Classic cars forum & vehicle restoration.

[ukdave2002]

Cranking speed on the MGA has slowed down in recent months; it has a pair of 6v batteries that sit under the car just forward of the rear axle, so not visible without removing a cover. I thought I may have to clean the terminals up, but wasn't expecting a terminal that was new 30 months ago to be quite so corroded.



After cleaning it up, it's clear than one side of the terminal has lost about 50% of its metal both the steel bolt and brass terminal were affected.



Only affected one side , other was perfect.


It's the positive terminal on the link cable between the 2 batteries, the nearest cell was a tad low on electrolyte, so it looks as if the battery has been overcharged, odd as I fitted an alternator to replace the Dynamo, one of the reasons for this was to keep battery maintenance to a minimum, looks as if I'll have to check the output!

The other 3 terminals are perfectly clean.

Dave

[Rick]

On a related note, with the jolly green giant, it didn't take long for the 6v battery (that looks after everything bar the starter motor) to cook itself and split open. I'd thought it was just a one-off, especially as the charge into the battery didn't read high on a meter. So I replaced it. And the same happened again.

I can only think that the battery was overheating. It sits under the front floor, under the passenger's feet beneath a panel. The (hefty) exhaust runs quite close to the battery, below it.

I've now wrapped the exhaust, that has reduced its temperature significantly in the area of the battery, especially as it's not really in the air flow, so I'm hoping that it's now fixed. I also tend to run the engine with the top cover removed, unless someone's sat with me.

Sorry for rambling, as it's a different problem to the one you've had

RJ
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[goneps]

Dave,

I had a similar problem on the Morris, but it was caused by a rebuilt battery being inadequately sealed around the terminal post; consequently acidic vapour from charging was corroding the terminal.

It was the second time the battery had been rebuilt, because original-style rubber-cased 6v batteries are not sold in this country. Unfortunately the battery man couldn't obtain new pitch to seal the top, so had to reuse the old pitch, which as mentioned was less than ideal.

Based on this experience my guess is that you might have a similar problem with gas escaping around the terminal post. The fact that only the one terminal is affected seems to point that way.

Richard