# Leisure Batteries bank



## GAVLAD (Aug 10, 2014)

Hi,

With a bank of leisure batteries - do all batteries have to be the same amp hours/AH's?

I have five leisure batteries on my new motorhome, two of which are 110ah and the other three are 95ah.
All are sealed units and all linked to make one big 12v battery.

I've been advised that leisure batteries should be the same AH, as it messes up the charging system when some are different to others.

I would have thought that once a battery had been charged up, it would focus on the other battery and so on, before then topping up the vehicle battery.

Any ideas?
Also, there's not a massive difference between 110ah and 95ah - I can understand it if it was 110ah and 45ah - but maybe I'm wrong?
What's your thoughts.

Just FYI, current charging system is the factory fit system and I am looking at adding a solar panel/charger as well.


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## p-c (Oct 27, 2007)

Hi
There was a recent topic on this.
I doubt a standard fit leisure battery charger in a MH would have enough oomph to charge 5 batteries. I think you will find that all the batteries charge at one go, it does not charge one then the other etc.
Why 5 leisure batteries? Weight, space, sounds a lot.
Regards
p-c


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## rayc (Jun 3, 2008)

> GAVLAD said:
> 
> 
> > Hi,
> ...


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## p-c (Oct 27, 2007)

Found it

http://www.motorhomefacts.com/ftopict-244154-.html

p-c


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## GAVLAD (Aug 10, 2014)

Thanks for the link, I will have a look at that now.
Not sure as to why there's give on it.
I know two came as standard from the manufacturer and the other three were added by the previous owner. Not sure whether they lived off grid all holiday or what?


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## Mrplodd (Mar 4, 2008)

I would take your new acquisition to a weighbridge. Most leisure batteries weigh in the region of 25kg so your enormous bank of batteries weigh in at 125kg (that's 2.5cwt or an eighth of a ton in old money )


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## GAVLAD (Aug 10, 2014)

Hi
Already done that and still well under payload limit.
I've a public weighbridge local to me and they kindly weighed the front and rear axles as well. All well under the limits.


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## Yaxley (Jul 25, 2008)

When it comes time to replace the batteries I would drop at least 2 of them and install a solar panel.
Ian


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## powerplus (Oct 6, 2014)

hi

i recently fitted a additional battery to my motorhome, as the battery was a smaller a/hr to the fitted lesure battery 

i linked them, plus to plus - neg to neg and installed a battery switch to separate them

i did it this way so that the 2 battery's would not fight when when not in use

this way i can charge both battery's after use and then switch the smaller battery off of the circuit

to keep it topped up i will switch on the second battery for a couple of hours once a week

i will only use the smaller battery if i need to use the inverter ,

in time when the battery's are done and replacements are fitted i can just leave the switch on or remove it

hope this makes sense

barry


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## listerdiesel (Aug 3, 2012)

It is not so much the size of the batteries as the type and their condition.

We have 450AH worth of AGM batteries going in the Mercedes and we are fitting a 50A power/shore supply which acts as a charger as well. 

A 16A charger is really too small unless you are only discharging by 10-20%, in which case you don't really need all that capacity.

As all the batteries are charged and discharged together, they will not be at different voltages, the charger just sees the whole assembly and cannot determine or charge any one out of the set.

Peter


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## powerplus (Oct 6, 2014)

hi peter

im glad you came in on this one

barry


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## 79144will (Sep 8, 2010)

Listerdiesel,can you give me an idea of the size of charger I should have to charge two off 230 ah batterys,the German one,the original charger was 35 amp,Thanks Bill


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## listerdiesel (Aug 3, 2012)

460ah at minimum 10% charge rate in amps would be 46A charger, but if you don't run them really down it will do the job for you.

The danger in undersized charging facilities is that the battery never gets up to full charge and on a trip you will find the available capacity reducing day by day.

You could supplement your 35A charger with another bulk charger in parallel, just use the extra grunt when needed.

Our 50A charger is a single-rate power supply that acts as a shore supply when we are on EHU.

We also have solarm 4 X 100W panels.

It is vitally important for good battery life and performance to keep the batteries well charged at all times, and recharge as soon as possible after discharge.

Peter


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