Problem with Negative Terminal Corrosion

[DefinitelyMe]

Originally Posted by Stu Jackson

How long does it take to build up that much?

Ventilate, ventilate, ventilate, just like the rest of your boat. Consider not letting it get that bad!

Took about 8 months to get that bad. I agree though, best not to let it get there, which is why i'm trying to find a permanent fix now rather than just cleaning it occasionally.

OK, the guy from Lifeline got back to me very quickly and said, 'That is definitely without a doubt a leaking battery terminal'. He also said that the failure rate is 1/4%................ so, since i have 2 that have failed, if my maths is correct, i am one in 160,000 (1/4% x 1/4%). Unfortunately, i bought the batteries 5 years ago and the warranty for manufacturing defects is 5 years............. so it looks like i should have got in touch with them when i first noticed the problem a year and a half or 2 years ago. Doh! He did offer to replace them at a discounted rate though.

He suggested using ammonia to minimise the return of the corrosion. Makes sense as ammonia is a weak base. I think i'm going to do a combination of all the suggestions you guys have come up with. Clean using some of that stuff, grease around the base of the terminals and put some ammonia on top of the grease to neutralise any further discharge. Further suggestions are still welcome. Cheers!

[DefinitelyMe]

He's also offered to honour this discount in a little while once the battery finally gives up. Pretty good customer service methinks.

[MBWhite]

In regards as to how to clean terminals with corrosion on them, I have tried pretty much all of them from baking soda to coke, to ammonia, brake cleaner, petroleum products of several different flavors, etc.

My preferred method any more is just plain water, but copious amounts applied when you do.

Just run a garden hose on the battery for a few minutes. No brushing or scrubbing needed unless the battery is dirty or oily, then using a rag under flowing water will pretty much clean everything satisfactorily. Here is an example:

Tractor battery needing replacement






Same battery about 7 minutes later:



Keep in mind there was no scrubbing involved here, just water from a hose. It is such an easy thing to do if you have access to running water, and it prevent holes getting eaten into your clothes when you have to hike an old battery out.

When the new battery is in, or the terminal connections cleaned, just seal the terminals with something. You can use one of the many sprays (I do this whenever possible) or just anything that can seal out vapor- vaseline, wheel bearing grease or clear spray paint all seem to work the same which is pretty good.

[Reefmagnet]

the old-timers fix is a jug of hot water poured over the terminals to clean off the gunk followed by a coating of Vasoline.

[kentobin]

Originally Posted by Reefmagnet

the old-timers fix is a jug of hot water poured over the terminals to clean off the gunk followed by a coating of Vasoline.

Over 40 years ago battery manufacturers were teaching auto mechanics that vasoline would work it's way between the battery post and the cable clamp and act as an electrical insulator. Aside from highly not recommended no other information was given as to how serious the problem might be.

They recommended using some type of fibrous washer impregnated with an electrolyte neutralizer that fit over the battery post and under the cable clamp. After installing the cable clamp spraying the whole thing with the same chemical in the washer.

The other recommendation was just paint the post and clamp after you installed the clamp.

No idea what they recommend these days. Not sure how long I'd remember the information anyway. :-)

[Reefmagnet]

Originally Posted by kentobin

Over 40 years ago battery manufacturers were teaching auto mechanics that vasoline would work it's way between the battery post and the cable clamp and act as an electrical insulator. Aside from highly not recommended no other information was given as to how serious the problem might be.

They recommended using some type of fibrous washer impregnated with an electrolyte neutralizer that fit over the battery post and under the cable clamp. After installing the cable clamp spraying the whole thing with the same chemical in the washer.

The other recommendation was just paint the post and clamp after you installed the clamp.

No idea what they recommend these days. Not sure how long I'd remember the information anyway. :-)

Yeah, seen those washers and my car when new had the painted post - kind of like a gun metal blue. I think it''s a bit of a furphy with Vaseline acting as an insulator however. I've used lanolin grease - which has a dielectric strength of around 70 kV - with great success on low and high current terminals over the years and never experienced any issue. In fact I find the opposite to be true because the grease prevents corrosion which is the main cause of problems. Some boat electronics manufacturers also include a little tube of silicon grease with their products for the same purpose.

[kentobin]

Originally Posted by Reefmagnet

Yeah, seen those washers and my car when new had the painted post - kind of like a gun metal blue. I think it''s a bit of a furphy with Vaseline acting as an insulator however. I've used lanolin grease - which has a dielectric strength of around 70 kV - with great success on low and high current terminals over the years and never experienced any issue. In fact I find the opposite to be true because the grease prevents corrosion which is the main cause of problems. Some boat electronics manufacturers also include a little tube of silicon grease with their products for the same purpose.

Hello Reefmagnet,

Most of those cable terminals were on so tight I couldn't see how anything could migrate in there myself. Quite often I had to use a terminal puller to get them off as they seemed to have bonded with the metal battery post. On the other hand I had no reason to doubt the battery vendor. Personally I've never used anything but a little elbow grease to keep things clean. :-)

As to silicon grease I can't remember the boat guy I talked to but he said it was an insulator and to put a stainless steel lock washer with the external teeth between each screw and crimp on connector in the fuse box when you use it. That was the only way he felt you could get a reliable connection when you used it and he did recommend using it.

I am interested in DefinitelyMe's problem but don't have any ideas there.

Ken