Cells with water damage - would you use these?

R

runsnbunsn

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I recently got a lattop battery which has seen either a lot of water or maybe even was diving a bit.
The PCB was covered in blue dust...
The cells are very rusty, but - to my suprise - show all six a voltage of 3,76V

Not sure if I should clean them with WD40 and put them to use, the rust could have gotten under the positive terminal cap and may couse a short there at some point, right?

Attached some pics..


image_euhzen.jpg

image_dfhepb.jpg

image_ykdcqa.jpg
 
WD40 will do nothing, you'd get similar results using saliva.

Those cells will likely be fine, that looks like surface rust, but test them and find out.
 
I BIN all cells that look damaged. It doesnt matter... In my world you dont save any money in trying you only lay sleepless during the night.
 
Clean with clean dry toothbrush & WD40 or Lanox.
Treat with Lanox after soldering wires for longer term.
Lanox leaves a nice protective film, WD40 evaporates to nothing (=kerosene & light oil).
 
Pull the cover off one, If there is rust in the joint where the top cap meets the base then pitch it. If its just on the exposed surfaces then they are fine to clean and use
 
As far as those images show there is no damage, just rust staining, most of which is concentrated on the terminal insulator (which isn't metallic) - if you've got 1000s of cells to play with you can be fussy about what is used, but I'd certainly have no issues with cleaning the ones shown and testing them.
 
Sean said:
As far as those images show there is no damage, just rust staining,
Click to expand...

Negative ghost rider.
In this image you can clearly see damage on the POSITIVE end. Once the rust has gotten in to the CID area, it is definitely compromised, as Mike brings out.


image_ykdcqa.jpg


If there is "any" rust on the Pos end, toss it. If there is any bubbling of rust anywhere on the casing, toss it. If the rust stain is only on the wrapper, you are possibly safe to use it. But I still wouldn't put it in the production of a powerwall application, though, imho.
 
I see surface rust, probably just staining from elsewhere, let me know what app you are using thats letting you view the internals please Korishan.
 
You don't have to have xray vision to see damage on the CID.

And how about you show us proof that it is "probably" surface rust. Just saying it "looks" like surface and saying it's ok, is not good enough.

If you have no problem using potentially damaged cells in your applications, by all means, go for it.

If a cell "looks" damaged, it is not worth the chance of loosing ones home, building, vehicles, property, life over. Don't risk it. You wouldn't take a cable that has some frayed strands and expect to hold your car up with a lift while you work under it, would you? Probably not.
 
There is no way I would use those cells with rust on it...

But if you like the live on the edge, I have some frayed cable I can lend you for rock climbing haha.
 
guys, thx for the input! :)

I removed the plastic from one of them, just to b sure. No rust UNDER the cap as far as I can see. But the risk of getting rust there while cleaning the cell.

The powerwall is going to be used in a remote location where I am only maybe once a week, or less. So for safety reasons I'll toss them...

image_wnjldp.jpg
 
Nope not worth it. I have quite a few like this that I've put aside that I deemed not worth salvaging. They are typically left in a metal drum at the bottom where water was accumulating. The rust is just hard to get rid of and will interfere with your solder joints, etc. Removing the nickel coating by sanding just make the rusting easier, especially if you use flux. The biggest concern is just safety. But if safety is not a big concern, such as your powerwall is located away from the premises, then sure put it together. I'd suggest putting all of it in one pack so if you run into issues later on it's only isolated to that pack.
 
I have some of these set aside for random projects but I will probably never use them. I actually took one and put it into an ultrasonic cleaner haha. Worked out just fine but I wouldnt recommend it.

What I worry about is that its not from water but the electrolyte that has come out of the cell as we have all seen on some cells. The electrolyte really rusts fast! So its hard to tell sometimes...
 
I cant be more clear in this area but on the positive end you do have mechanical function just below that top. That one is exposed in such a way that rust on the top will compromise the function.
If above is compromised or not we cannot tell BUT what we can tell is that we have corrosion in that area that with high potential can cause issues.

I would never allow any one in my area to use such a cell in anything except experiments far from any living human or house.
You can run a system without any fuses as well but would you do that?

"I see rust" - That should be an indication that there have happened something to the cell and it should be considered faulty.

In our DIY world we need to have the mind set of "better safe than sorry" If we dont have that we will end up with images of fire and other issues im afraid. If we can rule out 1 potential issue lets please do that!
 
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