Battery fumes and aluminum. Any chemists out there?

[jameshtaylor]

Odd problem. My battery is held in place with an aluminum strap. Fumes from the battery vent seem to be eating the aluminum! Left untouched for 3-4 weeks, the aluminum next to the vent is covered with a baking soda-like powder. Anyone encountered this problem? Would powdercoating the aluminum help?

[Flieger]

I would expect acid fumes to corrode any metal in that situation. I think powder coat would help but you should just keep an eye on it, clean it occasionally, and replace the strap as necessary.

[Leeloo]

Acid plus metal makes for hydrogen gas and the oxidized metal. Classic 'popping dog' experiment in freshman chemistry. Dilute HCl or sulfuric acid and toss in some aluminum or zinc, cover with thumb while bubbling, then release near a bunsen burner.... "pop" goes the hydrogen in to water.

L

[jameshtaylor]

Thanks.
Yup. Corrosion is what I have. What to do? Will powdercoating or paint hold it at bay, or am I condemned to cleaning the surface every week until I can mount some different kind of battery?

[davep]

powder coating seems to be a bit porous and the acid would tend to cause damage under the coating before it erupted into blisters.

[jameshtaylor]

I'm thinking duct tape, or maybe a plastic tape might do the trick. I'll experiment a bit and report my results.

[chris_seven]

If you have to clean off the aluminium sulphate every couple of weeks then it sound very much as if you have other issues with your battery and charging circuit.

I would check battery temperature and look at the regulator as well.

[orange911]

Ideally, you want to vent the fumes to the outside, this is not always possible - unless someone has a open hole to run a hose to. The other option which is easier, just let her sleep with the hood open.

[jameshtaylor]

Hmm. Voltages in the car suggest the charging circuit is working normally but you raise an interesting point. I think we'll have the regulator checked. It's interesting I've not seen this on a car before.