Battery Isolator Or Separator

ocean4200 · August 18, 2009

Hello,

I want to install another battery in my truck. The alternator can goes up to 145A. The main battery is a AC DELCO 70A/h. I will buy the same model/brand for the auxiliary battery.

I would like to know if someone aleady installed an isolator OR a separator (I don't know which one to choose since I don't know if the alternator is internal or external sensing).

Also, what brand to choose?

By the way, I know people install their batteries in parallel but I don't think this is safe...... for many reasons.

Thank you

2COR517 · August 18, 2009

Batteries wired in parallel are no more unsafe than single batteries. Parallel batteries are used in all big rigs, buses, most diesels, golf carts, home solar power storage, you name it. If you want two separate batteries, just use a snow plow pump relay. Wire it to energize when the key is on.

ocean4200 · August 19, 2009

I see what you are saying.. it is just that an isolator can act multiple way like a relay or really isolate current between both battery. The relay you are speaking need a sensor to detect current presence from the alternator. Then it links both battery... Is it that?

2COR517 · August 19, 2009

The alternator is internally regulated, so you don't have to worry about that. The problem with "cheap" isolators is they tend to lose up to a volt to each side, and generate significant heat. The do however prevent one side/battery from pulling current from the other.

Someone makes a really nice isolator that has internal switching so there is no voltage loss when charging, and complete isolation too. But I think they are more than $400. What loads are you trying to separate?

ocean4200 · August 19, 2009

each battery is 70A/h. I will install an audio AMP and a CB probably on the secondary battery. That's all. The amp could be 600W max.

Do I need an isolator at least the AMP as the alternator?

Pilot12 · August 19, 2009

each battery is 70A/h. I will install an audio AMP and a CB probably on the secondary battery. That's all. The amp could be 600W max.

Do I need an isolator at least the AMP as the alternator?

I found Hell Roaring to be a good site and they have a good rep. Mike there is very helpful and answers emails. They might have what you need.

http://4wheeldrive.about.com/gi/dynamic/of...om%2F4wheel.htm

2COR517 · August 20, 2009

Keep it simple. Just use a snow plow pump relay. Cheap, effective, no voltage drop. Only need a #10 charge wire for your setup. You can use the CB and/or stereo till the aux battery is flat and the truck will start right up. Or, if you're like me, you can leave your headlights on overnight, and jump start yourself.

ocean4200 · August 20, 2009

I know a simple relay can do the job... and isolators seems to be tricky about alternator type... I think I'll go with a separator. In fact, this is the same as a relay but it is smart! SurePower sells them.

What I don't like with Hell Roaring is that the isolator doesn't meet the alternator AMP. I asked them why and couldn't get precision to this answer. The guy wasn't sure so... I try to avoid thing that aren't sure. I know they sell good products. It just doesn't do what I want.

I'll go with a SurePower 1315-200.

Anyway, if you guys think something different, let me know! I'm still looking at possibilities!