I agree with oldbobsbus. The only stipulation I can recall from my RAAF days is the batteries must have the same AH capacity and connected in parallel (ie. pos to pos and neg to neg) be very careful when installing them.

Safe travels

Sorry but duell battery system's are a new thing to me, never really been interested but since getting the new tug I have started thinking duell battery. However, a couple of comments in this thread have confused me and that's not hard.

I thought when connecting two batteries together you must have same AH size and as close to same age batteries then connect possitive to possitive and negative to negative, with heavy duty cable of course. If I am reading comments in this thread right one says one way and another says another way, HELP me please but don't hurt and make it simple PLEASE.

I have also seen on-line that you can fit it on top of the rear left wheel arch in the back tub of the RG Colorado Crew Cab.

-- Edited by Dougwe on Sunday 22nd of June 2014 12:46:50 PM

I may have confused you Mr Doug...

The batteries need to be connected as everyone else said, it is just better to be sure you are using both batteries by taking OFF from different batteries that way you are making sure you are pulling off both batteries and not just the closest one as someone found out here a couple of months ago becoz they had the batteries tooo far apart and the connecting cables weren't doing their job..

I have a dual battery system in our caravan. I replaced the 8mm squared cable between the batteries with 2 x 10mm cables, thus decreasing the voltage drop (the length is 300mm), not happy that the van builder chose the smaller cable diameter.

In my mind the heavier the cable the less volt drop which will reduce the heat effect etc.

A fact of life is that the two batteries will never be exactly the same so one will charge the other by a small amount. No big deal as long as the AH capacity, voltage and I would say brand are the same.

Be very careful with the leads when you hook them up. Do one at a time wont cause a short that way.

Safe travels..

Thanks Peter. All info seems to say the same and I am grateful for all of it.Regards Ray

oldtrack123 wrote:

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RLLakeside wrote:

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Hi guys

I need info on duel batteries. At the moment I have a 95 amp battery in my avan poptop it also has a solar panel attached on the roof I would like to change this  to two 105 amps ones joined  together the reason being is that i have them at home one to power my electric motor and the other one is in my 4x4 both being 12 months old. So then I can use the 95 amp one for my elec motor. I like to think that i can do this BUT im just asking to confirm it

Regards Ray (new newbies)

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HI Ray

 No problem with that as long as you parallell conect the two 105Ahr batterries

That means connecting the Negs together & the Pos together with short heavy  cables of the same length

Then preferablly taking the load pos from one battery & the load Neg from the other battery

This is not essential with light loads as you will probably have, but is GOOD practise!

 While battery suppliers suggest changing all the batterries to the same size , type ,brand ,[It is good for their profits] 

in practical terms there is usually no problem with connecting different Ahr , aged or brand batterries in PARALLELL.

It is just that the aged battery may failure  & pull the other battery down with it .

BUt that can /has happened with even all new batterries.

However, being the same type is more important ,the batterries should have the same charging requirements.[fully charged voltage,

Float voltage]

PeterQ

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 What he said 100%