Battery Terminal corrosion/why after many years

[Roc]

Rather than add to the existing topic which is about prevention (which I copied the link below), here is a new thread about what I'm seeing on the terminals. 

http://c34.org/bbs/index.php/topic,7201.0.html



I've had 6 volt golf cart batteries since 2009 and they've been working great, and still do.  For the first time, last year I noticed white powder (corrosion) on the negative terminal.  I cleaned it with a water/baking soda paste, wiped everything off and assembled together.  This season, I've noticed the same thing (not as much as last year).  Up until now, the terminals have been spotless.   I see that this is usually the result of improper charging.  I have a Truecharge 40 (at least 10-12 years old model, not the newer model, but original Truecharge design), and it seems to be working same as usual.  I have a digital volt meter and I can see the charging sequence looks correct.  I have the settings at "Flooded" and "Charge/bulk/absorption".  I have a temperature gauge, so the temp setting is not used.  I also notice green corrosion on the positive terminal, right where the shrink tubing ends, but not on the terminal itself. 

I do realize, the terminals are not "tinned" as Mainesail suggests, however up until recently, they have stayed clean.  When I cleaned the terminals last year, I did rub some Super Lube on them, but maybe I didn't put enough?

Pictured is the negative post.  You can see white powder.  The other negative post has the temp gauge, which the terminal appears to be very clean.  The last picture is the positive post and you can see green corrosion near the shrink tubing.

Interested in any feedback on this.

[KWKloeber]

I think the wisdom is whether corrosion occurs on the neg vs positive, determines whether the battery is being over- or under-charged.
Have you checked specific gravity, etc. and more carefully investigated whether it ie being over/under?

I typically stick a sacrificial copper penny somewhere on the top of my auto and boat batteries -- not right alongside a terminal.

ken

[Roc]

How would a copper penny tell you which terminal if it's not close to either the neg or pos terminal?

[KWKloeber]

How would a copper penny tell you which terminal if it's not close to either the neg or pos terminal?

it's just sacrificial, not troubleshooting -- it "attracts" the corrosion before my terminals do.  Kinda like a shaft zinc, but not.