# leisure Battery technology



## Bunglas (Oct 28, 2009)

Appreciate any help in choosing a replacement leisure battery in my Pilote MH. The original was a Banner Energy Bull 95a/hr. I have looked at the Elecsol, somewhat pricy but claims greatly enhanced service + a 5 year guarantee. I have also read about 'Absorbed Glass Technology' but don't really know the advantage/ cost trade off. Finally, while the on board charger can be switched between Gel/ lead acid, as the starter battery is not gel, I believe one should not mix both technologies.
Many thanks, in advance


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## neilbes (Oct 16, 2006)

Go for a Elecsol ..you cant beat em


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## CliveMott (Mar 10, 2008)

I will try.
Currently all battery technologies used in motorhomes are Lead Acid based. This could change in the future as lighter batteries with much more storage capacity are getting cheaper.

Starter batteries are designed to provide massive currents for relatively short periods of time and to be re-charged almost immediately afterwards at quite high charge currents. To facilitate this the structure of the lead paste laden plates is very open to present maximum surface area to the acid which forms the electrolyte. This also makes the plates easy to damage, especially if left in a discharged state for any time. In normal,use a starter battery is only ever partially discharged during starting but is maintained at about 80% charge by the vehicle alternator.

On the other end of the scale are TRACTION DUTY batteries designed to provide the motive power for vehicles like milk floats and fork lift trucks. Or in a smaller size to power golf buggies. These batteries are designed with a much more enclosed plate structure to enable them to withstand discharging down to about 20% remaining capacity then re-charged overnight every day and to have an expected life of 5 years.

In the middle are Leisure Duty batteries. These are essentially starter batteries but with a plate structure aproaching that of a traction battery.

All these battery types are available with conventional wet electrolyte and wet electrolyte does provide the best battery performance because it can mix when its in use.

If charging systems are used to fully charge the battery then periodic checking and topping up of the electrolyte is required. To minimise this "re-combination caps" can be used for the cell tops and these convert the hydrogen and oxygen gas generated during the last phases of charge back into water which falls back into the cell.

Some other "maintenance free" batteries use a gelified electrolyte and as such no maintenance is possible and special charging techniques employed to suit them. Other batteries have the electrolyte in a form of fibreglass blotting paper called Absorbed Glass Mat (AGM) and these are generally treated in a similar manner to GEL batteries.
Another technique is to use carbon Fibre re-inforcement of the plates to keep them together and this can be beneficial if its expecred to regularly deeply discharge the batteries. These batteries tend to have a wet electrolyte and Elecsol are one maker of this type.

If you are starting with a no battery situation are are thinking of having two leisure batteries to double up on your capacity then my preferance would be two 6 volt golf buggy wet electrolyte traction batteries fitted with re-combination caps and connected in series.

Does that help?

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

C.


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## gaspode (May 9, 2005)

Go for the cheapest lead/acid leisure battery and change it more regularly, 99% of users wouldn't notice the difference anyway.


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## neilbes (Oct 16, 2006)

You obviosly know your stuff Clive. So I stand corrected..

elecsol are a good replacement for standard leisure batteries


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## Bunglas (Oct 28, 2009)

CliveMott said:


> I will try.
> Currently all battery technologies used in motorhomes are Lead Acid based. This could change in the future as lighter batteries with much more storage capacity are getting cheaper.
> 
> Starter batteries are designed to provide massive currents for relatively short periods of time and to be re-charged almost immediately afterwards at quite high charge currents. To facilitate this the structure of the lead paste laden plates is very open to present maximum surface area to the acid which forms the electrolyte. This also makes the plates easy to damage, especially if left in a discharged state for any time. In normal,use a starter battery is only ever partially discharged during starting but is maintained at about 80% charge by the vehicle alternator.
> ...


Very comprehensive response. I will check dimensions of battery compartment to determine if I can fit 2 X 6 volt batteries.


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## Bunglas (Oct 28, 2009)

neilbes said:


> Go for a Elecsol ..you cant beat em


I like the simplicity of your solution, as you say Clive is clearly comfortable with the subject - I am not! Thanks again


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## nicholsong (May 26, 2009)

Thanks Clive Mott for your explanation - good as always. So I have saved it for future.

I do not want to cause any type of disagreemetn between two very useful contributors to MHF, both of whom have given advice useful to me.

Gaspode's posting in no way contradicted Clive Mott's advice, but was directed at the practical economics of the decisions that we all have to take on cost/benefit. 

Could I please ask for some expansion of this aspect?

NEW POINT , but I think not "Off Topic, since it is referred to in Clive's link

Clive is often referring to increasing cable size to reduce voltage drop. This I understand, but I do not know what size I have already and, as I understand it, the calculation of cable size in sq mm is quite complex and cannot be easily measured with a tape. 

Even when I have established what cable I have, how do I establish what size I should be upgrading to for optimum efficiency?

Last question (REALLY!) Why do MH (and marine) manufacturers not adopt 24v systems like trucks? It might solve a lot of the problems that we are dealing with here.

Geoff


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## CliveMott (Mar 10, 2008)

The cable size is written on the reel it comes off!

Seriously, consider the orange flex that is used for a hookup between the van and the hookup post. If you remove the connector partially to see the size of the three copper conductors this will be 1.5 mm sq.

The size of the normal battery connections in many motorhomes is about 4mm sq. Some if you are lucky will be 6 mm sq.

Some big A class vans that have the battery a long way from the starter battery use 10 mm sq.

The current rating of all these cables is well in excess of the currents that are likely to pass, the reason for having such a large size cable is this.

When you are driving and your "split charging" is working then the cable from your leisure battery gets connected to the starter battery via a relay.
Any resistance in the cable will result in less of the alternator output amps getting to the leisure battery. So bigger cables mean less resistance and a faster charge of your leisure battery.

Alternatively fit a B2B charging device. Now manufactured by Sterling and CTEK.

C.


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## nicholsong (May 26, 2009)

Sorry Clive, but were you pulling my leg? I wasn't there to see the cable drum when they built my Arto, and even following your advice on sizes I do not know from looking at the cable what size I am looking at.

My 'van is a N+B Arto 69 (2003). Does that fit in your classification of the 'A' Class which you say have the 10 sq mm cable?

You also mention the B2B - Sterling etc., but I seem to remember that in another thread you advised somebody to up their cable and relay sizes before spending £100 or so on a B2B. Which is why I have been looking at the bigger cable solution first.

Can you please clarify for me. Apologies if I have misunderstood something.

Geoff


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