# Adding a 2nd Leisure Battery - How to wire up please?



## Double-Entendre (May 19, 2009)

Hi.

I have a '96 Swift Royale and according to the wire diagram (Thank you mick from Swift), the feed for the Leisure Battery (LB - in case I have to type it again!) seems to come from the Alternator's "Low Charge" warning wire, via a relay, with the -ve going to the Cab Battery and to Chassis Earth.

As I undestand, this is so the LB is not called upon to turn the starter motor, with charging power only being split to the LB once the Alternator is spinning

Can I simply attach the +ve and -ve of the 2nd LB to the corresponding wires on the 1st LB, as they would, in my non-electrician mind, be going to the same place? Thus giving me 220AH @ 12V (Based obviously on 2 x 110AH LB's)

One chap suggested that you MUST attach both the LB's -ve leads directly to the chassis but I can't see the difference.

Looking forward to enlightenment . . . . .

Thanks


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## rayc (Jun 3, 2008)

Connect the +ve of the 1st battery to the +ve of the 2nd battery and the -ve of the 1st battery to the -ve of the 2nd battery.
Use suitable sized leads e.g that will handle 20 amps, there are plenty of battery leads sold on ebay. You could also install a 10amp fuse in the +ve connecting lead.


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## CliveMott (Mar 10, 2008)

Like this 
http://www.motts.org/second leisiure battery.htm

Take care
C.


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## DJP (May 9, 2005)

> Like this
> http://www.motts.org/second leisiure battery.htm
> 
> Take care


I would also advise before going this route that you check the cables from the ECU van charging unit (for mains charging) are of sufficient rating to handle the charging amperage that may be required for charging 2 or more liesure batteries.
You may need to run a seperate pair of leads from the ECU to the additional battery/batteries.


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## rayc (Jun 3, 2008)

DJP said:


> > Like this
> > http://www.motts.org/second leisiure battery.htm
> >
> > Take care
> ...


Surely the charger can only supply its maximum rated current whether a single or dual batteries are fitted. My charger can give up to 16amps and the cables are more than adequate for that.


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## AberdeenAngus (Jul 26, 2008)

Try and make the batteries as similar as possible. If your existing battery is getting on a bit, you may consider getting two identical ones or even, better still, one huge one !

Differences between the batteries can result in one discharging into the other.


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## DJP (May 9, 2005)

> Surely the charger can only supply its maximum rated current whether a single or dual batteries are fitted. My charger can give up to 16amps and the cables are more than adequate for that.


I can only speak from experience. I was advised by Sargent (the charger unit manufacturer) that when I wanted to install additional batteries NOT to connect them in parallel as suggested. I was told to run another separate twin cable from the additional batteries to the charger box as the cable was not of the correct rating. In the end, the dealer wired the extra batteries in by connecting them to the control box which sits behind the drivers seat as it has spare terminals which connects to the charger.


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