Dual Battery Setups! Let's see them! Multiple Batteries Thread!

Amazon description on the ARB 50 qt "0.85 amps/hour average power consumption tested at 37.4˚F cabinet temp. 78.8˚F - 87.8˚F ambient temperature range. Test duration of 66 hours and supply voltage of 12V DC. " No idea how accurate that is, but that would make a group 35 under the hood very doable for my needs. Fridge would be pulling around 15 amps total if i turned the truck off from 4 and didnt start it again till 9 next day. would leave another 15 or so for lights + some charging which is plenty

 

Ran a 2/0 line from the bed dual battery setup to the engine bay stud mount. The way it was previously wired was fine but I’m changing it up a bit and the existing 2awg wasn’t cutting it for the length of run and starting.

 

i made a box to house the battery, charger, etc at the front of my driver side full length drawer system. First time working on something of this scale w/ 12V, this is what i have so far. Running into a bit of a snag as to how to arrange the positive bus bar. The pencil in the below wiring schematic is where i'm not quite sure. I also want to add a master switch in there, does this look correct? If members want to give some feedback that would be much appreciated!

Along with the 40A fused red 6 awg welding wire cable from the starter battery, i was going to run a black 6 awg welding wire cable to the ground point on the frame near the starter battery to the negative bus bar in the box, then ground everything in the box to the bus bar...any issues with that regarding length of run or is there a better way to ground to chasis?

all my wires will be coming in through the same hole on the left side, then through a hole on the front of the driver rear wheel well on down to the frame. I'll also be doing a run to a fuse panel behind the driver's side taillight, and from there circuits up into the super pacific



NOT COMPLETE, WORK IN PROGRESS:

 

To address the wire size question, here is what I typically go off of:


I do have a few questions on your choice of fuses/breakers.

For your master switch, just make sure it can handle the total current you plan on running through it. As for the fuse before it, same deal.

If you plan on running either fuse panels at max capacity at any point in time, those circuit breakers won’t pop because of the 40A fuse you have at the master switch. I would personally lower those breakers to something like 30A. That being said, if you run both panels at max capacity (assuming 30A) then the fuse would pop. Or you could up the fuse before the main switch.

If you plan on using the breakers as switches for the fuse panels, that’s fine. Otherwise I don’t think you really need them.

I may be wrong on some things, so just keep that in mind when other people post up too.

 

Chiming in because I've been messaging with @tacomavan and they asked me to give feedback:

• There really should be no need to run ground from your negative busbar all the way back to the starter battery. Ground it to the chassis somewhere in the back. You'll save money on cabling that way, and there is no difference in functionality.
• I agree with @CttAznRanger about the choices on fuse/breakers and wire sizes. I would suggest several changes:
  • Cables from the Battle Born battery and master switch should be OK at 6 AWG but you might consider moving up to 4 AWG if you find yourself approaching loads near 100A which is the max battery output. Just gives some room for safety.
  • Cable from negative busbar to chassis should be OK at 6 AWG but it wouldn't hurt to bump up to 4 AWG if you are grounding to the back half of the chassis. Running a line all the way back up near the starter battery area isn't really necessary, and if you go that route you probably need to size up which is a waste of money on expensive cable in my opinion.
  • We don't know what your aux fuse panels are rated for, so the choice of 8 AWG and 50 A breakers is something we can't speak on. Just be sure to size this correctly.
  • As mentioned above, if you stay with the 40 A fuse from battery to master switch, you might be blowing that before you trip your 50 A aux fuse panel breakers. Keep in mind the fuses/breakers are there to protect the wire from catching fire. 6 AWG and certainly 4 AWG can handle quite a bit more so there is no harm in increasing this fuse size. Personally I'd upsize to 4 AWG and go with an 80 A fuse, and if you find yourself popping them often you could go up to 100 A (but there is less room for safety at that point since the battery is the limit).

Looking good otherwise! It's exciting once you get that close, and trust when I say once you have the new power you will never go back!

 

Thanks guys, I'll upsize to 4 gauge as recommended and go with an 80A circuit breaker instead of a fuse/master switch combo between house and the bus bar to save on space. My fuse panels are 100A max/30A per circuit so ill be upsizing my cable from 8 to 4 between the bus, 50A breakers, and fuse panels. I have the 50 now so ill leave that in there and if i need to up it to 80 in the future i can do that.

My reasoning for running to the factory ground in the engine bay is that its an existing ground that i know works, but also running 2 cables is typically as easy as running 1, lol. (ive wired my existing and previous homes with cat 6 to every room) It's also out of the way of being exposed to the elements. That would add some weight and cost though. Ill see what i can do closer to the box though on the frame

Updated diagram:

 

That looks a lot better to me.
At least you are running 4 and 8 AWG as max.
I did wiring for Rick a while back doing a dual battery setup, but one in the engine bay one in the trunk. I didn't want to cheap out on it, so I ended up running 2/0 with HMWPE coating. That damn thing was so hard to move around. I believe it was @AllTacosFloat that bought the setup off him, and had a bitch of a time getting it out.

 

Yeah, that sucked!!!

Do yourself a favor and get some welding leads. Right guage and very flexible. I can usually get it between cheap and free.

Welders on the job can only have so many repairs/ taped spots per 100' so I make friends when I see this

 

Just started my dual battery setup.. battery and tray installed now to ground it! Trying to figure out a good spot for that.
Then the red arc isolator is next. Then reworking everything over to the aux battery.. *and no the isolator isn’t going there.. lol

 

some progress, thinking of going up through the bottom of the bed instead of the side. Anyone know the thickness of the bed by chance? Was going over grommet options (https://www.mcmaster.com/products/gaskets/wet-location-snap-in-sealing-grommets/)

also, 175W renogy to help feed the beast

 

I drilled holes in the rear bedside to route my wires. If memory serves, it's maybe 1/4" thick? I had to go to Lowes to get specific grommets because the bed was too thicc for the box o grommets I got from Amazon.

 

Has anyone worked out the "biggest" battery that will fit behind the rear seat of a double cab? Relocating my starting battery back there, so I'd like to go bigger.

 

Do you happen to know if 27f will fit? Got a pair of like to squeeze in there.

 

I don't.
Here looks like group 35: https://www.tacomaworld.com/threads/battery-relocation.571858/#post-21211192
Group 34: https://www.wanderthewest.com/forum/topic/10871-brians-2015-tacoma-and-fleet-build/#entry123905

So if a group 34 fits, then a 27 or 31 should also?

Group 34, 7" wide:
https://www.batteriesplus.com/productdetails/sli34=78agmdp
Group 27, 6.75" wide:
https://www.batteriesplus.com/productdetails/sli27fagmdp?variationCode=VI712717
Group 31, 6.77" wide:
https://www.batteriesplus.com/productdetails/sli31agmdpm



LiPo4: https://diysolarforum.com/threads/battery-behind-seats-in-tacoma-is-this-a-bad-idea.27660/
Found it while searching.

 

thanks

Looks like I'm trying that this week! Still parts shopping for big ass Inline fuse or breaker and a kill switch.

Not sure what tie-downs or tray I'm going with..diy is probably easiest.

 

Should we ask a UT grad?

 

Hah!
UT, Syracuse - either will work.

 

I was looking at this kit but I was just told it's not good for 3rd gen at all. I talked to a company that has installed them. It only mounts to sheet metal and will come loose with off-road use. It will crack the metal and then start banging into surrounding parts. Apparently they are great for Jeeps.

Has anyone installed the second battery on the passenger side? If so where did you put it and did you have to relocate anything?

 

I got a battery tray from Rago that should fit aft of the air intake box. I tried to test fit but it looks like it'll require more than just dropping it in.

 

this is why i decided to go ahead with a full LiPo setup in the bed. No sense buying something that slowly destroys the truck over time