Battery Isolator Question

[rogue909]

So I am installing a deep cycle battery in my 2005 suburban and I'm trying to figure out how to separate it from the starting battery to prevent them from depleting themselves when the vehicle is off (also, I want to use the deep cycle to run things when the truck is off.)

From my understanding, diode based isolators will prevent the batteries from depleting each other but have a voltage drop. This voltage drop stops the batteries from getting a full charge and is a no-no.

They have solenoid based isolators, these combine the batteries in parallel when the vehicle is on but separate them when it is off; they can also be designed as voltage regulated isolators that isolate when starting battery is below a threshold. When operating a deep cycle battery with the vehicle off it can decrease the voltage across the battery (duh) but when the solenoid turns on a surge of power will run from the starting battery to the deep cycle. This can short the batteries and fry electronics (this is also a no-no).

I have seen some solidstate isolators but the ones I have seen have been in excess of $400, this seems like quite a lot considering what I am getting out of it.

What have you guys done for battery isolation and where did you get them?

 

[AFBronco235]

I went with Painless Wiring's solenoid setup. I admit, I'm not using a deep cycle battery for my second, but I don't think there would be a problem. The kit I used is set up so that I can use the second battery with the first or separately. I do need to hook up a voltmeter for the second battery though. It cost around $130.

Stay away from isolators. Those will drain your battery and won't allow for a proper charge and are best used for sound systems rather than accessories like what you'll be using.

 

[Shocker]

Post the question in the 12v section. You will get more responses.

 

[crawler#976]

http://www.amazon.com/Blue-Sea-Syst...qid=1401216390&sr=8-1&keywords=blue+seas+9004

I use the switch above and keep the batteries hooked up in parallel unless I want to isolate the fridge battery. This has been the common way to do it in marine applications for years - works there, works for me. Nothin' fancy, just on or off.

 

[evldave]

A long read, but lots of good information in this thread...

http://www.expeditionportal.com/for...ke-a-cheap-isolated-dual-battery-setup-for-50