# [EVDL] Carbon monoxide detectors and charging



## EVDL List (Jul 27, 2007)

Slightly off topic but possibly pertinent to EV's.

This AM the carbon monoxide detector in my house went off. Coincidentally
(or maybe not) the charger did not shut off overnight and the batteries
(flooded lead acid) had a lot of gassing.

I realize that carbon monoxide is not a byproduct of charging. I have my
suspicions why the detector went off (unrelated to EV's).

My question is can the carbon monoxide detectors be fooled by the gasses
produced with excessive battery charging?

Barry Oppenheim
New Hope, PA
www.JustAnotherEVConversion.blogspot.com

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## EVDL List (Jul 27, 2007)

My carbon monoxide detector will go off by opening a can of alcohol in the 
same room its in. Also some floor cleaners has set it off. Now when I cook 
my Montana 50 below powerful chili, it also fire off.

So the battery venting of H2O2 plus some of the minute arcing from the 
battery to a conductive ground path. I could not see this arcing when the 
lights where on, but I could see it with the lights off. This cause very 
small black burn spots.

This is why I remade all my battery boxes in a non-conductive material and 
make sure the batteries are at least space about 1/2 inch away from the 
surface of the battery box.

Roland


----- Original Message ----- 
From: "Barry Oppenheim" <[email protected]>
To: "EVDL" <[email protected]>
Sent: Thursday, May 14, 2009 6:09 AM
Subject: [EVDL] Carbon monoxide detectors and charging


> Slightly off topic but possibly pertinent to EV's.
>
> This AM the carbon monoxide detector in my house went off. Coincidentally
> (or maybe not) the charger did not shut off overnight and the batteries
> (flooded lead acid) had a lot of gassing.
>
> I realize that carbon monoxide is not a byproduct of charging. I have my
> suspicions why the detector went off (unrelated to EV's).
>
> My question is can the carbon monoxide detectors be fooled by the gasses
> produced with excessive battery charging?
>
> Barry Oppenheim
> New Hope, PA
> www.JustAnotherEVConversion.blogspot.com
>
> _______________________________________________
> General EVDL support: http://evdl.org/help/
> Usage guidelines: http://evdl.org/help/index.html#conv
> Archives: http://evdl.org/archive/
> Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev
>
> 

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## EVDL List (Jul 27, 2007)

Barry -

The CO detector in my garage goes off when I charge, too. I consulted the
oracle (Wikipedia) who mentioned that some CO detectors are... 

[a] type of fuel cell that instead of being designed to produce power, is
designed to produce a current that is precisely related to the amount of the
target gas (in this case carbon monoxide) in the atmosphere. Measurement of
the current gives a measure of the concentration of carbon monoxide in the
atmosphere. Essentially the electrochemical cell consists of a container, 2
electrodes, connection wires and an electrolyte - typically sulfuric acid.

I suppose that the H2S from the battery outgassing is combining with water
vapor to make H2S04.

MRO





> Barry Oppenheim wrote:
> >
> > Slightly off topic but possibly pertinent to EV's.
> >
> ...


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## EVDL List (Jul 27, 2007)

We've had a couple of EVDL threads on this in previous years. I couldn't 
find the one I was thinking of, but in 2001 we had this exchange :

> I heard from Bob Wheeler that somebody was charging their EV pack in
> the garage and the hydrogen gas it generated actually set the carbon
> monoxide alarm detector off.

Lee Hart replied :

> I doubt it was the hydrogen. More likely, it was suspended sulfuric
> acid mist in the air. 

> There are gas detectors for hydrogen, but carbon monoxide detectors
> aren't likely to do it. 

In September of 2002 Rod Hower posted this :

> At 1 this morning the CO detector downstairs sent off a warning, it was
> at 100. The CO detector upstairs read 34. My wife called the fire
> department who came out and read 30 down stairs after the doors where
> open. We went in the garage and he read 150 max. What was in the
> garage? The TEVan that topped off on a long charge with batteries
> bubbling for a while. 

Later Rod reposted :

> I found this on the web. The most common problem gas is hydrogen,
> which interferes with carbon monoxide. A method to reduce this cross
> sensitivity is to use a second sensing electrode underneath the first
> sensing electrode. The first sensing electrode responds to both carbon
> monoxide and hydrogen while the second sensing electrode responds only
> to the excess hydrogen that has gone past the first sensing electrode. 

It's unclear to me exactly what his second post means. They may be talking 
about ways to PREVENT false triggering on H2. (Rod gave a source for this 
but it's apparently no longer available on the web.) 

In any case, it does appear that something about battery charging can 
trigger CO detectors.

Might be worth further investigation.

David Roden - Akron, Ohio, USA
EVDL Administrator

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## EVDL List (Jul 27, 2007)

> EVDL Administrator <[email protected]>wrote:
> 
> >
> > In any case, it does appear that something about battery charging can
> ...


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## EVDL List (Jul 27, 2007)

> [email protected] wrote:
> > I would also like to not that the fireman's CO detector sensor went off the charts when he placed it near the exhaust of the battery blower fans.
> > (This was on a Dodge TEVan with 30 SAFT STM-180 NiCd batteries which gas quite a bit on charge)
> 
> ...


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