While adding a bit of water to the battery cells in my wife's 2006 XK8 on Saturday afternoon, I noticed a moderate amount of white powder on the trunk's floor around where the battery sits. No water or moisture at all, just a powdery substance that smells somewhat caustic. I did not notice any cracks in the part of the battery casing that I could see without removing the battery for a closer inspection. It is a Bosch vented battery that I installed in September 2012 and it has given me no other issues thus far. The vent tube remains attached to the vent hose and I assume the battery is venting properly but I'm not sure how to test for that....

Any ideas on what this is and what causes it?

(And no, we have not been transporting cocaine in this vehicle....)

 

That is battery acid and very bad for all metal.
Remove the battery and everything in the trunk.
Mix up a solution of baking soda and water and use that to neutralize the acid.
Then clean it all out, rust proof and bare metal that was exposed.

Then find out where the battery is leaking.

Cheers
Bill

 

It may be that your battery was not venting properly. Rinse the vent tube and replace, remove one of the fill ports and gently try to blow through the tube.

 

Yes having the vent connected correctly is important.

 

Dang, stole our thunder.

 

some batteries have dual vents. one at each end of the battery. the purchaser is expected to block off the unused one with the supplied plug.

 

I had a great experience with this kind of prob I will dig the pics out but it looked like the car was trying to make Oreos I kid you not

 

Yeah Jon, definitely the battery and highly corrosive. I had a flat battery on the XJ last week and when I popped all the covers, I was presented with a similar situation. Had some pretty aggressive corrosion attacking the hold-down bracket and pockets of it in the boot floor. I took a wire brush to it, then a palm sander, then painted.


I installed the battery from my wife's 05 S-Type that I'd replaced pre-emptively a couple of years ago (just b/c of age, was working fine) and I've kept it out in the shop on a battery-minder. Vent hose wasn't clogged - I made a mistake after installing it - I'd actually moved my battery-minders to the tractor and the Exc the previous week so figured I'd better put it on charge overnight after installation - and topped up the cells with distilled water before installation. I had a big puddle on the floor next morning from the vent hose. Read somewhere after that you should only top up after a full-charge.


Not entirely sure what the chemistry is behind it - just know I've seen it plenty in my vehicles that locate the battery under the bonnet and it is equally as corrosive there. First time I'd seen it on any of our Jags.

 

Thanks for all the feedback, guys. We're currently iced in with sleet and freezing rain, but when this stuff melts later today or tomorrow I'll jump on the battery issue. I really wonder where the white powder is coming from without any apparent water leaking from the battery cells since the trunk floor remains bone-dry, all six battery cell caps remain cranked down tight, and the vent hose remains firmly attached. Perhaps the source will reveal itself once I clear the trunk, remove the battery, and get a good look at the entire battery casing. I'll update this thread after I dig into the situation....

Thanks again for all of the advice....

 

Here's a couple of pics





Not sure if anyone has mentioned this but you need to stop it from progressing, make up a paste from bicarbonate of soda and brush it on the effected area, it should start fizzing, once stopped rinse off with water and repeat the process until no fizzing occurs, then you can treat the rust/effected areas and paint.... Once I was done this car looked like this...

 

Wow, what a mess! My wife's XK8 trunk doesn't look nearly that bad - just some scattered white powder with no evidence of rust-colored corrosion yet. I must have caught the issue long before you managed to do so....

How did you resolve your issue after trunk clean-up and refinishing? A new battery, perhaps? Did you happen to spot any cracks in your battery casing or otherwise make a determination of where this stuff was coming from? And what type of paint did you use for refinishing?

 

From what I understand the car was left on charge for a considerable period of time and I don't mean a trickle charger either, this would of "boiled" the battery probably causing caustic gases to cause the damage, the owner had no idea but i did need to supply, obviously a new battery and a new spare. The space between the tyre and the floor seemed to of been a good breeding place for the white powder and ate its way through the floor.

In the top pictures you can make out the rust patch, that had turned the metal to powder, the only thing holding it together was the paint. In the last pic you can make out roughly a 6" x 3" patch I had to weld in to fix it...... I replaced all the drain plugs as I had to knock them out to let the water and bicarb soda to drain away..... It was a helluva job!

 

Our battery has never been on a charger of any kind. I installed the battery myself in late September 2012 when the car's original factory battery began to die. The only action I've taken on this current battery is to add water to the cells as needed, probably on three or four occasions in the nearly 18 months since I installed it. I always make certain to screw each cell cap down as tight as possible after adding water....

Sure wish we could absolutely pinpoint exactly what causes this problem....

 

Jon,

Check the black plastic Vent Pipe isn't pinched shut anywhere along its length.

This is the OE battery in my 2005 XK8 4.2-S. The Vent Pipe was flattened as shown in the red circle and again before it exited through the grommet in the floor. Useless because nothing could vent through it. Fortunately I didn't get any acid spillage as a result.



I was careful when replacing the battery to straighten the Vent Pipe and route it so it couldn't close up again.

Graham

 

As was mentioned before, a lot of the batteries have openings for the vent tube on both ends. The opposite end needs to have a plug in it, the small red thing as seen here. Check for that as well.

 

I had the same exact issue with my car when I first purchased it. I noticed white powder was all over the spare tire area. I at first assumed it was some sort of cutting compound and worried about a possible accident in the cars past. I tried vacuuming it, unfortunately that spread the fine powder everywhere, i quickly realized the air being blown out was battery acid. I then made a baking soda mix to neutralize it and it was a real pain to clean up. I was very worried at the time that it might corrode the electric wires and such leading to electrical issues, but everything has been fine. The venting tube was in order but the battery had been recently replaced. I figured that the previous owner over charged the battery after a filling of water. But if others are having this same problem there might be some other cause, maybe the alternator itself is prone to overcharging an over filled battery?

 

If the vent is working correctly there should not be a problem. I think plums post#6 is likely the key to the problem. There are vents at both ends of the battery, and if the unconnected one is not sealed, the battery will vent to the well. When a battery is being subjected to a high rate of charge the hydrogen gas bubbles generated will carry a fine aerosol of electrolyte with them.

 

Just went to check out my current battery and it does indeed have the second vent as described above and it is capped, my guess is it was the OE battery previous to the one I got with the car that had leaked. Is it possible that over tightening the clamp can cause the battery to warp and leak? Anyhow, whatever you do don't try to vacuum it up, the powder is very fine and will get through your vacuums filter and get literally everywhere.

 

So THAT'S why there's a crack in my spare tire pan! I just noticed it today and was wondering what in the world could have caused it, and how I should repair. That's some pretty nasty stuff.

 

Crack is worse than cocaine isn't it?