I was thinking of mounting a group 24 or 27 AGM deep cycle Somewhere under my forerunner. It’s lifted, I could fabricate a bracket for it, with my ARB compressor I just don’t have any room under the hood. Has anyone ever done this or seen it done? The reason is I just bought a small refrigerator and I wanted to have a back up battery to run it when the car is off

I can't really speak to putting a battery under the truck, but I do know several companies have made dual battery trays for different spots in the engine bay, have you already filled the spaces on the passenger side? There are trays that allow you to put a battery in the front or back of the passenger side engine bay.

I am going with the c4 fabrication tray for my dual battery system and I have my arb compressor on a slee tray on the drivers side. Before I decided on going this route I just used a small lithium battery pack to keep my fridge working when I turned the truck off. I had the battery pack charging from a factory cigarette lighter port and had the fridge plugged into the battery.

Another option that may be more versatile but less convenient perhaps is running the fridge off something like a GoalZero or Jackery battery pack. No need to mount it and you can take it around with you wherever you need the power too. They aren’t cheap though.


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Don't do it. Even if you think you can secure it well it may become an issue in case of accident. Also exposure to elements is unavoidable there.

Sounds like a great way to need a new battery every year.

Not an ideal location from an elements exposure angle. If I could do my second battery project again I would mount a Lithium Ion battery in the rear of the vehicle. Plenty of space back there.

Not sure where you'll find room - but battery mounting to frame rails is pretty common for hot rods. You can just buy frame mounts from a variety of vendors.



I think the Sportsmobile vans had them mounted down on the frame rail OEM.

That said - I've never needed a second battery. My fridge will run off my regular battery for around 4 days without a recharge. With a 100w solar panel - it's really never an issue. And I guess I haven't used my winch enough for long enough in a row to kill the battery like I do on my FJ40 because I just don't use the 4Runner in a way that I'd do 5 or 10 back to back full length winch pulls.

I'd suggest just buying a lithium jumper pack in case you do take the car battery down too low and use the regular battery. It's worked pretty good for me for 6 years.

Given the availability of Lithium Iron batteries at reasonable cost, I concluded that if the goal is to power fridge/electronics/lights/etc. it's MASSIVELY simpler just to get a Dometic PLB40 battery. (Note, that's for me - not looking to start a debate.) The thing is very well designed, simple, has a built-in charge controller, and really does everything needed.

I went with the Dometic because it's Lithium Iron not Lithium Ion, which means ~double the battery life & a discharge rate that doesn't decay as it ages. I believe Goal Zero etc. use Lithium Ion, so if you are planning a lot of use, compare.

The other thing I bought is a 130W Bugout solar blanket. Because the Dometic has a built-in charge controller, it's simple. Plug it in and put the blanket in the sun and infinite energy. Done.

I have a wood platform in the back of the 4Runner, and am currently adapting it so there is a spot for the battery out of the way behind the fridge.

I thought about putting in a 2nd battery and wiring at the start, but the simplicity and reliability of this system won out.

i do have a lithium jumper pack,, i've found that getting a good brand is key with those. the costco ones are fairly worthless for starting a car or even staying charged