Choosing the correct AMP for Battery Isolator

[fiddypal]

I am looking at these "Stinger Battery Relay Isolator and Relay" on amazon so i can install a second battery in my truck to use as a house battery.

They come in all different amp ratings, 80amp, 200amp, 500amp.....


What amp rating should i get?

Thanks!

 

[Scrapdaddy]

I believe its according what your alternator is putting out. Here's the one I used. They are very helpful in picking the right system. http://www.perfectswitch.com/isolators/

 

[fiddypal]

Ok so with that said.... should i worry about putting a beefier alternator in? My truck already has an empty bay for a 2nd battery under the hood so i am guessing it might already have a good enough alternator in there?

Thanks!

 

[Scrapdaddy]

No, don't worry. I put a 250 amp alt. in my FJ55. It has a 5.3 Chevy in it, but the alt. makes a true 180 amps. at idle. Two battery system.