# Batteries inside the motorhome?



## jspencer (Feb 27, 2015)

Hi, I have just bought a 2008 Rimor motorhome and everything electrical seems relatively OK so far! The previous owner installed a 80W solar panel and an extra house battery that he had installed under the passenger seat. 
My question is that all the advice on having wet batteries inside the motorhome say you shouldn't do it due to the hydrogen risk. I was going to remove it and replace it with an AGM battery under the seating area. I then thought about the starting battery and realise it is factory installed under the drivers seat and is a traditional lead acid battery. 
Do I leave all well alone?

Thanks

Jon

P.S. I live in NZ and the motorhome club here is against wet batteries inside the motorhome.


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## Pudsey_Bear (Sep 25, 2008)

It's mainly an overcharging problem, they give off Hydrogen gas, which if you've seen the Hindenburg go up, you'll know it is highly flammable, but most MHs have them, and no problems, change if it really worries you, maybe wait until it needs doing or upgrading to larger amp hours.


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## listerdiesel (Aug 3, 2012)

As Kev says, it's only an issue if the batteries are overcharged.

We have two 12V 100AH wet batteries for the vehicle electrics (24V) and they are under the driver's seat. 

Peter


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## jspencer (Feb 27, 2015)

*Thanks..*

Thanks for the advice. I'll wait until they need replacing instead of spending many $$$ to replace perfectly good batteries. Parts aren't cheap over here and don't need any unnessessary expenses. 
Jon


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## trek (May 1, 2005)

I would want to see that the internal battery is vented to the outside

This is usually done via Clear plastic tubing that fits via a right angled fitting into the top of the battery at one end (the other end of the battery should have a bung in the hole)

This tubing then simply drops through a hole in the floor to vent outside


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## spykal (May 9, 2005)

Hi Jon

As has been said .... it is OK to have wet lead acid batteries fixed inside your motorhome BUT to be perfectly safe they do need a vent tube fitted that will take any hydrogen gas produced to the outside. 

Watch this video <<<

Edit ...must type quicker Trek beat me by a minute .... good advice though


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## Pudsey_Bear (Sep 25, 2008)

spykal said:


> Hi Jon
> 
> As has been said .... it is OK to have wet lead acid batteries fixed inside your motorhome BUT to be perfectly safe they do need a vent tube fitted that will take any hydrogen gas produced to the outside.
> 
> ...


I'm not sure that's correct, the tube is an overflow for expanding acid so as not to damage the battery tray etc, Hydrogen gas is lighter than air, so may pass through the tube, but I'm not sure it would.


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## Pudsey_Bear (Sep 25, 2008)

Also the terminology is confusing.

Valve regulated lead acid (VRLA) means no tube is needed, but they can still gas, best to just make sure the charger is good and you're well ventilated.


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## jspencer (Feb 27, 2015)

Thanks for all the quick answers, I don't think the starting battery is vented but I will check when it is light. I wonder why Ford would install a battery under the drivers seat right next to the fuses when it could be a risk? If the batteries are sealed types without any provision for venting I presume they dont pose quite the same risk as vented types?

Jon


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## Boff (May 10, 2005)

Kev_n_Liz said:


> ... the tube is an overflow for expanding acid so as not to damage the battery tray etc ...


That is not correct. If the battery is correctly filled with acid, then the acid can never expand that much that it would reach the venting tube.

In a wet battery gassing can never be completely avoided, even during a proper charge regime. (That is why you sometimes have to refill water.) The main purpose of the vent hole is to avoid a pressure build-up inside the battery. Such a pressure build-up could make the battery explode otherwise. And to avoid letting the explosive mixture of hydrogen and oxygen blow off into the habitation area, a pipe should be attached to the hole to lead the gas outside.

In case of overcharge, the vent pipe also acts as a "safety valve"

So-called maintenance free wet batteries as well as all gel and AGM batteries have built-in catalysts that let the amounts of hydrogen and oxygen from regular charging recombine "silently", without a bang. And to avoid overpressure in case of an overcharge they also have a proper safety valve.

Best Regards,
Gerhard


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## listerdiesel (Aug 3, 2012)

Boff said:


> So-called maintenance free wet batteries as well as all gel and AGM batteries have built-in catalysts that let the amounts of hydrogen and oxygen from regular charging recombine "silently", without a bang. And to avoid overpressure in case of an overcharge they also have a proper safety valve.
> 
> Best Regards,
> Gerhard


No catalyst, Gerhard, there is a natural gas recombination process going on inside the cells.

Gas production is the result of charging past its full capacity, the excess power going into the battery breaks the electrolyte down into Oxygen and Hydrogen and heat.

It is also safe only up to a degree of overcharging, once you exceed that. the safety vents will open and vent Oxygen & Hydrogen out of the cell, which effectively is water broken down into its constituent parts, so the electrolyte loses some of its volume.

Peter


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## stevegos (Jun 23, 2013)

I moved my hab battery to inside the van last year as new battery was bigger than old one. I bought some aquarium air tube and L fittings and made a vent for the battery going outside the van. The aquarium fittings fitted perfectly in the vents on the battery.

It would probably never be an issue but for a couple of ££ I feel safer!


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## Pudsey_Bear (Sep 25, 2008)

Battery storage, charging and usage is very much a black art even today, you can search for something and get very different answers, even from so called experts.


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## spykal (May 9, 2005)

I am not sure that we should be getting into a discussion over catalytic recombination in a thread asking a simple question about siting a leisure battery ....rather we should be saying to Jon make sure the batteries are fixed securely and that they do have a vent tube fitted.

Having said that... it is an interesting subject that has intrigued me for years, so Peter and Boff .. it is possible that you are both correct?

It seems that some batteries do use catalysts to recombine the gasses. My chemistry is OK but it was a long time ago :smile2:. I know that to combine hydrogen and oxygen to make water, you basically have to mix the gases together and light them. The problem is that this creates an explosion. So just mixing the gases together isn't enough - you have to do something to get the chemical reaction started. A catalyst is one way that battery manufactures have used but reading what Peter says "there is a natural gas recombination process going on inside the cells" I am betting there must be another way. Queue for another thread I think


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## listerdiesel (Aug 3, 2012)

Hoppecke manufacture catalytic gas recombination fillers, we use them on industrial standby battery sets, but no such device is fitted to any consumer batteries that I am aware of.



















While they could be used if they could be adapted to the battery fillers in some way, they are about £20 a pop so not cheap.

Gas recombination takes place under slight internal pressure, which is why Lead-Acid VRLA batteries are sealed. There is no free electrolyte to come out, it is purely to maintain the conditions for recombination.

Peter


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## Boff (May 10, 2005)

listerdiesel said:


> No catalyst, Gerhard, there is a natural gas recombination process going on inside the cells.


I think that at least in wet maintenance-free batteries a catalyst must be present, because the natural recombination is not fast enough. But I could be wrong here.



listerdiesel said:


> Gas production is the result of charging past its full capacity, the excess power going into the battery breaks the electrolyte down into Oxygen and Hydrogen and heat.


Not only. Under the conditions in a normal wet battery, breakdown of water starts at about 2.4 volts. As we have six cells in series in an ordinary 12 v battery, this corresponds to a charging voltage of about 14.4 volts. A value that is usually exceeded towards the end of a wet-type charging cycle. With wet batteries this is even deliberately done to avoid acid stratification. (The rising gas bubbles stir the acid.)

Best Regards,
Gerhard


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## listerdiesel (Aug 3, 2012)

Wet batteries float at 13.80V, sealed can float higher, but in most applications for both types, 14.40V is either a boost charge or bulk charge, neither are suitable for long-term use, only as part of a multi-cycle charging process.

Our solar controllers go up to 14.20V but drop back to 13.60V on float.

For most users, they will rarely see 14.40V for any length of time with the possible exception of a car battery.

Recombination is a slow process, but it always was, you can't speed it up without adding the catalytic converters. For most users it is entirely a background process.

Those batteries in the picture are 200AH wet vented types on a float charge, they took three weeks to build up the water globules in the recombination units.

Peter


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## mgdavid (Nov 27, 2014)

spykal said:


> I am not sure that we should be getting into a discussion over catalytic recombination in a thread asking a simple question about siting a leisure battery .......


Oh I disagree (sorry). It's all good knowledge about how things work. Knowledge is power, and helps stop one being bullsh1tted by some so-called expert* down the line.

* who works for a supplier and is trying to get one to spend money unnecessarily!


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## spykal (May 9, 2005)

spykal said:


> I am not sure that we should be getting into a discussion over catalytic recombination in a thread asking a simple question about siting a leisure battery ....rather we should be saying to Jon make sure the batteries are fixed securely and that they do have a vent tube fitted.
> 
> Having said that... it is an interesting subject that has intrigued me for years, so Peter and Boff .. it is possible that you are both correct?
> 
> It seems that some batteries do use catalysts to recombine the gasses. My chemistry is OK but it was a long time ago :smile2:. I know that to combine hydrogen and oxygen to make water, you basically have to mix the gases together and light them. The problem is that this creates an explosion. So just mixing the gases together isn't enough - you have to do something to get the chemical reaction started. A catalyst is one way that battery manufactures have used but reading what Peter says "there is a natural gas recombination process going on inside the cells" I am betting there must be another way. Queue for another thread I think





mgdavid said:


> spykal said:
> 
> 
> > I am not sure that we should be getting into a discussion over catalytic recombination in a thread asking a simple question about siting a leisure battery..
> ...


and that is why I went on to post my thoughts and question. So if you read all that I wrote .... we don't disagree at all do we :wink2:


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## trek (May 1, 2005)

Interestingly Rolls batteries sell a replacement "recombination cap". To replace the standard ones

Details here Rolls Hydro caps on sale at Bardens

Rolls Hydrocaps are able to catalytically recombine the hydrogen and oxygen gasses into pure water that returns to the battery cell. This drastically reduces the amount of "topping up" and virtually eliminates the danger of a hydrogen gas explosion.


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## trek (May 1, 2005)

Funny - but somehow I have a frown on my previous reply. Got there by mistake.


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## jspencer (Feb 27, 2015)

Hi everyone, 

Again thanks for the replies to my original post. I have looked at my batteries again and the starting battery is thankfully vented but the new house battery isn't vented and I cannot see anyway to do so as there doesn't appear to be a way to attach a tube. The battery is a good quality one from Hella (Endurant Cycle Master) but their site doesn't include instructions for specific batteries. 
I now think that relocating the battery into a battery box just above the existing battery compartment which is unused space and then venting this out of the van is probably the best idea. It seems a bit of a half arsed installation anyway with the odd bit of wood holding the battery in place!

Thanks everyone, it's better to be safe than blown up.

I'll come back and show what I have done when it's finished.


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## Pudsey_Bear (Sep 25, 2008)

You might need something like this 

Or this

Or maybe this


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## Boff (May 10, 2005)

jspencer said:


> The battery is a good quality one from Hella (Endurant Cycle Master) but their site doesn't include instructions for specific batteries.


The Endurant Cycle Master is a sealed battery. It does not require a venting pipe. There is no problem installing it in the habitation area.

Best Regards,
Gerhard


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## onnilucky (May 21, 2013)

Imagine about a fourty berth unit with sleeping accomodation on top of the 400 batteries! If you didn't sleep there it was with the torpedoes.
I wonder how all those submariners survived amongst all the Hydrogen and acid?


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## Pudsey_Bear (Sep 25, 2008)

Must have had one **** of a alternator > >


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## Pudsey_Bear (Sep 25, 2008)

HOW come we can't say H E L L again, but ******** is okay :roll:

********
ˈbɒləks/Submit
nounBRITISHvulgar slang
1.
the testicles.
2.
nonsense; rubbish (used to express contempt or disagreement, or as an exclamation of annoyance).


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## listerdiesel (Aug 3, 2012)

onnilucky said:


> I wonder how all those submariners survived amongst all the Hydrogen and acid?


They had guys who sole job was looking after the batteries and were trained to use a hydrometer.

Peter


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## onnilucky (May 21, 2013)

There was no alternators as they make AC, no good for charging batteries. They had generators which made DC, brilliant for battery charging


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## Pudsey_Bear (Sep 25, 2008)

Err twas a joke


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