# Adding an additional Leisure Battery



## Welshcampsite (Jul 20, 2009)

We have a Roller Team Pegaso 181 and it is pre-wired for an additional Leisure Battery under one of the seats.

Questions:

1. Currently I can switch between Bat A (Engine) & Bat B (Leisure) on the Control Panel to check the voltage of each, if I add Bat C will this be listed automatically?

2. By adding the second Battery, do the two Leisure Batteries work alongside each other or does the second one only come in to play when the first is flat?

Thanks for any advice.


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## philjohn (May 29, 2005)

Hi,

If you add a third battery ie your second leisure battery the two batteries will show as one and work as one, as they are in parallel they will still only be 12 Volts consequently you will not get a third battery on your display.

Hope you can follow that,

Phil J


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## Welshcampsite (Jul 20, 2009)

philjohn said:


> Hi,
> 
> If you add a third battery ie your second leisure battery the two batteries will show as one and work as one, as they are in parallel they will still only be 12 Volts consequently you will not get a third battery on your display.
> 
> ...


Same voltage just more capacity? OK that makes sense.

many thanks


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## robrace (Jun 30, 2005)

*2nd battery*

Did exactly the same myself last month!You end up with the same voltage aprrox 12volts but greater amps.The 2nd battery will only give the same as the original.Ie put a 75amp battery with a 100amp you will get 150 amp not 175amp according to my battery supplier!


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## DABurleigh (May 9, 2005)

You might like to quote your battery supplier here, so we can all avoid such battery expertise.

Dave


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## Guest (Jul 23, 2009)

philjohn said:


> Hi,
> 
> If you add a third battery ie your second leisure battery the two batteries will show as one and work as one, as they are in parallel they will still only be 12 Volts consequently you will not get a third battery on your display.
> 
> ...


Make sure that you DO connect them in parallel (i.e. +ve to +ve) rather than series (+ve to -ve). Series is a good way to get 24v whether you intend to or not!

Tco


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## CliveMott (Mar 10, 2008)

More on :-
http://www.motts.org/second leisiure battery.htm
C.


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## chasper (Apr 20, 2008)

So what would be the problem joining a wet and a maintanence free battery in parallel? PS off to Germany tomorrow to get a new avatar to replace my old one!


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## DABurleigh (May 9, 2005)

Two problems (well apart from wet and maintenance free are not mutually exclusive as you imply, but I understand your gist)

1) The charging characteristics need to be matched to the battery type/construction. That's why many chargers have a switch to select. Get it wrong and the life of your expensive battery can go over a cliff but in a less satisfying way thatn throwing it over one.

2) During the charging and discharging cycles, batteries in parallel should exhibit very similar effective internal resistance, otherwise the charge currents are different, and again, battery life suffers.

It is possible for them to cope when wired in parallel, but only with some resistance between them, very similar to the separation one gets between vehicle and leisure battery. You need to think things through carefully.

Dave


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## AL8 (Feb 16, 2009)

Welshcampsite said:


> We have a Roller Team Pegaso 181 and it is pre-wired for an additional Leisure Battery under one of the seats.


What an excellent idea by the manufacturer. I wish mine was pre-wired *GREEN WITH ENVY*


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## DABurleigh (May 9, 2005)

Do you not have the space, cabling bits, or knowhow?

Dave


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## AL8 (Feb 16, 2009)

DABurleigh said:


> Do you not have the space, cabling bits, or knowhow?
> Dave


plus time and plan. 
But seriously I have the skill just not the experience. The 2nd battery would need to be inboard (under the bed), not sure if that requires extra venting or a battery box, or both? Wiring would be easy I'm sure, I've no plans of an inverter, so, I guess I'd just match what is there?

I must say that a 2nd leisure battery seems a very cost effective purchase. Made more cost effective if it was just a case of connecting up the battery, courtesy of a kindly manufacturers pre-wiring 

A winter project I think. Mainly because of: http://www.motorhomefacts.com/ftopic-69212.html


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## DABurleigh (May 9, 2005)

This may help:
http://www.motts.org/second leisiure battery.htm

Dave


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## AL8 (Feb 16, 2009)

I thought I give you an update...

I fitted 2 new leisure batteries, both purchased at the same time & both 110amp.

The 2nd (extra) leisure batt had to go under the bed, with only a relatively short cable run, but still I used the 3 fuse solution.

All in all it was very easy, I just needed to make the time to do it.

All the fuses have ended up inside in the dry..

Sourcing the right gauge wire & fittings was a bit of fun - but, of course, very necessary.

So I've gone from a knackered 85amps to a heart warming 220 amps.  

Thanks to all those on MHF that have posted regarding a 2nd leisure battery, I've read 100's of posts and they all helped to get my a**e into gear  

But it has lead me to think about the whole charging thing, so here goes.

Assuming, everything is working ok and that the vehicle battery is good & was used a week ago .... If one drove for 4 hours in the evening at this time of year; so lights on, heater on a trickle, wipers (maybe) & radio - how much of the time would be charging the vehicle battery & therefore, how ?little? time would be left for charging the leisure batteries.

I know that an exact answer is not possible but what would your guesses be.

I think that with the constant drain from the vehicle battery because of, inparticular, the lights & heater fan, I fear there will be very little 'spare' charging available fror the leisure side of things - I'd say less than 25% - but I don't base that on any fact - just a lot of thinking.

What do you think?


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## Jezport (Jun 19, 2008)

You can get single batteries with 230 AH, thus avoiding extra wiring and mixing a new battery with an old one.


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## DABurleigh (May 9, 2005)

You're not far wrong. I reckon you could get 35+ amps on discharged batteries even with other demands on the alternator. But it's a bit of a wet finger guess.

Dave


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## AL8 (Feb 16, 2009)

Jezport said:


> You can get single batteries with 230 AH, thus avoiding extra wiring and mixing a new battery with an old one.


I don't think I could have fitted one in the area of the old 85A battery, the 110A only just fitted & I think that the 200+ ones are proportionally larger - although I'm not 100% sure. But, YES, if you've got the space the cost of 1 large capacity battery seems to be about the same as 2 'smaller' ones - especially when you add on the clamps, box, wiring etc and much easier.



DABurleigh said:


> You're not far wrong. I reckon you could get 35+ amps on discharged batteries even with other demands on the alternator. But it's a bit of a wet finger guess.


I think I might arrive with the leisure batteries as flat as when I started - or at least nowhere near charged. And never put back nightly usage.

Solar here I come


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## peejay (May 10, 2005)

AL8 said:


> I think I might arrive with the leisure batteries as flat as when I started - or at least nowhere near charged. And never put back nightly usage.
> 
> Solar here I come


Depending on your touring habits, solar isn't the be all and end all, you might also like to consider a sterling battery 2 battery charger.

>Sterling B2B<

Pete


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