Rotten eggs and red hot batteries

[Andymac0143]

Hey everyone. I have a problem (not a medical one relating to my bowels before anyone says)

On the way home we had the rotten egg smell and red hot main and leisure battery issue...

In summary:
1972 Westy with 1700cc engine.
Main battery with smart charging system to a leisure battery (main battery approx 1 year old) leisure battery unknown age, but has been fine until now.
Leisure battery also hooked to a battery charger that kicks in when we're on mains hook up a ctek mxs 5.0 charger.

All has been fine until recently I've had a few wiring gremlins and shorts etc.. Creeping in and a local garage who I know and trust have sorted an awful lot out for me. They recently spent time sorting bad earths in the engine bay and also issues around coil wiring, but as with all vans I've inherited many previous owners and probably garages fixes and 'tweaks' so it looks like a London Underground map under the dash tbh.

This is the first time this has happened and we've been on mains and used the charger numerous times... However I need to check the charger hasn't switched mode (don't know if this could cause it) since it only happened on the journey home not while camping.

Can anyone recommend the best approach for fault finding and an order to do it in to find the cause... I've read a load of horror stories of how the batteries can explode and catch fire etc.. So have made myself rather nervous about starting the engine etc.. But hopefully someone can put my mind at rest and dispel the myths from the facts.

I have 2/3 weeks until we're due to go away again but I'd like to have a go (only way you learn) with my trusty multimeter and not just take it to the garage.

If I've not given enough info please let me know.

Thanks in advance for any help.

 

[Dickie524]

Hmm, they are probably related as rotten egg smell is Sulphur-related and battery acid is sulphuric acid...

But wiring wise, none the wiser, sounds like its overcharging maybe? But I haven't done any wiring on these, sure someone will be along in a minute who has though...

 

[rlepecha]

First check for me would be the output from the alternator.

Start the bus and connect a multimeter to the positive pole on the starter battery and the other to ground, bring the revs up to around 2000rpm and see what the output is.

It should read something less than 14.5v but more than 13.8v.

Sounds like overcharging which is in turn boiling the battery acid, so if that reading is over 15v its likely the alternator is broken or its regulator is broken(some are replaceable I think)

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[Bluesnailman]

historically I've messed around with charging systems, earths etc only to discover the battery was the problem. You're smelling sulphur (rotten eggs) so id check out battery condition, either acid level or its ability to hold a charge before going too far with anything else.

local battery and tyre fitter should of the check for free

 

[Andymac0143]

Thanks Guys.

My first gut feel was faulty battery (Main battery), however given its only a year old and it seems to be overheating the leisure battery too (which is connected via the smart charge system) I'm pondering the overcharging potential of the alternator / generator... being the culpret.

I will fire up the engine and test the output of the generator this evening first to rule that out as its the quickest to test then I'll remove the two batteries for testing if it's not the generator.

Any other ideas for potential causes keep them coming...

thanks

 

[matt-me]

I'd put this kind of question on VZI so Speedy Jim might pick it up. He's the leccy expert.....

 

[KateLovesPurple]

I'd agree with the alternator overcharging due to a regulator failure. If both batteries are getting hot whilst driving, there is little else it can be.

 

[Andymac0143]

What's the easiest way to test whether it's the regulator itself or the alternator? reason being regulator = ~£20 (guessing) and alternator over £100 I bet...

 

[Peter Good]

You have the answer to the first question in the posting by rlepecha earlier today.....
As for the alternator it is very dependent on the exact part number as to whether the regulator can be replaced.
Original ones had an external regulator, but the alternator itself was pretty rubbish so I doubt many have survived.
PG

 

[rlepecha]

Sorry Andy, to clarify my previous post if the alternator itself was broken its likely there would be no output whatsoever. Ultimately its 3 windings(I Think) that are producing an AC output that is rectified and regulated to 14.4v DC, usually the windings don't go wrong but the regulators do! If the regulator isn't replaceable its the whole lot you would need to change, hence my comment about a broken alternator.

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