Battery Terminal Corrosion

[Michaelr11]

What might cause a lump of corrosion to be growing on top of my battery negative terminal and cable. The battery is a sealed AGM battery, with a resting level aound 12.75 volts. The flakes are what I typically see on a car battery but I've never seen it on my bike batteries before.

 

I mixed up a solution of baking soda and water and washed the whole thing clean, then I coated it with dielectric grease.

 

Any other cautions or suggestions?

[Alfred02]

Sounds like your battery has slightly vented at some stage.

You have done already the best you can do to restore the condition as well as possible and to prevent any further mishap.

There is a likely chance that you could end up with the black wire syndrome. On small fine wire, it will actually make the wire brittle and none conductive.

On the larger heavy cable as used on bikes and cars, it's the surface on each strand that will turn black and exhibit increased resistance.

If this happens, there are just two options that I know over 20 years that worked for me.

 

1)Replace the cable itself.

2) Cut off the ends and re-terminate, then solder/ tin the ends to prevent further or renewed built up.

 

As on the heavy cables, it just effects the outer surface, it doesn't appear to increase the resistance/current carrying capability of the cable itself, as long as the ends are redone as mentioned above.

[racer7]

Its not unheard of for a lead acid battery to leak a bit around the terminal penetration, especially if heated as in a rapid charge. The acid rapidly promotes a corrosion ball especially if widely dissimilar metals are on the terminal in contact with the acid (eg lead terminal post, steel bolt and nut, copper and or aluminum contacts, etc etc).

If you clean it off and it reoccurs rapidly you probably ought to just change out the thing so it doesn't become an ineffective ground and leave you stuck somewhere with a dead battery after failing to charge while riding.

 

But this can also happen from a small spill or venting episode as a one time event so for now watch carefully if it seems to be working OK.

 

Note the above post on "black wire"- good advice...

 

I've been unimpressed by the quality of cheap Asian AGMs showing up in such large numbers so would not be surprised to see a leaker. I've seen several instant death episodes which probably relate to poor control of lead alloys used- its easy to get lead too brittle with too much antimony in the recycle and I doubt they control for it very well. There's a reason I prefer to spend a few extra $ for an Odyssey and they're still way cheaper than BMW OEM with more starting punch by far...