Dual Batteries setup?

ntsqd

Heretic Car Camper
Eleventeen.


Seriously though, more info is needed. What are you powering back there and what do you expect that you might want to power back there in the future?
 

Beowulf

Expedition Leader
Even though it is absolute overkill I would use 2 guage welding cable with wire looms if I was going to be mounting a power distribution block in the back of my vehicle.

Necessary? NO. Fun? Yes. Good luck in your project.
 

lexwoody

Adventurer
Eleventeen.


Seriously though, more info is needed. What are you powering back there and what do you expect that you might want to power back there in the future?

For now two 12v outlets. Later a 800w inverter. 4 guage is what a need.
 

alia176

Explorer
Even though it is absolute overkill I would use 2 guage welding cable with wire looms if I was going to be mounting a power distribution block in the back of my vehicle.

Necessary? NO. Fun? Yes. Good luck in your project.

When you run a 2 gauge wire, what size fuse/breaker do you use for it? Just curious.
 

Beowulf

Expedition Leader
This was much more of a Hypothetical. I have 2 gauge sitting around so that is what I'd use. Plus, then if I wanted to run a winch off the back I'd already have the cable run.

Also, this would give you tons of capacity to run your fridge (or a several fridges) work lights, RTT Lights,....etc.
 

alia176

Explorer
This was much more of a Hypothetical. I have 2 gauge sitting around so that is what I'd use. Plus, then if I wanted to run a winch off the back I'd already have the cable run.

Also, this would give you tons of capacity to run your fridge (or a several fridges) work lights, RTT Lights,....etc.

Soooo, what fuse would you use for 2 gauge? :coffeedrink:
 

Beowulf

Expedition Leader
Sorry about that. I really had not put much thought around which fuse box to use, but I would probably use one like this.

http://bluesea.com/category/5/21/productline/126

126.png


I hope that answers your question. As I had no plans to actually do this I had not done much research.

I don't really have anything back there. I'm sure there is some electrical engineering need somewhere, but I'm just throwing out generals.

Depending on your application you could mount the fuse box like this one under your hood. Figure out your exact power needs for each item and run one size larger to each one.

But I'd still run 2g to the this little box. Maybe it would blow something up :Wow1:, but I'd give it a go. :smiley_drive:
 

BigJim

Observer
2 ga wire

will require a substancially larger fuse than the picture in your post. That panel looks great for appliances like lights and such but hardly appropriate for a big inverter or a winch. My winch can draw up to 400 amps.

The correct way to do this would be to install the 2 ga fuse at the battery. This will prevent a fire and other bad things in the event the 2 ga wire is nicked or shorted to ground.

This has happened to me and I was fortunate in that I had a hatchet available to chop the wire as it began to burn and my battery began to smolder.

David Levy Company sells all sorts of cool high current DC stuff.

Happy high current
 

Beowulf

Expedition Leader
Yes, this would be the block I'd use for the all appliances and lights. If I was running a rear winch I would actually completely by passe the fuse block.
 

alia176

Explorer
Hee hee, looks like BigJim beat me to it! I was trying to corner you into telling me what size fuse/breaker you'd use for the 2gauge wire. My point, in a round about way, was to make people understand that running a huge gauge wire needs to be protected with a proper size power disconnecting device (manually reset or auto reset breaker, slow blow fuse, quick blow fuse, etc)

So, using a 2 Gauge wire to feed your appliances (using the link posted above http://www.wranglernw.com/download/fullcatalog.pdf), we see the following:

a 2 Gauge wire can carry 140 amps of power up to 15'

So now, you gotta ask yourself, will you really need 140 amps at the back of your rig? You might, I don't know your application but this is the size of fuse/breaker you need to install at the battery before energizing your #2 gauge wire.

If anyone is planning on running a high quality inverter for 120vac power in the back of their rig, they should run the pos and neg power cables straight to the battery. Unless you're using quality lugs and terminals, hot spots created from wire junctions can be somewhat unsafe and RF noise interference may get created.

I know most of you already know this but ......:)

Cheers.
 

Beowulf

Expedition Leader
I feel bad we kind of hijacked Lex's thread. Plus, I glossed right over the inverter part. At 800W you would definitely need something more substantial than the Blue Sea unit I posted.

Lexwood,

What is the max amp draw of the inverter you are wanting to use?
 

lexwoody

Adventurer
Some threads post say to run a 2ga wire for furture purpose and a 150 amp fuse breaker at the aux battery, 75 amp fuse for the 800watt inverter and 75 amp breaker at the fuse panel. If I ran more that requires more amp drawn. Update the fuse or breaker at the aux battery. Right? A lot of this is just pre-wiring.

Steps
1. Aux Battery and engine area mounting.
2. 2ga. wire to rear fuse panel. (rear)
3. 2 12v outlets. (rear)

Or

Run two 10ga. wires for the 2 12v outlets and call it that for a while.
 
Last edited:

dustboy

Explorer
What would be the minimum gauge to allow the (rear mounted) aux battery to be used for emergency starting?
 

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