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MG TD TF 1500 - battery sulphiting / corrosion - how to stop?

Always been a niggling query... how does one stop the battery terminals from going furry white?

Went to visit the TF today and yep, the +ve (gnd) terminal has gone furry.

Have always flushed it away with a kettle of boiling water, then keep rinsing with a bit more water.

Bought a can of CRC stuff that's meant to clean & protect... but it ain't doing much.

Some used to coat terminals with Vaseline, dunno how effective that is - bit too messy though.

Any chemists here that know what's causing it? Is it because the battery is under/overcharged, or is airflow too limited? Acid too concentrated? Acid spilling out?


How well do these 'solutions' work:

- gluing a copper penny to the battery top?

- neoprene rubber discs on the terminals?

- felt red/green discs?

- same felt soaked in oil?


TIA!
Will

Will,
I use the felt disc and a light "smearing" of Vaseline or light oil on all our cars...seems to work well.
Last mechanic that worked on my pick-up "painted" the post...that worked well untill I scraped it off to give someone else a jump! With a dozzen cars around here something always needs a jump so I am not a big fan of "painting" them!
Cheers,
David 55 TF1500 #7427
David Sheward

Will - Instead of washing with just hot water, pull the battery and use a water baking soda mixture to neutralize all the acid residue on the battery case (make sure none of theis mixture gets inside the battery). Coating the terminals with some kind of grease helps to keep the acid off of the terminals, but doesn't last for a long period of time. The treated felts also help, but are not 100%.

The next time you have the car out on a drive, after stopping , leave the engine running and check the battery to see if it is boiling. You may have a overcharging problem that is causing the electrolite to boil and thus drive some of it out of the battery. This is bad for the battery, the terminals and any surrounding metal. YOu should also check the voltage on the battery terminals when the engine is reved up above 1000rpm, say around 1500 to 2000. If the voltage is higher than about 14.5 volts, then your regulator needs to be adjusted down to achive that voltage (I know, the says 15 -16 volts, but that was for the older batteries - todays batteries live more comfortably at 14.5 volts). Good luck - Dave
David DuBois

Will,
I always use a smear of acid-free vaseline: works perfectly. Specially with a modern type "closed" battery. If your car still has the older model (the one you can refill),you should be able to drive without the problem occuring for at least two years...
If not then I think, just as Dave says, you have a problem charging the battery.
Good luck !
Nick, 52TD/63midget.
D.G.J. Herwegh

My battery sulphites when sitting. I have a shut-off connected to the positive terminal, and the sulphiting "grows" even with the battery disconnected. I have the felt disc; and have tried the CRC product. It still grows "white "whiskers." The battery is a relatively new Eveready-brand.

Any other suggestions?

Ira

Ira Spector

Buy a totally sealed battery and clean the terminals with wire brush until they are pure lead. Then coat with silicone di-electric grease. Make sure you tighten connection as tight as possible Never had a problem with this set up.
Colin Stafford

Some batteries leak gas up around the posts, which is what causes the corrosion. Silicone di-electric grease will stop the problem, and won't evaporate or wash away.
S.R. Barrow

I had to weld new steel into the bulkhead where the battery post fur had eaten away a hole. I've seen a number of other cars with the same problem. Since then I have turned the battery round so the terminal are to the front. If you do this check though they don't touch the bonnet.


Jan T
J Targosz

Thanks guys, just a quick update.

I couldn't resist, I boiled up another kettle and gave it a rinsing. (I have a kettle just in the garage for that)

Maybe just a bit overzealous, as have discovered there's probably some leakage between battery crate into passenger footwell... ;)

Ah well, nothing like the engine heat from a 50mi drive at 11pm didn't cure.

:)


BATTERY: I don't like "maintenance free" and always buy the vent caps.

I find new batteries today come with very low liquids (barely covering plates) and 2" below the top; I usually top them up to 1" below. Usually about 0.5L worth of water! ... overfilling?


CUTOUTS: yeah, battery is disconnected when car is parked. Both terminals...!


VASELINE: didn't have any, shot it with some WD40 for time being.


BICARB: yea I stocked up at the supermarket; found some new uses for it too. Great for polishing rust stains off chrome...?!


Regulator: suspect mine's probably switching off sooner than it should, around the high 13s mark. Ammeter sits on zero after about 30 secs of driving on freeway at 3500rpm.

Which is when I discovered the 9V batt in the DVM is shot; I keep a DVM part of car's toolkit. Darned modern battery-sucking electronics... :P

Will

Will - I don't know why you dislike the maintenance free batteries. Contrary to their name, they do have caps, they are under the large rectangular patches on the top and can be removed by prising them up with a putty knife. Underneath you should find that the thing you don't like about other batteries has been rectified. The electrolite level in maintenance free batteries is much deeper than in normal batteries (thus maintenance free - you should not have to add water over the life time of the battery, but you can if you wish and you can check themat any time). The other advantage of the Maintenance free battery is that the venting of the cells is through that same rectangular patch and directed away from the top of the battery, thus acid laden vent fumes don't get on the battery terminals. The best buy I ever made was one of the first maintenance free batteries marketed by J.C. Pennys back in the days whe they had an automotive section. It was advertized as a lifetime battery and was gaurenteed for as long as the original owner had the car. I bought one of these in the mid 70s for the TD and I have never had to buy another battery since then for it. Over the past 30 years, they (or Firestone, who took over the warrentee items when Pennys colsed the automotive section) has replaced the battery absolutely free whenever it will no onlger hold a charge.

If you don't have any vasoline, the silicone dielectric grease that Scott recommends will work, as will plain old wheel bearing grease (talk about messy).

To answer your question about what causes the furry growth on the termainals is is just the reaction of the lead to the acid being deposited on them and is just a corrosion deposit. In this vain, although it is picking nits, sulfiting is a term used to describe the coating of the internal plates in the battery with sulpher or sulfite from the the sulpheric acid used in the electrolite. This takes place when the battery is allowed to remain in a discharged state for long periods of time. Cheers - Dave
David DuBois

Try washing down with good old fashion Phenol
Bob

This thread was discussed between 07/05/2005 and 15/05/2005

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