Dual Battery System - What do you run of main battery ?

Davidman

5th Annual Victorian Gathering member
Hi All,
I am going to be installing a dual battery system into the NJ Pajero. Reading through forums on this site, and others, it appears that what a lot of people do is to run all or most power to accessories ( cig lighter sockets, UHF rdio, power inverter etc etc ) from the second battery. This leaves the first battery to start the thing and run the stock standard items.

Not being overly familiar with the set up, is it as simple as adding a second fuse box under the bonnet and getting power for this from the second battery. Accessories etc can then be run from this fuse box with less chance of inadvertently draining the main battery.

Also, when wanting to run stuff from the second battery ( which currently goes through the main / stock fuse box ), is it as simple as moving the wires from the stock fuse box over to the new fuse box and away you go.

Haven't decided on battery tray or battery as yet. Still have to move the charcoal cannister across to the other side first.

Any comments on what setup you guys have would be great. I am looking at a Redarc or similar 150 Amp electronic system. Am open to suggestions.

Thanks
 

Pure Yobbo

Moderator
Seems like a good system the redarc I run a different one but other I know love the redarcs.

I have installed another fuse box under the bonnet as everything really should have a fuse.

You sound as though you are on the right track with what to run off the second battery.

Cheers
 

Traveller

Well-Known Member
Maybe if you're not a great hurry, you could have a look at a few systems on 17 May at the bbq.
I run two starting batteries, with a mixture of acces. off each.
 

Grumpy

Moderator
I run Standard things like Spotlights off the starting battery, things that would normally be ran if u only had one battery.

The second battery is used for winching, running the fridges and the rear light comes off this as well as the inverter if I'm using it.

Hope this helps.
 

Brisey

Member
It sounds like you have the right idea.

Here is a link to an article about dual batteries I wrote a few years ago for the camping WA forum. Just the basics but interesting reading.

Dual Battery Systems

Cheers

Bri
 

4x4junki

New Member
Definately sounds like you are on the right track. The more you can remove from the starting battery and add to the second the better.
 

centaur

Member
You are definitely on the right track.

I have a dual battery system in my HJ60 Diesel. It runs a Redarc isolator. The main battery is a calcium battery, and a normal lead acid battery for the aux.

I have the main battery just running the normal single battery stuff. Then I installed a second fuse box on the aux battery runs that the twin CB's, Spotlights and the Aux connection in the back. It is necessary to run a seperate fuse box, everything should have a fuse.

Mine works a treat. I have just installed a 3 way switch for the radios, so when in normal use, they run off the main battery, but when stopped, or engine not running, I flick a switch, and then they both run of the Aux battery.
 
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rodw

New Member
I run Standard things like Spotlights off the starting battery, things that would normally be ran if u only had one battery

What he said

The second battery is used for winching, running the fridges and the rear light comes off this as well as the inverter if I'm using it.

You should not connect your winch to the Aux battery as the Solenoid (eg the Redarc or whatever you use) is usually only rated for 100 Amps and the winch can pull far more than that so you will blow something up. If you are running a winch, look for a solenoid (like the newer Redarcs or the ARB one like mine) that allows you to add a "link switch" that hooks the two batteries together. Use a momentary switch and push it in while winching (or if you want to jump start the car from the Aux battery).

As far as power distribution goes, I made one up from a fuse box and a 100 amp maxi fuse holder from Supercheap.

807885_image1003.jpg


I bent over the lugs on one side and soldered this to the Maxi fuse. then I added an eye for the battery on the other end

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I cut a groove in a piece of counduit and filled it with Silastic and taped it on and let it dry overnight.

452914_image1001.jpg


ARB installed my dual battery system initially and just ran it to the fridge. Here is the Link switch they used and the heavy duty marine cig lighter I added that is wired back to one of the fuses.

656192_image2-002.jpg


I mounted it all nice and close to the battery so the wire to the Maxi master fuse was as short as possible to minimise the possibility of a short.

394372_IMG_1292.jpg


Brisey's article is pretty good. I might have to update my bible link from Fridge & Solar :)
This link suggests that there should be a 100 amp fuse at the battery end on each of the wires to the isolator. Maxi fuses like I have used are ideal for this but don't extend the fuse wire to the battery. In my previous vehicle, I followed the guidelines in this link which has the following diagram.
703384_Redarc%20car%20rear%20mount%202mega%20(Small).GIF
 

centaur

Member
Very informative read, well done.

I have one question. I have a redarc isolator, and it was installed by a auto sparky. I have a blue wire that hangs off the side of the isolator, and he said that when I want to use the aux to start the truck, I just pop the bonnet and touch this connection on the isolator to "jump start" the truck. Going by your article, does that mean I can switch this back to the isolator, saves me doing it manually? If so, once the blue wire is run to the switch, where does the wire from the switch go, back to the connection on the isolator?
 

Davidman

5th Annual Victorian Gathering member
Great article, thanks RodW, I like the look of your set-up.

I have pretty much decided on the redarc isolator and will be adding a second fuse box somewhere under the bonnet pretty close to the batteries. From this I will run all the non standard stuff, including the spotties on the bullbar. ( I currently operate these with a toggle switch wired into an always live connection - didn't go with wiring them to the high beam switch or anything - at least through the aux battery, if I ever forget to turn them off ( haven't yet ) then the cranking battery will be okay )

I might also run a second fusebox from the aux battery and mount it under the dash. This will allow me to plug the accessories inside the cabin into it without the need to run cables through the firewall.

Keep the comments etc coming. I would like to see an answer to Centaur's question

Thanks all
 

rodw

New Member
Very informative read, well done.

I have one question. I have a redarc isolator, and it was installed by a auto sparky. I have a blue wire that hangs off the side of the isolator, and he said that when I want to use the aux to start the truck, I just pop the bonnet and touch this connection on the isolator to "jump start" the truck. Going by your article, does that mean I can switch this back to the isolator, saves me doing it manually? If so, once the blue wire is run to the switch, where does the wire from the switch go, back to the connection on the isolator?

I have not used the Redarc, but I think you would simply run the blue wire back to the switch and then earth the switch. Was he saying touch it to the body of the Redarc or to a terminal on it? The body is probably earthed. Anyway, check out Redarc's web site for more info.

Make sure you use the momentary switch as the isolator is bypassed in this mode so if you were to leave it on it won't be doing it's job at all.
 

Davidman

5th Annual Victorian Gathering member
Quoting from the Redarc installation instructions

" We suggest installing the emergency start switch on the dashboard of the vehicle. Connect a wire from the over-ride (blue) terminal of the smart start to a momentary push button switch. Connect the opposite side of the switch to the auxillary battery supply. It is recommended to fuse this wire. To manually operate the smart start, hold the switch and the smart start will manually operate until the switch is released "

As suggested in the post above, more info is available on the Redarc website.

Hope this helps
 

Croozer

5th Annual Victorian Gathering member
Talking about duel batterys. Im and going to have put them in the TI. Has anyone put a battery in the rear and how does the setup run. Have no room under the bonnet with the gas injection and the abs. Any info would be a help.
 

Davidman

5th Annual Victorian Gathering member
Thanks for all the input guys. Finished ( if anything is ever really totally finished ) installing the dual battery system tonight.

Ended up running a 65 amp hour battery ( couldnt fit anything higher under the bonnet and not rich enough to go for gel batteries etc ) and a 100 amp Redarc solenoid ( smart start ).

All wired up with an always live fuseblock under the bonnet and another in the cabin behind the kickpanel at the left of the passengers feet.

Have also installed an over-ride switch to 'jump start' if ever required and an LED into the dash which glows when the solenoid is open and both batteries are charging. Solenoid off and starter battery isolated means no glow on the LED.

Upgraded the cigarette ligther sockets to the heavy duty ones and rewired these individually into the interior fuse block, each with it's own fuse. This will allow the inverter, battery chargers, laptop etc to run simeltaneously without blowing anything.

Have also rewired the UHF, spotties, radio/cd and interior lights to run off the aux battery. UHF and spotties are always live while the interior light continue to work of the door switches.

Overall the whole process was pretty easy, just time consuming.

Again, thanks for all your help

David
 
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Sharky

New Member
Stuff me, you don't muck around do you? :D

I've done all that too except, the fuses & LED's etc. I've found over the yrs that you can go overboard & stick a fuse between every point of contact on every circuit & all you end up doing is forever be replacing fuses. And you do, believe me.......not at 1st but in 12mths time, it starts.

Anyway, it sounds like you've set it up well. I've got my UHF & Spotties (front & rear) always live, my interior light still uses the main batt but I'm concious of it, plus I have 2 big hybrid (semi cycle) batts. I don't use cig lighter sockets coz if you spend enuf time travelling on rough terrain you'll know how easily they can short out. I use utilux plugs (trailer type) or anderson plugs with an on/off switch on the dash, but I run them off the aux batt too, along with the stereo & DVD player.

I've never needed an override switch. I've certainly needed a jump start but when you think about it, your isolator switch keeps the batts disconnected until ign is in the 'on' pos & it takes a few secs for a faulty batt to really draw from the good 1 to a point where it'd impair jump starting abiltily. I just connect the jumper leads, increase the idle speed of the donor car & let it charge the flat batt for a min then I turn the key & immediately attempt to start the car being jumped.

I also have an anderson plug next to my trailer plug on the rear bumper, mainly as a charge source for the batt on my camper but it also acts as a jump start point from the rear, which has come in handy when the car is parked in a position (whilst camping) that restrains other cars accessing the front. All you do is make jumper leads with alligator clips on 1 end, & an anderson plug on the other.

I'm surprised so many people either fail to contemplate or shy away from mounting their aux batt in the boot. Batts last so much longer & work better when not exposed to heat as in an engine bay. A battery box costs $30 & conceals it nicely, although not every make of car has a place for it out of the way. If my car didn't already have dual batts set up under the bonnet I would've put it in the back for sure. But then again, I'm the sort that'll have a whole interior stripped out in 1hr to make it easier & conceal all wiring.
 
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wildgu6

New Member
In the process fitting dual battery at the moment, awesome write up guys, very informative and gives me a few great ideas. Nice work
 

mrdenn1s

Member
I run Standard things like Spotlights off the starting battery, things that would normally be ran if u only had one battery.

The second battery is used for winching, running the fridges and the rear light comes off this as well as the inverter if I'm using it.

Hope this helps.
I wouldn't run my winch off the 2nd battery. Need a high current battery like the starter. Running the winch off the 2nd will be bad for it.
 
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