Sciencemadness Discussion Board - Recycling a car battery

Recycling a car battery

Gearhead_Shem_Tov - 1-11-2017 at 21:43

My 'maintenance free' car battery karked it yesterday.

As far as I can tell, I can get roughly $6AU for the dead battery from a scrap yard here in South Australia. After I schlepp it to the scrap yard.

I'm thinking instead I will salvage what I can from it, the acid, the plates, the terminals. Perhaps I could even rebuild it in a (deeper) acid-proof container to make an old-timey "accumulator" like they show in "electrical experiments for boys"-type books from the early 20th century.

Has anyone tried doing any of these things? I'd be curious what your experience has been.

-Bobby

VSEPR_VOID - 9-11-2017 at 15:37

Those batteries may be high in D2O

Melgar - 9-11-2017 at 19:16

I'd imagine that the main danger comes from the fact that it's mostly lead by mass. And that lead is probably going to be in the form of gunk that's all over the inside, if it doesn't work anymore. I'm pretty sure that the lead in car batteries has quite a bit of zinc in it, and possibly other metals too. That might need to be dealt with somehow. Don't bother trying to salvage the acid, it's like 20% H2SO4 that's going to have all sorts of shit dissolved in it.

Really, you should assume that the only thing of value you'll be able to salvage from it is lead metal, so make sure you know how to separate that from everything else, and how to convert lead oxides and sulfate into lead metal. The rest will have to be disposed of as hazardous waste, properly. Most countries have certain days during the year where individuals can turn in hazardous waste for free, to prevent them from throwing it out in the regular garbage, I assume Australia does too.

It's probably a good idea to get some lead test strips, just to test anything that might have been contaminated with lead salts. They're available online, and at hardware stores, where they're used for testing old paint when doing remodeling projects.

diddi - 9-11-2017 at 19:47

the Pb is contaminated with Sb, which improves hardness (esp for the terminals) it is a shit job that stains everything dark brown and the yield is very low because it is in the discharged state. converting all the Pb ions back to Pb from insoluble mess is not worth the effort.

PirateDocBrown - 9-11-2017 at 22:31

There's a few YT vids on this.

Start with King of Random's:

https://www.youtube.com/watch?v=SgGhNfJfSK0

Gearhead_Shem_Tov - 11-11-2017 at 02:42

Thanks for the video like, PirateDocBrown .

Really, though, I'm more interested in salvaging the lead plates than in recycling them for their lead content. If at all possible I would like to rebuild a version of the lead-acid battery from its components.

I know this is not a cost-effective thing to do. I'm approaching it in the spirit of recreating projects I've seen in century-old issues of Popular Mechanics or Popular Science and in books such as "The Boy Electrician" by Alfred P. Morgan. It's an aesthetic thing, for fun.

As for the alloying elements in the lead plates, I believe modern batteries are more likely to have calcium alloyed in their plates than antimony. This apparently reduces hydrogen gassing. I don't know about the alloy used for the terminals, though.

What would be a simple test for Sb?

-Bobby

Melgar - 11-11-2017 at 07:07

The plates will probably not be intact anymore. Hence, the reason that your battery stopped working in the first place. You'd need to recycle the lead and cast new plates or something, if that's your goal.

unionised - 11-11-2017 at 09:53

It is entirely possible that some cells still work fine.

Melgar - 11-11-2017 at 10:04

Quote: Originally posted by unionised

It is entirely possible that some cells still work fine.

It's still going to be comprised of "failed" and "about to fail" cells, even if some are more degraded than others. Engineers take courses on how to design things so that all the parts that are expected to fail sooner or later, wear out around the same time. If some of those plates looked like they had a lot of life in them when the battery died, that's actually a sign of bad engineering.

Gearhead_Shem_Tov - 11-11-2017 at 16:59

Even if some plates are damaged, I'm hoping that some will be usable. It will result in a smaller capacity battery, sure, but it should still be interesting.

-B

S.C. Wack - 12-11-2017 at 06:29

The spongy Pb will be in worse shape (much more delicate) than the PbO2. The PbO2 that remains on will mostly want to stay on, with more or less good coverage. The Pb not so much.

RogueRose - 12-11-2017 at 06:48

Quote: Originally posted by S.C. Wack

The spongy Pb will be in worse shape (much more delicate) than the PbO2. The PbO2 that remains on will mostly want to stay on, with more or less good coverage. The Pb not so much.

Really? I've had the total opposite experience in the batteries I've taken apart.

[Edited on 12-11-2017 by RogueRose]

Texium - 12-11-2017 at 07:31

I actually also recently acquired a dead car battery from a friend, which I plan to take apart when I get a chance. I'll post about my findings here when I do.

Mabus - 12-11-2017 at 08:12

I too found a dead car battery last year, and planned on taking it apart, but after I discovered it's a very effective doorstop, I decided to postpone its "autopsy".

unionised - 12-11-2017 at 08:42

Quote: Originally posted by Melgar

Quote: Originally posted by unionised

It is entirely possible that some cells still work fine.

Sure, but I have pulled apart a few batteries in my time. My experience is that examples of "bad engineering" are quite common- I guess it's because the temperature in the cells is usually different.

S.C. Wack - 12-11-2017 at 15:29

Quote: Originally posted by RogueRose

Really? I've had the total opposite experience in the batteries I've taken apart.

Is there a difference between original and replacement?

Gearhead_Shem_Tov - 13-11-2017 at 03:40

Quote: Originally posted by S.C. Wack

Is there a difference between original and replacement?

I'm not sure what the photos are showing. Difference in colour, of course.

-B

Melgar - 13-11-2017 at 07:05

Quote: Originally posted by unionised

Sure, but I have pulled apart a few batteries in my time. My experience is that examples of "bad engineering" are quite common- I guess it's because the temperature in the cells is usually different.

Well, that's only ONE sign of bad engineering. In this case, it'd be cheaper to have the plates be interchangeable and only need one mold for them, rather than to optimize the dimensions of each one for maximum life at that particular spot. Because recycled lead-acid batteries are returned to their respective factories anyway, I'd assume the QA guys would be tallying up their failure modes and relaying the data to R&D.

[Edited on 11/13/17 by Melgar]

unionised - 13-11-2017 at 10:27

Quote: Originally posted by Melgar

[
Well, that's only ONE sign of bad engineering....

[Edited on 11/13/17 by Melgar]

It's the one that is relevant to the thread.

S.C. Wack - 13-11-2017 at 13:41

Quote: Originally posted by Gearhead_Shem_Tov

I'm not sure what the photos are showing.

My response, being that it was not my imagination little of the Pb and the grid it's on compares to the condition of the PbO2.