Dual Battery Set Up Help

[LS1FJ40]

Ok. I'm under a time constraint. I need to get my dual battery system working tonight because I'm going to be out of town over the weekend and need my fridge/freezer to keep food cold. I've been running the fridge off of the house battery all day then charging it at home at night. This is and a pain. Plus I won't be able to do that over the weekend.

Here is what I have. I want to make sure I have everything so my house battery can charge off the alternator and so I don't start a fire.

(1) Starting Battery - Interstate Batteries MTP27 810CCA
(1) House Battery - Interstate Batteries 27MXHD Deep Cycle
(1) Blue Sea SI-ACR Automatic Charging Relay
(10') 2ga Welding Wire (red)
(10') 2ga Welding Wire (black)
A bunch of heat shrink and connections (the hammer on crimp kind).

What is the easiest way for me to set this up? I don't have a ton of time tonight so appreciate your help.

My limited electrical knowledge tells me I need a 150amp fuse at each positive terminal for the batteries. And to upgrade the ground from the negative to the engine block to the 2ga to match the other. Is this correct?

And does anyone have the skills to spell it out in a neat diagram? When I have more time I will add a battery switch and my solar panel but don't have the time right now, unfortunately.

Thank you al for your help!

 

[LS1FJ40]

I have the fridge wired directly to the house battery with Joey's Wits' End Anderson Pole quick disconnect wiring harness.

I will also connect all of my lights to the house battery down the road as well.

 

[dales33]

revolution dual battery kit instructions - Google Search.

I earted mine to the frame though and added a 100 amp breaker

 

[greentruck]

Do you have another tray in the engine compartment already? If not, 10' of cable is going to leave the battery in the front floorboards somewhere...?

See the other ongoing discussion for the issues. If you can secure the battery in the engine compartment somewhere, then cable over to it taking care to insulate and rub-proof it as you go and put it in parallel with you main. Unless you fridge is crazy inefficient, that should hold you overnight and start in the morning.

For a weekend, I wouldn't foresee any major issues, but for longer term, you do want the batteries to charge independently.

 

[LS1FJ40]

Yes. I already have the battery tray installed and the PAIR system disabled.

I was told that running them in parallel is a bad idea since my house battery is a marine (deep cycle) battery.

 

[LS1FJ40]

 

[greentruck]

I'm not sure that there's much difference by battery type. Even if the same type, running in parallel is bad long term. One battery will always be charged inadequately. For a weekend, I don't believe that's much of an issue, but maybe someone else can chime in who knows more specific info.

 

[dales33]

Id still go with a VSR.
They should be cheap in the states like everything else compared to AU and you can pick up a basic unit for under 40 here.
It ensures your cranking battery is always priority charging but automaticly charges the second.
Its a no fuss set and forget system that keeps your batteries well maintained

 

[JeepinPete]

If you are in a rush, wire them parallel for the weekend, update when you have more time. The only possible negative is you will be drawing from both batteries while the fridge is in use unless you disconnect the house battery once you arrive at your destination.

 

[LS1FJ40]

Isn't the Blue Sea SI-ACR essentially the isolator so that the cranking battery doesn't get drained down? So you run the batteries in parallel but have that in between so that the two are separated as far as draw but will both charge?

 

[dales33]

Im not familiar with that product but if you google Revolution dual battery system that is the type i have and anything similar will work just as well

 

[Dirty Koala]

Here is the wiring schematic for your isolator. That unit is auto sensing and will connect when the primary battery reaches 13.6 volts, and disconnect when voltage drops below 12.75 volts.

Run a cable from each side of the unit to each of the positive terminals and run the ground wire from unit to primary negative and you should be good to go.

 

[LS1FJ40]

Here is the wiring schematic for your isolator. That unit is auto sensing and will connect when the primary battery reaches 13.6 volts, and disconnect when voltage drops below 12.75 volts.

Run a cable from each side of the unit to each of the positive terminals and run the ground wire from unit to primary negative and you should be good to go.
View attachment 1272939

Thanks! I was just going to show the diagram that came with it and what I drew on it. I'll post it in the next comment.

 

[LS1FJ40]

 

[Dirty Koala]

Only change I would make it to run both batteries negatives to the block, rather than to each other.

 

[Razorbackcruiser]

I understand the desire for dual batteries but I wouldn't worry too much if it's just for a weekend (unless you're not planning on moving the truck at all). I just got back from an 8 day trip to Colorado. I run my Indel B off of one Diehard Platinum (the smaller one at that) and had no problems whatsoever. I set my "shutoff" switch on the fridge on medium and let it t ride.

I will say I have an antigravity battery under the front seat just incase but I wouldn't think you'd drain one battery over one weekend.

 

[TomH]

This should work.

 

[Dirty Koala]

As long as you also run a ground from isolator to negative battery terminal, then I agree.

 

[TomH]

As long as you also run a ground from isolator to negative battery terminal, then I agree.

Right. I thought that ground was part of the start isolation system but the ACR needs to be grounded too.

 

[LS1FJ40]

It works!

House battery

Cranking battery

And don't judge the washers. I ordered 4x5/16" terminal ends but they shipped 4x3/8". They were a little loose so I added a washer to hold them tight.

Also had to make due with the cheapo negative terminal on the cranking post. I had this one laying around. I have OEM positive terminals I'm going to use but didn't have enough 2ga cable to make a new ground. Will order more welding cable and do it proper.

Thanks for all of your help guys.