dual battery setup confusion

[maddogrc]

hey all,

i'm starting to do more camping/4wding now since i have a PROPER 4wd, none of that 2wd non-sense haha.

my main concern is that with the whole wiring setup, i understand it as that when the car is turned off the auxilary battery is LIVE and powering items.

however, if the main battery is isolated, doesnt that mean all the car lights and cig lighters, etc wont work since the only power allowed to be used is from the auxilary battery, yet the main power cable to power all the car things is on the main battery?

like, if i plug my engel into the cars standard 12v socket, and the car is off, wouldnt the main battery be isolated and thus the engel not get any power as the aux battery is activated?

i'm sure i'm thinking over my head here, but the way i see it is that i have to rewire all my plugs and sockets to the auxilary battery to use my fridge and lights when the car is off as only then is the aux battery active.

if anyone has a good diagram or pics of there setup showing CLEARLY how its setup, or if anyone wants to explain how i can still use all my 12v sockets without rewiring it all to the aux battery then that'll be awesome too!

cheers,
george

 

[Old.Tony]

If you're using a standard isolator (Redarc, Projecta) then here's what you have:

* Car Battery connecting to car's normal system and SOMETIMES isolator

* Isolator connecting to aux battery

The isolator manages the decisions about whether the car battery is connected to the isolator or not. The isolator CAN be told to pass power back in order to assist in a vehicle start - hopefully not something that you need too often and only ought to need it if you wire things up wrong.

The aux battery is the guy that EVERYTHING is supposed to connect to when you're stopped. The normal power outlets in the cabin are part of the car's normal system, so when you're stopped and the ignition is off, these should be off. The aux battery should run a separate system altogether.

This allows you to camp and enjoy your time while still having a main battery to get the vehicle going again. Feeding power from the aux battery into the main while you're camping will, unfortunately, also consume power from the main battery - once two batteries are joined together in parallel, they will try to equalise with each other. The battery with the higher voltage will try to charge the other and in the end, you have two flat batteries.

So the wiring diagram ought to be very simple:

main battery -> big fuse -> heavy cable -> isolator -> heavy cable -> aux battery -> fuses -> aux outlets

The isolator may not require that fuse - check the documentation. Other than that, it's a straight line to the end and those outlets are independent of the vehicle, so that the vehicle is never compromised.

 

[Matt76]

Put very simply mate, when your car came out of the factory everything ran off your main and only battery, when you put an auxiliary batt in, only the items that you decide to hook up to that battery will run off it, and even though the batteries may be isolated, you headlights, interior light etc will still run off you main battery and still work when the car is off. All that is isolated is the bridge between the 2 batteries.

 

[mgladwin]

You have got the general idea of the isolator correct George.

If you want to run things off your aux battery then you will need to re-wire everything to it that needs to be on when the car is off. Say you have the Engel in the back of the Cruiser then just run a dedicated power feed to the fridge from the aux battery. Other accessories you will just have to wire up accordingly.

There is no easy way to hook up all your existing 12v sockets in the cab to the new aux battery (as Tony stated it is a separate system) but it is possible if you rewire each one individually. Pain the in #$% though....

Tony explained it well, the main battery and everything it is connected to (basically everything) is its own system. Then once you have an isolator and aux battery in the mix you have another separate system to run all your accessories off. It only becomes one system when the isolator is in contact and the alternator is charging both batteries.

Hope that helps.
Martin

 

[lapsed]

Hey George,

If you need a hand or would like to see a setup let me know. As I have mine don in my Nav. Here is the instructions for the redarc solenoid that i used

Chris

 

[nathan96]

Just to correct old.tony sequence

you need a fuse as close as possible to the positive terminal of BOTH batteries not just the aux battery.

 

[KraftyPg]

Just to correct old.tony sequence

you need a fuse as close as possible to the positive terminal of BOTH batteries not just the aux battery.

Isn't that what he said?

main battery -> big fuse -> heavy cable -> isolator -> heavy cable -> aux battery -> fuses -> aux outlets

 

[roundy]

So id be rewiring the stereo and adding more cig sockets, u just wont be able to use ur HID spotlights as camp lighting george

 

[nathan96]

Isn't that what he said?

He might have?
I took it as "fuses" rather than "fuse". Meaning "fuses" for each of the aux outputs

I would type it as

main battery -> big fuse -> heavy cable -> isolator -> heavy cable -> big fuse -> aux battery -> fused aux outlets.

Cheers

 

[KraftyPg]

Do you own a fuse making business?

 

[justdrinkbeer]

Definitely fuse both ends of the cable running between the batteries, you definitely don't want that shorting out with no protection, I also fused the bit running to the fuse box for my aux items, I recon you can't be too careful around car batteries

 

[nathan96]

Do you own a fuse making business?

Yes I make my living off of selling fuses to unsuspecting forum members

 

[KraftyPg]

I'll have 3 please

 

[Dave]

Do you own a fuse making business?

Be nice. It could be read a few ways.

Dave.

 

[KraftyPg]

The comment may have been laced with dose of smart arse but I it typed it nicely.

 

[Dave]

Lol, laced with a dose of smart arse.

Dave.

 

[nathan96]

LOL

I can see from your lower case lettering you were very nice not like those nasty capital letter angry people.

lacing your comments with information rather than smart arse may have been more helpful to the original poster.

...but not as fun

 

[KraftyPg]

Tony is here to give battery advice, I may not agree with it all the time but he's far better at explaining things than I am so after the initial question where I was wondering if maybe you had read it wrong and hoped I was helping out by highlighting it, the rest was pure bastardry on my behalf figuring the Op had a fairly decent answer.

BUT DAMMIT I WONT LOOSE MY COOL!!!!!

 

[Dave]

Na I just saying most of us dont get offended at what you say those who dont know your personality to well could easily take it to heart.

Dave.

 

[KraftyPg]

Well would it now be appropriate to say F$%& Em!!!!!!!!!!!!!!!!!!!!!!


2 batteries and 3 fuses with wire between them (thread back on course now)