Exploding Battery!

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murph
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I bought a 1985 300GD swb yesterday down in Plymouth and the seller and his wife could not have been more hospitable (an old club member) with loads of coffe and bacon butties!

The Gee has had a lot of recent work not least of all a new alternator and battery.

On the 165mile homeward journey - BANG- the sealed battery blew.

The AA man was called and removed the very hot battery and fitted a tempoary one and tested the alternator charging - it was putting 19amps into the battery very high I understand.

Can anyone tell me the correct amount of amps it should be charging at?

What referance numbers would be on the alternator as the owner seems to think it is genuine Merc (cost £276 plus vat) and I am not convinced although the breather is attached ?

The battery was a 12v 80amp, the manual says it should be 88 does this make a huge differance? what battery make and type should be fitted?

Is the solution simply a new alternator and battery or do I need to check anything else?

I will be having an interesting chat with the garage who installed this on Monday

Thanks for your help
Murph
PS anyone got an alternator?

Russ280
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Exploding Battery

80 or 88 amp battery won't make much difference, just refers to the capacity.
Don't jump to the concluesion its the alternator. It sounds more like the regulator, which as the name suggests regulates the charging current to the battery. This can be replaced as a separate item.

murph
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Exploding Battery!

Thanks for the reply Russ

Where would I find the regulator and how would I check to see if it is working OK?
Is this an expensive part?
Many thanks
Murph

Greeney
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Joined: 04.11.2003
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I agree

about the regulator box and you should be able to get one from MB main dealer not sure of the price but if it comes to an alternator renew I know of a company here in Dover that will do a complete rebuild to a new standard for a maximum of £50 sometimes cheaper. I have had a couple done over the years and they are very good. even sandblasted and painted to look new

whelanrob
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amps or volts

are you sure the aa man said amps or could it have been volts.
While working at my engine the other night I shut it down to hear that there was a fizzing sound coming from the battery.I started up again and checked the voltage ,itwas 14 volts but would go up to 18 volts with some revs.I got a new regulator from the local Bosch agent for 20 euros and fitted it,now the voltage is 13 to 14 volts irrespective of engine speed ,as it should be.
The current flowing to the battery is highest after startup,so as to replenish the lost charge ,dwindling to a small charging current after a time ,this is so long as the alternator has the reserve to power the lights and other auxillaries,if not ,these must also draw from the battery.I fitted a 70A alternator out of an old Saab 900('84),in place of the standard 55A G-wagon one,a direct replacement for the original,so if you are stuck for one see if the scrapman has any Saabs,more likely than G wagens,thats if the regulator does'nt fix it.
bob

murph
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Thanks guys

Bob
I think you were correct and it was volts not amps, my confusion!

Thanks for the advise I will replace the regulator and get a new battery and try that first.

The saab alternator sounds a useful upgrade so if I need one I shall go this route as I am sure it will be less expensive.

Many thanks again
Murph

murph
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Latest news !

Hi All

Well today we had confirmed that the new regulator was not going to get us back on the road as we are still pushing out 18 volts!

The Gee is now at Mercedes and we think that possibly the new alternator fitted is a 24 volt and not 12volt??? anyway they are going to look at it within the next day or two and get us back on the road.

I will keep you posted

Cheers all
Murph

g man
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Exploding Battery!

the alternator on the 460 Gs are the same as 307d van as are most parts? :shock:
peter

murph
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The saga goes on!!!!

Well last week Mercedes could not find a fault with the alternator even though the AA and RAC had been out and confirmed 18-19volts being poured in???

I took the car back and after a few days and not many miles - yes you guessed it the alternator has now gone so back to the dealers.

I will give you an update when I have one.

I bought the G to use and so far not too much of that. I live in hope.

Murph