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third battery hookup

Posted: 13 Oct 2010, 18:27
by tee3peeo
I have a `14" T25 syncro. I've attached a leisure battery and linked it in the usual way. I've connected a feed from the alternator to a relay and then the positive and negative from the main battery via the relay. The question is this. Can I link another battery? I've got a spare which I would like to keep charged. How do I connect this one to the system I've described. I would be grateful if anyone coul;d offer tips or a links to a diagram.

cheers
Zeb

Re: third battery hookup

Posted: 13 Oct 2010, 19:02
by kevtherev
Yes you can...
just connect the battery in parallel.

It would help if the third battery is of similar Amp hour rating

Re: third battery hookup

Posted: 13 Oct 2010, 20:02
by tee3peeo
Hi Kevtherev,
thanks for reply. So - parallel, pos to pos, neg to neg - do I need to add another relay? The amp hour rating is different tho. The second battery is a leisure battery about 115 I think whilst the third would be a starter battery - about 65, is it vital?

cheers
zeb

Re: third battery hookup

Posted: 13 Oct 2010, 20:12
by kevtherev
yes it matters to some degree that they are similar, as they discharge at different rates so would be unequal when charging.
Your Alternator would favour the most discharged battery, so the others would loose out.

however if that doesn't matter to you, because you just want to keep it topped up.. then just do it. no relay needed just connect them like you say

Re: third battery hookup

Posted: 13 Oct 2010, 21:45
by tee3peeo
thanks kevtherev

zeb

Re: third battery hookup

Posted: 13 Oct 2010, 21:50
by davidharvey
would they both not just charge as said to lowest level....ie 65 amp, so therefore not much a gain over the single 115 amp leisure battery? (65x2=130)

Re: third battery hookup

Posted: 13 Oct 2010, 21:56
by CovKid
you can also get smarter relays that will charge two leisure batteries.

Re: third battery hookup

Posted: 13 Oct 2010, 21:57
by kevtherev
indeed but if he disconnects the smaller of the two once charged they could be recharged in a staggered fashion