FJ Cruisers of Northern California

Dual Battery setup Kits

Just installed a winch and want to add some spot n flood lights and such. I think I need a dual battery to be safe. Not sure where to start or which one to get. Are dual batteries common in our rigs? Are they difficult to install? Which kit are you guys running? Thank you for your help and comments. :)

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Permalink Reply by Steve Hope on April 2, 2014 at 10:48am

Easy, you just need physical space and custom length cables available at trailer supply and auto supply stores and an isolator rated for expected current draw ( usually 150A and cost +/- $75 )

Primary battery and secondary battery are connected to the isolator so the alternator charges both. In regular mode, primary battery provides power but when engine is off, secondary battery runs what you wire it to. The primary battery is not drained in this use because the isolator is a pair of back-to-back rectifiers in an aluminum heat-sink that allows current flow in one direction only. So you always have primary battery power to start and run the vehicle even if the secondary battery is drained.

Check with our guru Nestah, he did a great job on his FJ.

Steve Hope.

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Permalink Reply by Steve Hope on April 2, 2014 at 11:09am

I would also say that a dual battery set-up maybe unnecessary as long as you keep the engine running ( thus the alternator) while using the winch.

If you want to use your lights extensively and other electrical components, with the engine off, then a dual battery set-up would be of good value.

Steve Hope.

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Permalink Reply by Sonof40 on April 2, 2014 at 11:09am

You can save money by researching and gathering all the necessary parts and building your own system like I did. Or you can pay about $100 beyond the cost of parts to get a complete system including pretty good instructions and excellent customer service by buying this:

http://www.dirtyparts.com/store/detail.cfm/DUAL-BATTERY-KIT-FJ-CRUI...

Which I would do if I were doing to today.