# Adding another leisure battery



## TheBoombas (Aug 23, 2006)

Thinking of adding a second 110amp Leisure battery.
The existing one is ok and only 11 months old. Is it ok to get another battery and parrell them together or should I / is it best, to get two new matching batteries?
does the new one have to be the same ampage of can it be larger?

Brian


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## gnscloz (Oct 4, 2008)

hi,
best get battery as close as exsisting battery as possible, ie gel wet lead etc, no good getting bigger one because it will only charge to exsisting battery, fit in parallel


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## bob44 (Mar 9, 2006)

Hello BJ,

Amost the same subject was discussed here recently:

herehttp://www.motorhomefacts.com/ftopicp-650458-.html#650458


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## DABurleigh (May 9, 2005)

When batteries are charged and discharged in parallel, it is very important, in order to maximise their life, that the effective internal resistances, throughout the charge/discharge cycle, are also closely matched. 

The best way to do this is to get identical new batteries from the same batch. Getting progressively away from this, the next best:
Identical new batteries from different production batches
Same make and model new batteries, but different capacities
Nearly new and new, but otherwise identical
And so on.

Yer pays yer money and takes yer choice 

Dave


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## yozz (Jan 18, 2009)

BJNorris said:


> Thinking of adding a second 110amp Leisure battery.
> The existing one is ok and only 11 months old. Is it ok to get another battery and parrell them together or should I / is it best, to get two new matching batteries?
> does the new one have to be the same ampage of can it be larger?
> 
> Brian


Hi Brian can I ask why you want a second leisure battery?


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## CliveMott (Mar 10, 2008)

Have a look here as well.

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

C.


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## TheBoombas (Aug 23, 2006)

yozz said:


> BJNorris said:
> 
> 
> > Thinking of adding a second 110amp Leisure battery.
> ...


We dont do a lot of hook-ups. 
Wil be on site for maybe a week in Sept Running all the normal stuff LED Lights, TV, Blower - Audio etc, May not need the extra capacity, but it's nice to know you have it. Can.t let Mrs Boombs miss Emerdale can I..... Can I!!

Brian


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## thePassants (Feb 9, 2009)

Hi Brian,
6 Months ago, when we got our 4 yr old MH, it came with a (probably original) 86Ah leisure battery.
It has the little indicator, and still shows green; for OK.
Like you, I wanted a 'bit more reserve' so got a 110Ah Bosch leisure battery from Costco.
Since the old one still seemed OK, I paralleled them; with a Double Pole Isolator between, incase I had to take one out for some reason -not to have live leads sitting around.
I didn't know about 'matching' batteries etc. , but have had no problems, and plenty power; with any luck the Bosch battery will knacker just before the Costco 2yr guarantee runs out. :lol:

It works... :?
-and from tomorrow we're full-timing for 3 months, so will see how it goes!


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## lgbzone (Oct 8, 2008)

CliveMott said:


> Have a look here as well.
> 
> http://www.motts.org/second leisiure battery.htm
> 
> C.


Clive

Very informative, short, sweet and clear.

Thank you

Lee


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## 124730 (Jun 17, 2009)

I have 3 (now 4!) aux. batteries for those awkward days when there is no (expensive) hook-up. This will happen even more this year in Germany where "free"(ish) sites are common.
My batteries are not matched and I have no problems, but make sure there are fuses between each one, and have changeover switching so that they are normally not connected to each other, and can be charged separately. My 43 w solar panel charges whichever is connected.

A 0.01 ohm (5w minimum, 10w preferred) resistor in each battery lead would counteract risks due to unbalanced batteries, without significant loss of energy. These could be used as the dropper resistors for monitoring current drains and charging current on individual batteries (see other posts).
Anyone know a suitable source?


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## HarleyDave (Jul 1, 2007)

Have a look here

http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=2508456883

Cheers

Dave


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