Double Battery set up.

[muddyjames]

I had to buy a new battery just before Xmas as the one I bough the xmas before totaly died.

The battery I got from Halfrauds at £99 is one suitable for a td5 and only just fits in the space. I can't remember the size of it.

the battery I got last year I need to exchange (cant get refunds :( ) and is the usual battery that goes into a disco 1, so slightly smaller in size and oomf.

I have a mate who could sell me a twin battery set up kit.

Can I use 2 different size batteries? I have been told that both batteries must be the same condition. Being as I bought one less than a month ago and going to exchange the other this weekend hopefuly then they should be in same condition.

your thoughts please :D

[Yoshi]

IIRC when i looked into this it was said the batteries should be identical size and yield etc... etc... so i dont know.

[muddyjames]

could be a brand new battery up for sale soon then  :roll:

[Skibum346]

So how do camper vans and the like run double legth leisure batteries and a standard vehicle battery? 

Not an expert... but it seems to me the issue is whether one or the other needs charging and the charging circuits can figure that out.

It's the same "flavour" of electricity coming from the alternator... 

However.... I've been wrong before and I will be again... whether I am this time... who knows?! 

[chris9119]

I've run two different amphour (Ah) batteries before and no issues.

As Frank says, same flavour electric......

Like him, I've been wrong before........, but not many times  :lol:

[stageonesimmo]

If the very clever little boxes they sell that are supposed to work all this out, cant then they arent worth the money they cost are they?!!

I'm no expert, but not a novice either and I reckon its as simple as this - the alternator will supply the same voltage (roughly dependent on revs obviously) to how ever many batteries you have.  It will supply the amperage needed to each battery as it needs it same as it does with just one, (if one battery only wants 5 amps it doesn't produce 50 and throw the excess overboard, it just produces 5 amps), so if one needs more it'll get it and vice versa, all the clever little box of tricks does as far as I can tell is make sure each one gets what it wants and displays to you what its doing as it does so.

Stick with the ones you have and try it - I reckon it'll work fine.

[Range Rover Blues]

It's utter coblers TBH, you can use 2 batteries of any size as long as they are both the same nominal voltage (some fancy new types are slightly different).

When it really counts and you are dragging lots of current, the bigger battery will have the lower internal resistance and suplly most of the power.

If you have a split charge system then even better as both batteries are effectively isolated unless being charged.

[Landynuts]

I think that if you are using a split charge system then the batteries can be what ever capacity you want. How ever if you are connecting them in parallel then you will not get the full benefit as the higher capacity one will be dragged down by the lower one.

[muddyjames]

So I need a split charge system like in a caravan 12S socket?

[L90OOK]

So I need a split charge system like in a caravan 12S socket?

I would fit THIS if you are using different batteries.  If using the same batteries then wire in parallel. 

[muddyjames]

£40 for that. does look good. I will wait and see what my mate has as it maybe that component as his disco was well tricked up with winches etc. :D I think it wont be the parrallel route.

[Range Rover Blues]

if you are connecting them in parallel then you will not get the full benefit as the higher capacity one will be dragged down by the lower one.

 :-.