Habitation Battery overheating

mike mcglynn

mike mcglynn

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St. Helens MERSEYSIDE
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Autosleeper Warwick XL
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A long time now
Hello, Can any kind person tell me why ? I have brought van home from storage after fitting new engine battery old one was dead :xangry: so I am on ehu to boost up the hab batteries with the onboard sargent unit, I have 2 x 110 amp ones which are about 3 years old and when I went into the van after about 18 hours on hook up there was a terrible pong from under the seat where the hab batts are located, one battery was cool and the other one was very hot to the touch so I have switched everything off and am waiting for things to cool down before I do anything. :xshout:
 
Turn off your charger NOW!

It sounds like an internal short circuit and the battery could explode


DO NOT use the 12v system until the battery is replaced.
 
remove and get the battery replaced. ask for compo for wasting your time and leccy as well.
 
Wildman said:
remove and get the battery replaced. ask for compo for wasting your time and leccy as well.
Click to expand...
Hi Wildman its not the new battery its an older one the new one is for the engine bay.:xThumb:

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No one has mentioned the most dangerous aspect of all this ..
PLEASE BE AWARE THE GAS GIVEN OFF IS EXTREMELY VOLATILE.. IT IS HYDROGEN !!!!

By now yours will be pretty much clear, but for anyone who gets the pong of rotten eggs please make sure the area is WELL ventilated and for goodness sake do not switch on or off anything IN the van. Disconnect the EHU lead from the opposite end to the van

I have seen the sides of building being taken out
 
Yet Zeppelins proved difficult to blow up for a VERY long time despite being full of it :xlaugh:
 
It sounds like a massive overcharge but why just one??
 
Techno100 said:
Yet Zeppelins proved difficult to blow up for a VERY long time despite being full of it :xlaugh:
Click to expand...
Dunno about the Zeps Andy.. Before my time mate LOL !!
But look at what happened to the R101 :(

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Badknee said:
It sounds like a massive overcharge but why just one??
Click to expand...
One knackered cell will drop the battery voltage even with two in parallel low enough to cause the charger to work at full output, most of that output will be converted to heat by the shorted cell thus depriving the other cells and the healthy battery from getting enough to cause a rise
 
Last time i saw an exploded battery it was on a car.

The whole top cover had blown off causing some serious denting on the bonnet and one side had blown out.
acid everywhere.

This had happened as the driver turned the key to start the engine.....must have put a severe load on an already faulty battery.
 
When we had a similar problem we blamed the dog for a while,does the gas rise or fall?should we ventilate top or bottom."I don't mean the dog"________Martin:sick:
 
Rises.. There is a bit of a hint in there .. they filled Zeps and dirigibles with the stuff :xwink:
 
Mr Ed said:
..........does the gas rise or fall?should we ventilate top or bottom."I don't mean the dog"________Martin:sick:
Click to expand...

It will most definitely FALL..

Hydrogen is a colourless, odorless, tasteless gas.. lighter than air.. small amounts can be given off during normal charging.. what you smell is Hydrogen Sulphide..

Hydrogen sulfide is the chemical compound with the formula H2S.
It is a colorless gas with the characteristic foul odor of rotten eggs; it is heavier than air, very poisonous, corrosive, flammable, and explosive.

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Last edited:
Don't attempt to disconnect the faulty battery until the motorhome has been well aired, as there's a high chance you'll get a spark.
Disconnect the EHU, then leave all windows and doors open.
 
I had a similar situation last year.
First thing I noticed was the panel showing about 3 amps charge going to the hab batteries when it should have dropped to zero.
On investigation I found one of the two hab batteries a little warm.
I turned off the charger and next day disconnected the faulty battery. Later when funds became available I replaced both on the assumption the the other probably wasn't far behind the first as both were originals fitted in 2005.

An interesting aside is that the failed battery was a second battery supplied by the dealer as the vehicle was originally fitted with only one by Rapido. It was also the furthest away one which leads me to think that there is something to the recommendation that multiple batteries should connected as show below
Parallel Battery Connection.gif
 
Jean-luc said:
I had a similar situation last year.
First thing I noticed was the panel showing about 3 amps charge going to the hab batteries when it should have dropped to zero.
On investigation I found one of the two hab batteries a little warm.
I turned off the charger and next day disconnected the faulty battery. Later when funds became available I replaced both on the assumption the the other probably wasn't far behind the first as both were originals fitted in 2005.

An interesting aside is that the failed battery was a second battery supplied by the dealer as the vehicle was originally fitted with only one by Rapido. It was also the furthest away one which leads me to think that there is something to the recommendation that multiple batteries should connected as show belowView attachment 50675
Click to expand...

Wouldn't that give you 36v
 
No, 12v.
You would have to connect the batteries in series ( + to minus on the next one and + to minus again )
All the -ves are joined as are all the +ves so 12v output
 
Jaws said:
No, 12v.
You would have to connect the batteries in series ( + to minus on the next one and + to minus again )
All the -ves are joined as are all the +ves so 12v output
Click to expand...

Ok.. I'm a novice so will read with interest.. why is there any difference between the set up suggested here and connecting all the batteries in parallel and then connecting to the system?

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Some people use cable that is really too thin to carry the current without a voltage drop.. So on anything bar a very short run you end up with an imbalance and one battery never reaching the same potential as the other.
The cure ( as such ) if you have to have the batteries mounted well apart is to use really nice thick beefy cables ( jump lead sort of size )
Might sound OTT but it will minimise losses betwixt the batteries
 
All cable has some degree of resistance to current flowing through it. It is this fact that results in batteries downstream from the one which is connected directly to the source of discharge/charge being subjected to reduced discharge/charge. It is the reduced charging which in the long term can shorten its life.
Good beefy cabling will reduce the imbalance significantly but it is only by connecting them as shown in the diagram will all the batteries be subjected to equal demand and charging.
Realistically it probably matters not a lot but as a certain retailer says 'every little helps'
 
Cannot argue with that J L..
But go to 10mm cable with a maximum current of 10 amps and I should think you would need a scope rather than a meter to detect the difference :xwink:
 
mjltigger said:
Ok.. I'm a novice so will read with interest.. why is there any difference between the set up suggested here and connecting all the batteries in parallel and then connecting to the system?
Click to expand...
In my opinion and for our useage type.....none.

If it was an emergency battery bank on constant charge with occasional load then maybe cross wired.

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It's worth saying that, provided care is taken to insulate the leads, you can remove the duff battery and simply continue to use the remaining one(s) until it is convenient to replace both (all). [Can't remember whether you have two or three!]
 
mjltigger said:
I'm a novice so will read with interest.. why is there any difference between the set up suggested here and connecting all the batteries in parallel and then connecting to the system?
Click to expand...


if you are interested to know, then more reading here on connecting multiply batteries... however..

" if you only have 2 batteries, then simply linking them together and taking the main feeds from diagonally opposite corners cannot be improved upon... "

How to correctly interconnect multiple batteries to form one larger bank.
http://www.smartgauge.co.uk/batt_con.html
 
Gassing emits Hydrogen and oxygen and as stated is very explosive.


Risk of explosion[edit]

Car battery after explosion
Excessive charging electrolyzes some of the water, emitting hydrogen and oxygen. This process is known as "gassing". Wet cells have open vents to release any gas produced, and VRLA batteries rely on valves fitted to each cell. Catalytic caps are available for flooded cells to recombine hydrogen and oxygen. A VRLA cell normally recombines any hydrogen and oxygen produced inside the cell, but malfunction or overheating may cause gas to build up. If this happens (for example, on overcharging) the valve vents the gas and normalizes the pressure, producing a characteristic acid smell. Valves can sometimes fail however, if dirt and debris accumulate, allowing pressure to build up.

Accumulated hydrogen and oxygen sometimes ignites in an internal explosion. The force can burst the plastic casing or blow the top off the battery, spraying acid and casing fragments. An explosion in one cell may ignite the combustible gas mixture in remaining cells. In a poorly ventilated area, connecting or disconnecting a closed circuit (such as a load or an operating charger) directly to the battery terminals may cause an explosion as the sparks produced ignite the gas mixtures vented from the cells.

The cell walls of VRLA batteries typically swell when the internal pressure rises. The deformation varies from cell to cell, and is greater at the ends where the walls are unsupported by other cells. Such over-pressurized batteries should be carefully isolated and discarded. Personnel working near batteries at risk for explosion should protect their eyes and exposed skin from burns due to spraying acid and fire by wearing a face shield, overalls, and gloves. Usinggoggles instead of a face shield sacrifices safety by leaving one's face exposed to acid and heat from a potential explosion.
 
Thanks to everyone for your informative and helpful replys I have ordered 2 new batts from battery megastore same spec as before and will be using the wiring that was supplied by sargent in my autotrail van so we will see how that goes and may I take this opportunity to wish all the funsters a happy new year and may all your troubles be little ones . Safe travels to one and all x:-)
 

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