Discharge around battery clamp

[ALAN COCHRANE]

Hi Everyone

For some time now I've noticed a discharge build-up on the battery frame clamp adjacent to the positive post. Here's a link to a photo I took earlier today:-

https://www.dropbox.com/s/ebcg56ec5xkzo ... 9.JPG?dl=0

I originally thought it was caused by the battery cell closest to the clamp tracking to the frame which was very close to it. I've since turned the rubber insulator on the frame round so that the long arm of the "L" now covers the frame at this point. This doesn't seem to have made any difference.
There's no discharge evident on either battery post or the other clamp. Any ideas what could be causing it?

Alan

[cactusman]

Afraid it looks typical of spillage of electrolyte from the adjacent cell cap. Check the cell is not over filled....the electrolyte should just cover the plates. make sure the caps are tight. A smear of Vaseline on the thread can help.

As far as the corrosion goes. Remove the battery and wash the affected area with a dilute solution of sodium carbonate (soda) to neutralise any remaining acid and rinse thoroughly with clean water. Repaint etc as necessary and refit the battery having checked the lids are tight.

[christopher storey]

Definitely acid corrosion, and probably as a result of venting from the adjacent cap . I would wash the entire battery down with sodium bicarbonate solution ( much easier to dissolve than carbonate which tends to be crystalline ) . You can also before doing this test with a sensitive voltmeter by putting one probe on the top of the battery case and the other to earth. If any voltage is shown there is clearly leakage of electrolyte, and a repeat of the test after washing should show no voltage

PS and, as Julian says, remove the battery and thoroughly alkaline wash the battery box area

[ALAN COCHRANE]

Gents

Thanks for the replies.
Yes I suspected that acid corrosion might be the culprit. I doubt it's leakage since the car has not turned a wheel in three weeks and the build up has occurred during this time.
I think it only occurs when the battery is connected and not when it's on charge. The photo is a bit misleading-I discovered the build -up when I decided to fully charge the battery ready for a weekend trip.
The battery is under a year old and the electrolyte in that cell appears to be at the right level-just above the plates.
I wondered if it may be caused by tracking from the exposed plate terminal to the hold down frame despite the insulating rubber being present. I may as an added test connect an earth from the clamp to the bodywork and see if the build up stops. The clamp to negative battery terminal is 2.3ohms which isn't that a great return path value.
I'm assuming the electrolyte having a charge is attracted to the nearest earthed metalwork, in this case the clamp-is this correct?

Alan

[cactusman]

You just need the tiniest amount of sulphuric acid to spill out or escape from the vent to cause galloping corrosion. Unless you really want the original look then get a modern sealed battery or one with a separate vent which can be connected to a tube that exits outside below the car. These usually have flush fitting cell caps with a cross head slot that can be opened with a 2 pence coin. They seal perfectly and any corrosive vapour is safely vented out below the car via a short piece of plastic tube. Sodium bicarbonate is equally good as a mild alkali wash.

[ALAN COCHRANE]

Well I followed your advice and took the battery out and gave it a thorough clean with sodium bicarbonate.When I tipped the battery to clean the base I noticed battery acid leaking out from the seam where the top and the side meet. Here's a closeup of area in question:-

https://www.dropbox.com/s/o1rk0vlm8349i ... y.JPG?dl=0

The leak is directly opposite the cap.

This seam is normally covered by the battery hold down frame so it's been subject to both venting and leaking. No wonder there was a rapid build up of acidic deposits around the clamp.
Anyway I'll be on to Lincon tomorrow for a replacement battery. Luckily it's still under warranty.

Thanks again for the advice.

Alan

[cactusman]

Afraid it is typical of the reproduction old style batteries. I gave up on them in my MGB.... They are hidden anyway. Unless original appearance is important I would get a refund and a modern battery, either sealed or with a vent and better tops. No leaks and nor corrosion.

[ALAN COCHRANE]

Well I seem to have fixed the battery discharge problem. I spoke to Lincon Batteries and they suggested one option would be to heat the top rubber coating to form a bead and reseal the side.
I was more than a little dubious about putting a flame anywhere near a fully charged battery but was assured that they did this all the time at Lincon. The important thing was to vent the battery gases for a few hours before starting.
I decided that this was a job that should be done outside in the garden. So dressed in my fire retardant overalls, full face visored safety helmet and welding gloves I got started. It turned out to be a very simple job and the battery was resealed in under a minute. I did both sides since there was some movement evident in the top of the other side plate.
It's now been in the car for two days and there's no sign of any discharge buildup. So, hopefully job done.

Julian

I take your point about modern batteries. I will certainly consider one the next time around.

Alan

[andrewh]

i had exactly this with the same battery. In fact I scrapped it and got another, it was out of warranty as the car had been in build. The new battery has exactly the same issue as yours. I think I will look for a nice modern in Black if I can find one to fit. I would rather not have leaks over my new car.

[Heuer]

I have the Antique Auto Battery one and it is superb: http://www.antiqueautobattery.com/ Not only is it an exact copy of the original Lucas (including logo and caps) but it features a gel battery inside the case. So no leaks and I did not even put it on trickle charge over winter. Car started on the button in Spring. The price is about the same as the Lincon battery but .............. you have to factor in shipping from the US which effectively doubles the cost. If, however, you have a means of getting the battery shipped over for nothing then most certainly worth doing.