CO Problem

[PaulHull]

Have spent the last week de-winterising the caravan (including patching a gaping hole in the roof!) and are planning on going away this weekend.

I've also installed a CO detector which after installing yesterday has been going off during the night. This puzzles me because the only things that are currently on in the caravan are electrical i.e. the battery is charging and the fridge is on. That is it. The gas bottle is still in the shed!

Can anyone think of anything else that might have caused the alarm to go off? I don't know at what time it activated but when I got up for work at 5 it was beeping away. I reset it and put it back up and it hasn't gone off again which makes it weirder! Surely CO would build up and up?

 

[Damian]

It sounds like a faulty detector.

Try it away from the van or take it back and change it .

 

[PaulHull]

I'm going to get another one and put it up in the van alongside the current one - if the new one goes off with the old(er) one then I know I have a very weird (and quite worrying) problem!

 

[antrimboy]

Low battery?????

 

[PaulHull]

It's a brand new detector - literally had brand new batteries fitted last night - perplexing!

 

[Royston]

It sounds faulty to me the co alarm that i have installed in my house when you press the test button the noise that it gives out is horendous, noway could you listen to that more than once.

Royston

 

[PaulHull]

Well I've bought a second one and both are in the van (and have been for five hours) and not a peep out of either of them! The van has been left all day as it was last night (i.e. battery charging, fridge on) so you'd think that the concentration of CO would have increased as the day went on but apparently now is all well.

I'll have to see what tonight brings (hopefully nothing - the new one is louder than Keith Moon and won't please the neighbours if it does go off!) All I can conclude is that the first one is either faulty of that one of the many factories around the docks are releasing things into the air that they shouldn't (which wouldn't even remotely surprise me!)

 

[PaulHull]

Well it turns out it's the battery. If it's left charging it sets the alarms off. If it's off, it doesn't. I've also bought a CO 'patch' which goes dark if there is CO in the air but it has gone 'light' instead indicating that it has been damaged (which according to the instructions is down to many things, none of which have been done near it) so I can only assume that the battery is giving off some kind of gas that it shouldn't (it looks like an old truck battery that came with the van) so a spanking new leisure battery is in order!

Strange (and a little scary!) how a battery can activate a CO alarm!

 

[ProfJohnL]

Hello Paul,

I am concerned that you have conclude that charging the battery is causing the detector to activate.

It is a characteristic of lead acid batteries that they can give of Hydrogen gas when they are being charged. Hydrogen gas is highly flammable and will go off with bang.

Because of this fact, batteries should be fitted in a purpose designed box that only vents and opens to the outside. If yours is fitted in such a box, then something has compromised it room seal, and it should be fixed.

 

[PaulHull]

Hi,

The battery is in a sealed box however the seal is badly perished and is going to be replaced before the van is used again. It doesn't, however, have any means of ventilating (it's in a box under the seats). Like you say hydrogen is explosive so improvements to the ventilation are in order me thinks!

 

[Sproket]

Paul,

Have you checked that the charger is not over charging....??

Min requirements for you new battery in that storage position is a sealed battery, ( preferably a gel one ) & if it comes with a vent tube, drill a hole through the floor for it to vent any gases outside the van.

 

[Chris_374413356]

I suggest if the battery is constantly venting Hydrogen to activate the CO detector then the battery charge voltage should be checked as it seems to be trying to charge a fully charged battery, and yes it must be sealed from the living space and sources of ignition.

 

[ProfJohnL]

Hello again Paul,

You have not told us what model and year of caravan you have, but from your most recent posting I have a strong suspicion that either it is a very old British caravan or possibly a continental model.

Please forgive me if I am wrong about that, but regardless of the accuracy of my suspicions, something needs to be done to improve the safety of the situation.

The battery should be vented to the outside. with some batteries there is a vent pipe connection, and all that is required is to arrange a short length of plastic hose (usually available from caravan dealers of even your local DIY store) that pushes onto the battery spigot and can be passed through a close fitting drilled hole in the floor. alternatively you get proper battery boxes that fit through the side wall of the caravan.

Particularly if the caravan was not designed with a 12V battery system in mind, I wonder what type of battery charger you use? The first chargers fitted to caravans were basically the same as a mains powered car battery charger. These are fine for short term charging, but their design did not regulate the charge current or voltage, and if left on for any length of time they would often over charge batteries and lead to the batteries gassing off. This is the likely cause of your CO detector triggering.

Since about 1984 caravans systems built in the UK had to limit their charge voltage to prevent over charging batteries. These devices are considerably more complicated than a basic charger, so much so they are now called power supplies to differentiate.

The modern units are available in a number of power outputs, and the larger models provide enough output power to run all the normal 12V equipment with out the need for a battery - provide mains power is available. All these new caravan power supplies are suitable for conction to a leisure battery.

Do not be fooled into think that 12V systems are safe because of the low voltage. Given poor installation or connections and they can have enough power to start a fire, so if you are not confident or have any doubts with electrics it is best to use a professional fitter.

 

[PaulHull]

Hi,

It's a 1992 Swift Corvette. The 12v installation is the caravans original and the the 'charger' is a KT12 Transformer / Charger. The battery (which came with the van) is a bloody huge Mercedes Benz truck battery which doesn't appear to hold its charge very well (i.e. the voltage indicator stays in the yellow after charging - it stays there for a very long time, but is never in the green unless it is connected to the mains, obviously defeating the point!). As far as I understand (and that isn't that far!) - until the battery is fully charged the transformer will continue to send power to it, and until the 'full' voltage is reached the transformer will think that the battery is not fully charged, and because the battery is mullered (apparently) it will never reach its full voltage and therefore remain on charge until it evaporates all of it's fluids?

This battery is obviously poorly (and unnecessary - it completely fills the box it's in) and I'm going to replace it with an 85 ah sealed diamond leisure battery. I don't need a big battery as the only time we would need to run on battery power is to run the telly for half an hour when we stop on long distance trips and in the event of power cuts.