Adding a Second Battery, need suggestions on wiring the ebay

[LittleJohn]

Morning Gents,

First time long time.

I've got a 2018 Expy Max that I'm adding a second battery to. I've got about 30' of nice 1/0 laying around that I plan on using to run a positive to my rear end.

My question is: Do I go through the firewall and run internally, or mount externally along the bottom of hte vehicle? If so, where along the rear body can I reenter the cabin?

I've removed alot of the rear furry and plastic adornment, including the passenger side interior rear quarter panel and I'm finding less room than I had imagined would be available.

I'm assuming this would be a solved problem but I'm having a heck of a time finding any applicable posts anywhere...

Any help would be much appreciated!

lj

 

[stamp11127]

I hope you are going to use a battery isolator otherwise one battery will end up being overcharged.

Engine compartment would be the easiest and require the least cable.

 

[LittleJohn]

Hey Stamp,

The setup is intended to power aux electronics and assorted refrigeration devices off the back of the truck, not necessarily to increase the cars internal ah capacity. As the load will be out the back, the battery, and hence the charger should be in the back (or so I thought?).

As far as my research has indicated, a battery isolator alone wouldn't solve the problem of the "smart" alternator being too smart for our own good and failing to account for a second battery in the mix, never quite charging it to full capacity. I've heard of some people defeating the voltage sensing circuit and going that route but I'd like to keep my voltage sensing wits bits.

I've got one of these guys ready to drop in: https://redarcelectronics.com/products/dual-input-40a-in-vehicle-dc-battery-charger

With it, voltage drop to the battery becomes a non-issue, but I still don't know if it permanently isolates the car from the aux battery, or if I can switch them over if I want to run the radio off aux power.

As far as 2 batteries in the engine bay. is there any specific spot you're thinking of?

 

[OrangeWhipX3]

Seeing as you live in a salt state I'd do everything I could to not run that cable on the exterior. That's about all I can offer you for advice

 

[stamp11127]

According to the manual it does isolate the two batteries - see page 4 of the manual. I'd be inclined to go with the lithium ion battery if cost isn't a factor.

 

[Plati]

Not an Expy but ... saw this 4Runner at Bowman in Glacier few weeks ago. Extra battery mounted by firewall in engine. Other electronics in engine bay. Solar collector can be on roof or ground by cable. ARB freezer/fridge on slider rails in back. Looks like it works great!

 

[Artie]

I just ran cable 6 gauge cable (this stuff: https://powerwerx.com/welding-cable-epdm) from my battery to my hitch for our overland trailer and I ran it underneath the vehicle on the passenger side. I used some split loom and taped the loom every foot or so. I ran the passenger side because that’s where my battery is but, unfortunately, so is the exhaust. It was easy enough to avoid the exhaust until the rear wheel and even there it wasn’t too bad. As for entry in the rear I’d have to think punching through where the jack is stored would be the easiest place. That way you could store the cable in there hidden when not in use. It was fairly easy to run and there is a lot of space along the frame with plenty of areas for zip ties. You can find lots of options for more robust loom or shielding if you are concerned about damage.

 

[LittleJohn]

Hey Guys, I figured resurrecting this thread would be appropriate. I actually ran 4 gauge internally to the rear along with 2 runs of cat 5. I've installed a redarc battery gauge on the driver's side A pillar and got myself a battleborn lifep04 to hold the juice.

Here's where I complicated my life: I took my spare tire out and mounted it externally off my hitch to make room the inverter, charger, and batteries.

Is my only option to go full custom on the spare-tire shaped underbody storage?

 

[Hurricane]

Littlejohn, from where to where did you route your cables? I have an Exeltech SI 2000 watt inverter on the way. I intend to make an overland / daily driver with ours.

 

[Fozzy]

Guy on Instagram put two Odyssey’s under the hood of his Gen4.



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