So I decided that I needed a 2nd battery to fill up the extra battery tray under the hood of my truck. I got the parts together and got it done this week.

2 batteries are better than 1


battery isolator


150amp circuit breaker


Now you may ask why I wanted 2 batteries. Well I am putting in my CB, 500 watt linear, and ,lights in my dog box. I am ordering a 12,000 lb winch for it in the next couple of weeks with 2 285,000 candle power KC off road lights. I didn't want to be running all the accessories off of just 1 main cranking battery. The isolator I got has a override that will jump the main battery off the Aux. battery if the cranking battery happens to go dead. The main cranking battery is like 650 Cold Cranking AMPs and my AUX battery is 850CCA.

 

so are the current batteries hooked up in parallel or just completely seperate and the isolator charges one at a time?

 

They are completely separate. The isolator is hooked up to the main battery and monitors the voltage on both. When the Aux battery is low and there is more than 12.8V on the main battery it turns on the charging circuit. When the charging circuit is on it charges the Aux and Main battery from the alt. There is a override button on the isolator that lets you jump start the vehicle from the Aux battery if the main battery happens to become weak or dies.

 

When the engine is running your alternator will be powering your accessories, not your battery, unless your alternator output is insufficient.

Have you upgraded your alternator?

peace
Hog

 

Alternator does not run accessories when the engine is off. Now I am draining my Aux battery and not killing my main battery. All my extra stuff- CB, 500 watt linear, off road lights, 12,000 winch, dog box lights will be run off aux battery. More insurance that I don't kill main battery. The alt is the upgraded unit from GM

 

fair enough, sounds like a great setup!
I was just curious about the parallel or seperate thing cause when you start dealing with 2 different rated batteries and age you can come across charging issues and prematurely burn out the alternator but sounds like you got it figured out!
you mentioned a GM high output one, which one did you get? I may need to look into one for when I start playing with car audio again

 

The isolator keeps them separate. It charges the AUX battery just like it would run the headlights. Or that's what I get out of the directions they sent me. I have been researching this setup for awhile. I found out today that my truck has the 140amp version ALT on it I may need to upgrade it but I am going to run it until it for some time and see how it does.

 

Pretty slick...nice work. I'm gonna duplicate your setup.

 

I'd be interested in seeing the cost on having the current alt in the truck re wound for more output, cause I havent found any after market ones under $300!

 

Its not to bad

1000CA battery $86
150AMP isolator $79
150AMP circuit breaker $31
battery wire different lengths $40
Total $236