a normal battery isolator shouldn’t ‘damage’ your lithium batteries, it simply may not disconnect properly when your engine is off as it may see the higher voltage of the lithium batteries as ‘charging’, which will keep the batteries combined. It will typically be stamped onto a metal plate on the alternator itself. The max amps your alternator will output can sometimes be found in the spec sheet of the vehicle. Size your battery isolator to handle the max amp output from your alternator. Although you’ll likely never see your full alternator output amperage going through your isolator, it’s really the only base line you’ve got. Your battery isolator will depend on the size of your alternator. This number is simply the amount of potential amps that could be flowing through the device from your alternator to your house battery bank. Most Battery isolators are rated in terms of amps. You can check that out here: How to Choose a Battery Isolator for a Camper Van:

If you want to check out that step by step guide, you can do that here: Īlso, we have interactive solar wiring diagrams that are a complete, A to Z solution for teaching you exactly what parts go where, what size wires to use, fuse size recommendations, wire lug sizes, and all kind of other stuff to help save you time and frustration.

If you’ve just stumbled on this article directly without seeing that, there are likely some things we’ve already covered. This is just one part of an overarching “How to Install a DIY Camper Van Electrical System” series. A Battery Isolator combines the ‘house’ battery bank that runs your lights, fans, refrigerator, computers and such to your starting battery so it can be charged by your vehicles alternator.

Battery isolator wiring diagram for rv