BajaNomad

Brown battery corrosion

Santiago - 8-30-2007 at 01:34 PM

The other day I pulled the covers off my batteries in my aluminium boat and one of the batteries had a dark brown corrosion on both terminals - cleaned off with baking soda just like the usual yellow/white powder I'm used to. Other battery was clean. The batteries are selected for use thru a Perko dual battery round switch (select 1, 2, both or off). I store the boat out of the water with the battery selector in the 'off' position but this time it was in the #1 position which was the battery with the odd corrosion. The batteries are about 3 years old and are Trojan starting marine type. Is this stuff diagnostic to anything?

Barry A. - 8-30-2007 at 01:46 PM

Wow-----the color of that corrosion throws me-----I have never seen any other than the normal chalky white goop.

Barry

MICK - 8-30-2007 at 02:15 PM

The reason for the corrosion was, somewhere you have a small draw with the battery switch on. It could be as small as a loose conection on a wire somewhere. The corrosion that is brown is the beginning of the white corrision. As long as you can shut off the batteries I wouldn't worry about it. If you had to clean the battery I would recommend taking the terminal off and cleaning it as the baking soda doesn't always soak in. Good lu ck
Mick

Hook - 8-30-2007 at 03:07 PM

You might try isolating where the drain is by testing for current by hooking up a 12 lightbulb with leads in line with your negative lead. In other words, make this bulb connection the last link between your negative battery lead and your negative battery post. You could also do this with a simply voltmeter but it may be easier to VISUALLY verify current draw from a distance by observing the bulb.

If there is a drain, you should see it glow. Next, begin pulling or tripping fuses to see which one interrupts this flow of current. You can at least isolate it to an individual system, possibly. It's probably occuring somewhere near the fuseblock. Some draw may be unavoidable especially if there are any electronics that draw a small amount to keep a memory or run a sensor. But on a 16 foot tin boat......not likely.

Keep EVERY ground terminal clean as a whistle so that current doesnt try to find other paths back to the ground.

"corrosion" is really just oxidation...

Mexray - 8-30-2007 at 09:41 PM

...rearing it's ugly head on the battery terminals.

Every connection, no matter how tight and good looking it may seem, has a small amount of 'resistance' at the point the two components contact. When you have dissimilar metals touching, there will be an 'interaction' between the two...if you have left the battery hooked to a complete circuit, no matter how small, the dissimilar interaction will be enhanced.

The brown color you experienced may be a reaction to the surrounding atmosphere - or some material nearby that reacted chemically with the metals in the cable or the battery terminal or the terminal bolt, the bolts plating, etc, etc...Moist salty air near the sea doesn't help any either!

To help 'cure' this oxidation problem, you have to keep the 'oxygen' away from the terminals...a tough job, indeed...

My best solution is to properly clean the components involved...your baking soda helps to neutralize any battery acid nearby...wire brushing the parts back to a new like state is the best.

Secure the cable tightly to the battery terminals with clean hardware that doesn't have any left over corrosion on it.

Then, coat the entire connection with a heavy grease...this coating will help keep the oxygen away from the metals and help prevent future corrosion...don't forget to put some grease on the undersides of the cables - maybe smear some on before securing the cable...some use petroleum jelly, which works, but must be redone periodacally...the heavier the grease the better, as it won't flow away as easy...the old military cosmolene was the best...light stuff like WD40 works but would have to be redone monthly.

Once corrosion appears, it's hard to keep it from coming back...but the above will sure help to keep it to a minimum!

All this comes from too many years in the battery business...hope it helps!

Diver - 8-30-2007 at 09:45 PM

What are those little blue or red felt rings they put around your terminals to help stop corrosion ?

bigjohn - 8-30-2007 at 09:55 PM

I believe the felt rings are red because they are soaked in transmission fluid. I believe that is helps to reduce the amount of oxidation.

[Edited on 8-31-2007 by bigjohn]

Bob and Susan - 8-31-2007 at 05:23 AM

what are the "blue" ones soaked in???:lol:

bigjohn - 8-31-2007 at 07:03 AM

curacao??? :?: :lol::lol:

Sharksbaja - 8-31-2007 at 11:24 AM

Mexray gives a good solution. Once you've determned that you have no or little voltage drop proceed to do what he says. They do make a grease specifically for electrical (DC) connections but I've forgotten what it's called. It is a white substance. Looks much like zinc oxide.

Red and Black Felts...

Mexray - 8-31-2007 at 09:39 PM

...are a good idea for top post type batteries...they are red and black to color code them for Pos and Neg terminals...

I haven't heard about the red ones being soaked in ATF, but it would work fine, IMHO. Any type of lube would work, as it helps to coat that area underneath the cable's terminal end.

I spray those felts with WD40 when I install batteries at my shop...I also advise to recoat them when you change your oil, etc, as the lube tends to flow away with time...

We used to us a black tar-like coating that was made by an outfit in an eastern state. It was really nasty stuff, and when you coated a terminal, it stayed coated! It was almost impossible to get off your fingers, kinda like pine tree sap!

That's about all the 'felt' info fit to print....;)

Santiago - 9-1-2007 at 03:13 PM

Thanks!
Mexray - I drive past your shop (I think it's yours) on my way to Discovery Bay a few times each year -next time I won't be in such a hurry - but then - you'll probably be in Baja!

Bob and Susan - 9-1-2007 at 03:15 PM

yea mexray...when IS your next trip???

bring mrs mexray too...

Al G - 9-1-2007 at 03:33 PM

Quote:
Originally posted by Sharksbaja
Mexray gives a good solution. Once you've determned that you have no or little voltage drop proceed to do what he says. They do make a grease specifically for electrical (DC) connections but I've forgotten what it's called. It is a white substance. Looks much like zinc oxide.

Dielectric grease...but maybe not heavy enough for batteries???
They used to make a spray-on red sticky stuff, that I found easy to use.

TMW - 9-2-2007 at 09:50 AM

Battery shops sell a spray for the connections. I keep a can at my generator sites.

Santiago...

Mexray - 9-2-2007 at 09:59 PM

...Yes, that's us, there on Hwy 4, about 1 mile West of I-5...stop by any old time...

Bob & Susan...current plans are for us to head South in early October...we're waiting for your pool to be filled with warm water...:lol:

Will drop you a note in case there's something we can lug along for you guys...