Cool. I'm curious what it cost you.

I'm not sure exactly what you're wanting to do. 30amp capacity isn't very much for connecting two batteries (I'm assuming one use would be if your starting battery is drained and you need to jump it with the winch battery, or vice versa).
I'd use a 200 amp continuous duty solenoid, like a Cole Hersee

Cole Hersee - 200a continuous duty
PN 24143 - Silver contacts
replaced by
PN 24213 - Silver Tungsten Contacts
Solenoid continuous 4pole 12v carbide, 24213, Cole Hersee - Ryder Fleet Products



http://www.colehersee.com/assets/fil...5Solenoids.pdf

 

Actually, come to think of it, why do you want the relay closed when the engine is running? That's when the alternator would be charging both batteries.

 

Won't it still be charging through the isolator when runnning?

 

I paid 24.00on Ebay for the Isolator....

 

hummm...
Car running.....solenoid not activated......isolator determining which battery to charge....2 battery system not in parellel..."isolated" from one another

car running.....solenoid not active....isolator determining which battery to charge...main battery bad....attempt restart...fail...activate solenoid...batteries now in parallel...car start ...pass

car running....solenoid not active....isolator determining which battery to charge....2 battery system not in parallel...activate winch....load only on main battery....activate solenoid...2 battery system in parallel....activate winch....load on main and aux in parallel.

There are someother senario's but, that conveys the point....I think...

 

Yes, that's why I don't know why you want the relay closed with the engine running, it serves no purpose that I can see.

Ok, yeah, then you definitely don't want a 30amp relay in there.
$24 is a damn good price for a 160amp Sure Power Schottky diode Isolator. I assume it's used. Be sure to test it as soon as you get it. I bought a used one off ebay years ago and didn't do that. 6 months or a year later when i went to hook it up, it was not working on one of the posts.

 

It's going in as soon as I get it already have the the pre wiring done so I will test it that day....keeping fingers crossed...

 

Sounds good, just be sure to not leave feedback until you've tested it. Once you do you can't open an ebay defect.

 

Bring a fire extinguisher just in case

 

That would be funny if it wasnt so possible with me!

I just received the isolator in the mail...brand new in the box...unopened! Not sure why but I'll take it...