My CO alarm woke me up.

[Jaydug]

I've extracted this paragraph from my blog since it may be of interest to others. I was staying in Salamanca for three nights.

"In the early hours of Wednesday morning my CO detector woke me. My gas bottle was turned off so assuming the detector was faulty, I removed the battery. Next morning I replaced the battery but 30 minutes later the beeping started again. I took the battery out again. Later in the day I noticed in the caravan an unpleasant smell. I began looking for a likely cause in cupboards; behind the fire; in the wardrobe and finally under bed lockers. That's where the smell was strongest. I went outside to look in the battery box and found the battery was so hot, it was impossible to touch it. I disconnected the positive terminal and left the battery to cool. Later I put the meter across the terminals. It read 10.8 volts. The battery had suddenly died. Just a short while later I replaced the battery in the CO detector. No more beeping! Obviously the detector recognizes more than carbon monoxide. When I left home on Sunday I used the mover to shift the van from the garden on to the front drive. Quite a bit of manoeuvring. The battery seemed in excellent health then. But now I desperately needed a new battery. Before moving on to my next camp site I went to Carrefour in Salamanca. I couldn't find a leisure battery so instead I bought a 90AH diesel starter battery".

 

[Spurtle]

In this last year I have dealt with at least four situations that mirror your story....

In two cases the owners investigations led them to the source of the problem being an overcharging battery, in the other two, a simple instruction to check the temperature of the battery indicated the same issue ( I would add that the request to check the battery temperature included the instructions for them to only do so after switching off 230 & 12v supplies and ventialting the battery box and the inside of the motorhome/caravan..... prior to vacating it for a couple of hours ) ...even after that time it is easy to detect that the battery is much hotter than it should be.

As you say, there is obviously something about CO detectors that causes them to be triggered , or at least 'chirp', by something other than carbon monoxide... In this case it is Hydrogen Suphide....

It is produced when electrolyte levels drop in the battery cells to the point where the lead plates become exposed.
Hydrogen , produced as part of the charging process , reacts with sulphates on the exposed lead, producing Hydrogen Sulphide ...... damn awful stuff..

It's corrosive, highly flammable and poisonous too...... in the world of sparky sparky bang bang gases...it's particularly nasty... Hydrogen makes propoane and butane look positvely friendly, in explosive terms.
Both the 'lpg' gases have to be within relatively narrow limts of gas/air ratios to burn ...not so Hydrogen.
It was responsible for blowing the top off the Fukushima reactor.

Fortunately only one of the siutations I have been invloved in resulted in a battery explosion, and that was in a UK built motorhome with the battery installed in a centrally mounted well in the floor.. Unfortunately the manfacturer had chosen to site the main battery fuse in the same box...equally unfortunately , someone charged with the task of fitting a new battery at some point had managed to do reasonably well, apart from trapping the vent pipe under the battery, preventing the escape of hydrogen to the outside of the vehicle...until it was released into the box when the pressure caused the vent pipe to blow off the battery .

So always check that elctrolyte levels in batteries are as they should be and that vent tubes , if required, are fitted properly..or even fiited at all.
Keep an eye on battery voltages under charging and rest conditions....and any tendencies for the charge level to drop while at rest.

If you have access to a battery 'shunt' type tester , use it... and , if you smell rotten eggs ., or your CO alarm 'chirps' or sounds, even with the lpg system isolated ..be suspicious..

 

[Jaydug]

Thanks for that. When I found the battery was hot, the first thing I did was to check the electrolyte levels. Surprisingly they were ok. Since fitting the new battery I've opened the box several times and checked the temperature with an infrared thermometer. It's showing very little more than ambient.

 

[Gafferbill]

........well done that CO alarm

Saved you from a possibly dangerous explosive situation.
I once had a Truck battery explode when a spark from a loose battery terminal ignited the Hydrogen.
Acid and bits of battery case flew over a wide area hmy:

 

[aldo]

This happened to me last summer, virtually word-for-word as described above.

You have to ask ... if these chargers are as "smart" as the manufacturers claim, why aren't they clever enough to detect that they're suddenly pushing large amounts of charge into a battery that's obviously in trouble?

 

[bertieboy1]

What is battery temperature,the outside casing temperature ?,the electrolyte temperature ?.The only temperature you can measure with sealed cells is the outside casing temperature,is this what the battery manufacturers use to determine battery temperature.
What is hot and what is not hot,from experience if you can't touch it it's too hot.

 

[chrisn7]

What is battery temperature,the outside casing temperature ?,the electrolyte temperature ?.The only temperature you can measure with sealed cells is the outside casing temperature,is this what the battery manufacturers use to determine battery temperature.
What is hot and what is not hot,from experience if you can't touch it it's too hot.

This is a question I have just asked myself. Changed the van 3 weeks ago and went straight off in it to check everything working. Now the battery was getting on a bit and I had topped up all the cells, but I noticed that if the charger was switched off, the battery was losing charge far too quickly. On checking the battery it was very hot - and gassing off furiously -a combination I have never seen on any car or leisure battery. I'm guessing the new van charger puts out the full 14.4 volts, whereas the old one was limited to something less, and this was enough to finish off the old battery. No problems since with it replacement

 

[bertieboy1]

My experience of industrial batteries is that when manufacturers talk about battery temperature they mean electrolyte temperature.
You don't say if the battery was on charge or not when experiencing hotness and gassing off.This can happen during high discharge as well as during charging.The battery will gas off when overcharged.
From your description the battery has lost it's charge retention capability - nothing you can do will recover this and as you say a new battery is the answer.

 

[Raywood]

We did have a problem with the battery overheating some years ago. It was in a sealed box so no fumes seemed to have entered the caravan, we just became aware of the box becoming very hot and disconnected the battery. If the box was sealed not sure how the CO2 detector picked up the problem.

 

[rosies]

Its good to know that a CO alarm has more than one emergency safety feature , another potential life saver . I only hope many caravanners read this item and avail themselves of the information and purchase a CO alarm and smoke alarm ( if none fitted ) for their family safety .

 

[Jaydug]

If the box was sealed not sure how the CO2 detector picked up the problem.

It can't be sealed when there are grommets and wires coming through the back of the box?

 

[ProfJohnL]

I am not surprised that a CO detector will actually respond to other gasses. Its very difficult to make any detector only respond to one specific trigger, they usually have some response to a range of different materials. It is however useful that the detectors in discussion have actually responded to the battery gasses, though just because some designed have that sensitivity, you cannot assume that all CO detectors will respond in the same way. It still pays to check your battery manually.

In terms of what constitutes a 'room seal', there is no such thing as an absolute seal, and where appliances have to be 'room sealed' the standards set limits on the volume of transfer. Please don't be alarmed by that revelation, the permitted amounts are very small and in the context of a properly ventilated caravan pose no credible risk.

 

[Jaydug]

In terms of what constitutes a 'room seal', there is no such thing as an absolute seal,.

The CO detector 'smelt' the hydrogen gas nearly 24 hours before my nose did. Whether that's down to a sensitive detector or my depressed olfactory system, I wouldn't know.... hmy:

 

[JTQ]

The battery ageing is most likely to have shed enough paste that one cell shorts out at its base. Then instead of being a "12" volt battery its only a "10" volt one though the charger still thinks otherwise so is way over charging those 5 viable cells . Hence the heating and break up.

 

[Gafferbill]

A lead acid battery is supposed to ventilate to the outside so I have removed the battery box door seal on my caravan.
What is it fitted for?
Removal has improved ventilation with no detrimental problems.

 

[bertieboy1]

We have found these detectors are affected by ambient temperature variations,going off when nothing is on and no cooking (usually when the caravan door is opened)

 

[carolpalmer]

Check for the control panel fault log for indications. Also check for the location and environment of the sensors, and that the PIR's are not placed above the radiator. Ensure the devices are firmly placed and screw mount door magnetic contacts than using sticky pads. For more technical know-how take expert advise from residential alarm systems who might help you in fixing this problem.

 

[WoodlandsCamper]

Check for the control panel fault log for indications. Also check for the location and environment of the sensors, and that the PIR's are not placed above the radiator. Ensure the devices are firmly placed and screw mount door magnetic contacts than using sticky pads. For more technical know-how take expert advise from residential alarm systems who might help you in fixing this problem.

We are in the UK talking about touring caravans. They probably have different regulations in Canada for domestic alarms.

 

[Pauljw]

Slight thread drift , but a friend who was in the Royal Navy onboard a RN ship told Me a story of 2 Seaking helicopters within the hanger onboard . They had just shut the hanger door and there was a huge explosion , rupturing the hanger door and writing off one of the Sea King helicopters. At the board of enquiere it was caused by ( Thermal Shock ) something to do with the batteries on the helicopter, Now , without wanting to distress or worry anyone , could that happen in a Caravan ?

Paul

 

[Damian]

Given the right circumstances any battery can explode.
It has happened to caravans , whilst on charge on the bench and in situ in the van but is not a common happening.

The best thing to do is regularly check the battery to feel if it is getting hot, not every 5 minutes, but every now and then.
Keep the terminals clean and make sure the electrolyte level is correct.

 

[ProfJohnL]

I looked up battery explosion,and most articles referred to lithium-ion batteries the type often used in laptops, with references to thermal runaway etc.

I refined my search lead acid battery explosions, with far fewer results, but there are circumstances where Lead Acid batteries can become explosive, and these usually relate to final stages of charging. Non of teh articles I saw mentioned caravans, so I conclude the issue is very rare for caravanners.

However I found one particular article:--
http://www.yachtingmonthly.com/archive/how-batteries-can-explode-and-how-to-avoid-it-3930

which may be interesting to some readers.

 

[Raywood]

Batteries can explode. I think though it is only when they are being charged but in a caravan on a hook up this is most of the time. I do remember one of my colleagues at work having a battery explode while they were charging it in the living room. That idea is not recommended but as they had a flat there was nowhere outside the living area to do it.

 

[Pauljw]

I shall check My battery now and then Damien in the future and Prof John that was an interesting article .

Paul

 

[Jaydug]

Batteries can explode. I think though it is only when they are being charged.

Yes - I agree with you. It's nearly 10 months ago that I started this topic. Just to reiterate - my battery must have been healthy on that Sunday afternoon last November because it moved my van some distance on the mover before I left home. The caravan sat on the ferry Sunday & Monday night and (presumably) started on-tow charging on Tuesday morning. I arrived in Salamanca that same evening and plugged into the mains. It was about 10 hours later that the CO detector sounded. By 4pm in the afternoon the battery terminals were too hot to touch with the voltage only showing 10volts. My guess is that the battery wouldn't have waited long before exploding.