Dual Battery Setup : LiFePO4 vs AGM vs Deep Cycle, Lead Acid, etc

Octanejunkie

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Planning my next battery replacement, maybe go dual bat. It would appear 2 LiFePO4s could fit where the factory battery is now, or in the cargo area.

Any thoughts about best battery tech for wheeling?

Also, what gauge wire for a rear/cargo mounted battery with an 80 amp alternator? 2 AWG?

EDIT: decision made here
 
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Stairgod

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Planning my next battery replacement, maybe go dual bat. It would appear 2 LiFePO4s could fit where the factory battery is now, or in the cargo area.

Any thoughts about best battery tech for wheeling?

Also, what gauge wire for a rear/cargo mounted battery with an 80 amp alternator? 2 AWG?
Hell no on the LiPos unless you are knowledgeable enough and willing to be able to tweak your ECU to up your voltage output on the alternator to keep them happy. They do not tolerate the lower charging voltage that standard alternators put out
Wire size for the battery relocate is determined by length of cable run and the max load, NOT amperage of alternator.
If you have a front mounted winch then it will be your diggest draw. If not then your starter is.
00 would be my recommendation.
 

Arcticelf

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Hell no on LiPo unless you like fire. In which case just throw a burning road flare in the back seat and hold your phone sideways. Eventually LiPo or it's descendants will replace lead-acid, but we're not there yet, and LiPo fires are practically impossible to put out without a firetruck full of the right foaming agents.

The simple answer is an Optima Yellow top (deep cycle, starting rated) with a blue-sea Automatic Charging Relay to isolate the house batter from the starting battery. A dedicated starting battery with a dedicated deep cycle (I forget the optima colors) is better, but you can't use a true deep cycle battery for running a starter more than a few times before killing the battery.

Whatever technology you pick, move them out the engine bay and make sure to get sealed batteries so you don't poison yourself.

00 high strand count welding cable is probably good for any location on the truck, it's flexible and the higher strand count lowers the internal resistance of the wire, which reduces heat. Conductivity, the inverse of resistance, is based on the total surface area of the wire available to transmit electrons, so more, finer, strands have more surface area per total wire diameter.

Last time I looked (which was pre-covid) Amazon had the best prices on all the stuff you'll need to do a battery relocation and "big 3" wiring upgrade in the engine bay.
 
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Optima battery's have become trash over the yrs and I only run one when its free from a salvaged vehicle. Something to think about with the wet cell lead acid when wheeling is the extreme angles u'll be at and the battery acid can come out. Another thing to think about with LiFePO4 is lithium battery's don't like cold temps or the temp dips in the desert at night, I've had to explain a few times while out exploring and rock climbing to people in there "van life" units this when no of their electric shit works 1st thing in the morning, I tend to agree that this tech isn't where it needs to be yet to run in are type of application but there are ways which involve voltage controls etc... for now a good AGM seems best. I mounted my home batteries to my tire swing out.

Are u wanting more Battery reserve for more of an "overland" type build or just because...
 

4runner DOA

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i only killed one, in 18 months of use, but it died quickly.

Yeah the first two were dead at about 15 months. Not sure when the last one died because the rig sat for 6 months. Couple months ago there wasn't even enough power to unlock the doors. The Northstar I got is bigger and heavier but it has a better reserve AH for sitting around. I should really stick a solar trickle charger on it.
 

Octanejunkie

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Great input so far, gentleman. Appreciate it.

00 seems to be the consensus for remote battery cabling. What about running dual batteries one in the back and one up front? It's really not a requirement, just over-building.

The appeal of a cargo/rear-mounted battery includes shifting weight to the rear where I've got taller springs and using the stock battery location for my OBA ARB compressor.

How about Odyssey, like ODX-AGM24F or a Group 35?

Battery to winch cabling 1/0 AWG?
 
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I've have a Northstar 27F AGM in my turd gen DD for three years. First two of that, I was running it at stock voltage, so it was being under charged on daily basis. Would hook it up to a charger from time to time, but still. Not only running it at lower voltage, but also using it as cranking battery, which they might not like all that much....
If you opt for a nice, sealed, high reserve AGM, you might want to look into raising your alternator's voltage
 

Octanejunkie

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I've have a Northstar 27F AGM in my turd gen DD for three years. First two of that, I was running it at stock voltage, so it was being under charged on daily basis. Would hook it up to a charger from time to time, but still. Not only running it at lower voltage, but also using it as cranking battery, which they might not like all that much....
If you opt for a nice, sealed, high reserve AGM, you might want to look into raising your alternator's voltage
Cadillac alternator is up for consideration...
 
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Cadillac alternator is up for consideration...
OK, cool.
Also look into voltage Booster. I know there is "Mike Singer Voltage Booster" that is being used in 2nd gen Tacoma crowd (it does not work in 3rd gen Tacos), but I'm not sure about t4r
 

Arcticelf

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Move the OBA to the back with both batteries?

Getting the stock battery out from under the hood will help save your fender/rad core from cracking, and free up space for bigger tires.
 

4runner DOA

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I've have a Northstar 27F AGM in my turd gen DD for three years. First two of that, I was running it at stock voltage, so it was being under charged on daily basis. Would hook it up to a charger from time to time, but still. Not only running it at lower voltage, but also using it as cranking battery, which they might not like all that much....
If you opt for a nice, sealed, high reserve AGM, you might want to look into raising your alternator's voltage

I've been running a 240a alt for like 4 or 5 years.
 
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Octanejunkie

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Move the OBA to the back with both batteries?

Getting the stock battery out from under the hood will help save your fender/rad core from cracking, and free up space for bigger tires.
I was thinking about putting a second fuse/relay box and OBA where the stock battery is to reduce access to the rear hatch
 

4runner DOA

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Out of curiosity, what kind of charging voltage is that pushing? (at the battery)

When it was brand new I was pushing 14+ now it tends to stick around 13.6-13.8. probably wouldn't hurt to pull it out and clean some of the dirt and dust out of the coils.
 

Arcticelf

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I was thinking about putting a second fuse/relay box and OBA where the stock battery is to reduce access to the rear hatch
I killed a ARB compressor with water under the hood and again under the rear fender. If I ever do another one it'll be in the cab with a bulkhead connector under the hood.

Putting a fuse/relay box where the batter was makes a great upgrade though
 

4runner DOA

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I killed a ARB compressor with water under the hood and again under the rear fender. If I ever do another one it'll be in the cab with a bulkhead connector under the hood.

Putting a fuse/relay box where the batter was makes a great upgrade though

How'd you kill them? They're pretty well sealed unless you sucked water into the intake past the filter. I got a twin that wasn't working well. Cleaned it up and swapped the relays and it fired right up.
 

Arcticelf

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How'd you kill them? They're pretty well sealed unless you sucked water into the intake past the filter. I got a twin that wasn't working well. Cleaned it up and swapped the relays and it fired right up.
The relays aren't sealed at all, and when they short due to water exposer the compressor kicks on and sucks water past the filters. New relays and cleaning it up mostly fixed it, but output was never the same. I think there was some corrosion or damage to the seals.
 
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