3rd battery

I'm looking to fit a third battery. currently got two optimas with the yellow running all the auxiliary stuff. I've got a big leisure battery rated at 110 Ah and I want to connewct it with the yellow one which I believe is rated at 55 Ah, could I just connect the two or will it cause problems, I've got an 80 amp alternator and a split charge system

Jesus, what you got, a power station in there!

personally Id directly connect the 3rd battery to the alternator otherwise your split charge may not give enough welly to the other 2 batteries...and get a bigger alternator if necessary...work out the amp draw of all 3 batts combined

but why do you need 3? why dont you swop the 55ah yellow for the 110ah leisure?

ive got a 60 litre engel fridge freezer, laptop, inverter running tele and wii game, winch and some form of music system, (got an 11yr old daughter who can't survive without Hannah Montana), just happen have a very good leisure battery and wondered if i could connect the two batteries after the split charge sytem without causing issues

as for swapping the yellow one for the 110 amp, it wont fit, but i've found a place for it elsewhere

should be ok i reckon but never done it or know of anyone doing it...i run similar to you with no probs on a 100ah leisure but i have solar panels also to assist recharge.
but my alternators 120 amp though...

so you dont see a problem with the difference in Ah, would one battery try and pull more than other or would they charge in harmony with each other

thats the bit im not sure about!

same here, how would i connect direct to the alternater?
sounds safer to me, would only charge when engine running, but could it then discharge the original starter battery?

yeah i reckon it would, unless the cranker is bigger in ah, but then if theyre both connected to the alternator, it would start off both of them if you connect the positive to the crank battery aswell....make sure you connect them in parrallel though otherwise youll end up chucking 24volts through everything!
To connect Id earth to chassis & find the charge wire off the alternator & run an extra cable off the same connection at the alternator end to the 3rd +ve terminal

ive got a big marine battery as mi 2nd batery
i dont run a winch from it but do run mi work lights,laptop,cb
and ywo mobile charges
and mi interior strip lights
seems ter cope no probs
have a manual split charge where i swap from alternator charging on ter the other by a switch as required
used it on 10 day trip last year camping wi kids no probs

i was thinking of fitting a couple of kill switches to break the earth on each battery so only one will charge at a time,

bevhelee said:

i was thinking of fitting a couple of kill switches to break the earth on each battery so only one will charge at a time,

Click to expand...

then you could connect it up through the existing split charge then...which would be less work with cables etc

is that a vote of yes then

go for it

***UNDER NO CIRCUMSTANCES WILL ANY CLAIM OF ELECTRICAL HARM TO VEHICLE OR PERSON BE MADE IN VIEW OF MY OPINION***

what i figured was that with killswitches in line i can control which battery gets charged and wehen we stop i can easily connect the two together for running everything, thanks for your help. Lee

sounds like a plan, no worries

thanks buddy

Just a thought Lee, (though might be incredibly stupid like a lot of my cunning plans)

How about a small charger that will run off the fag lighter socket as in one of those portable battery packs?? then you can run leads where you like with nothing hard wired.

No doubt if I'm talking total crap someone will point it out

frog hopper said:

Just a thought Lee, (though might be incredibly stupid like a lot of my cunning plans)

How about a small charger that will run off the fag lighter socket as in one of those portable battery packs?? then you can run leads where you like with nothing hard wired.

No doubt if I'm talking total crap someone will point it out

Click to expand...

thanks roger but would i then just be charging one battery from another

Not good with electrics. Know nothing about split charge systems. Probably shouldn't be posting on this thread. But if you're worried about connecting the 110ah directly to the alternater and it drawing more current than the two on the split charge system why not work it like this.

Alternator goes to a new split charge system. One half goes to 110ah battery. One half goes to the existing split charge system connecting to the other two batteries.

As I said, I know nothing about electrics, so please don't laugh.