Hydrogen Sulphide Smell

[kje1977]

Hi all

My RV is a Ford Monarch SE and has developed a hydrogen sulphide (rotten egg) smell in the cab but only when driving. I was wandering if someone could help with potential diagnosis, with info as follows.

1) There is nothing in the water system or toilets and in any case, it only smells when driving.
2) The catalytic converter is still on and there are no smells on the exhaust outlet.

From these suspected batteries, so following info is also important

House batteries

1) House batteries are charged by solar and engine when running. There are in 2 x banks of 2 ( eg. 2 x 6.5V = 13V but 2 banks to provide amp hours)
2) On inspection, some had lost liquid level so I topped up with distilled water - the problem still happened
3) Used a multi meter and voltages ok when engine on and off
4) No evidence of battery overheating etc.

Engine battery

1) Relatively low voltage at 12.2 - I usually leave this unhooked as I suspect a drain somewhere.
2) When engine on, multi meter reads 14.1 - 14.5V across the battery terminals
3) After running idle for 30 mins, battery charged to 12.8V. Battery not hot and electrolyte present.
4) No smells from idling for 30 mins but does smell after driving the RV for 15 mins. Smells come when accelerating

I'm at a loss other than an exhaust manifold leak before the catalytic converter, but haven't checked this

Any ideas or contacts over who to see? (I'm in UK).

Many thanks

Kris

 

[Buly]

Sounds like you are overcharging (cooking) the batteries? I have seen it before on a boat, with failed voltage regulator.
After driving for a while stop, and with your hand check the temperature of each battery. Do you notice any or all of them excessively hot to the touch? Very hot battery is most likely overcharged or shorted internally.

 

[kje1977]

Sounds like you are overcharging (cooking) the batteries? I have seen it before on a boat, with failed voltage regulator.
After driving for a while stop, and with your hand check the temperature of each battery. Do you notice any or all of them excessively hot to the touch? Very hot battery is most likely overcharged or shorted internally.

Thought this but shouldn't it show a higher voltage that I'm reading across the battery terminals when the engine is running?

Anyway, will recheck - thanks

 

[AbdRahim]

I had this smell when one battery had a bad cell. Checked by dealer with hydrometer. Once the bad battery was replaced, the odor was gone.

 

[Ernie Ekberg]

Are the batteries bulging in the middle

 

[Neal]

Sanitize your fresh water tank and see if that resolves it. Empty or not, it can stink.

 

[kje1977]

Thanks all for the help here - really appreciated.

No bulging or evidence of warming. Some updated information though.

Batteries are 6V in series and parallel to create 2 x banks of 13V. Total system reads fine at >13V.

I have just done hydrometer checks on the batteries and all fine apart from 1 cell which didn't have sufficient liquid in to draw anything into the hydrometer. This is the last battery in the series, the end cell at the positive terminal which then supplies the van. I've topped up with distilled water and left on charge via solar system

Unfortunately, I couldn't undo the cap for the last cell at the negative end to test it.

If 1 cell is dry but everything else is ok then

a) is this recoverable
b) would replacing the single battery change this or
c) could it be an overcharge issue from the alternator / voltage regulator and if so, why would this not affect other cells?

 

[AbdRahim]

How old are these batteries? Mine were only two years old and only one battery had one bad cell. Remember a weak battery in a bank will stress the other batteries. If after charging, the cell tests bad, I would replace the battery. If you cannot check the last cell, I would lean towards replacing the battery. I replace all of the batteries at 5-6 years, just as aprecaution. I don’t want a failure on the road.

 

[kje1977]

How old are these batteries? Mine were only two years old and only one battery had one bad cell. Remember a weak battery in a bank will stress the other batteries. If after charging, the cell tests bad, I would replace the battery. If you cannot check the last cell, I would lean towards replacing the battery. I replace all of the batteries at 5-6 years, just as aprecaution. I don’t want a failure on the road.

Will do, thanks

To drive this to places in the interim, can the leisure batteries be isolated / disconnected and the RV driven?

I have an isolator switch on the positive terminal outlet

 

[AbdRahim]

Probably can, but then you would have nothing working in the house,m lights, refrigerator(DC), etc. I would get this rectified immediately. Also, the fumes are not healthy to breath. Also, as long as the bad battery (assuming there is only one) is connected to the others, it will draw them down. Check the charging system to insure you are not overcharging. I would have them all checked and replaced, as necessary.

Hopefully, these are not the original batteries. If so, replace them all.