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Homebrew Batteries

hanssummers.com

141 pointsxanderlewis19 comments

Hans is a friend of mine, and this is hosted on my VPS. It might be of interest to some that in order to handle the HN Hug Of Death on my little server, I've manually cached this page as HTML on the server and it's served via a rewrite rather than being served by the rather old CMS running an equally old PHP.

Doesn't a caching reverse proxy do this sort of thing automatically?

It would, if I had one.

YAGNI (you ain’t gonna need it)

Hi Geo, Interesting.

Has he done anything more recently with regards to homemade batteries, or was it just a passing interest?

Since this article no longer has comment submissions on the page itself, is it possible to add a little something about the chemistry for bleach and safe handling?.

While the experiments are interesting, I can't help but notice significant deficits in safety that might cause anyone duplicating this (at different scale) to have regretful issues, proper chemical handling isn't really mentioned.

I'm no chemist, but I do have a working knowledge with some of these chemicals related to water chemistry (pools).

Bleach (NaClO) naturally corrodes (oxidizes) metal because of its strong electronegativity from Chlorine. Any metal vessel is going to rupture as a matter of time, potentially creating conditions where hazmat cleanup may be needed, where reactants need to be safely neutralized before byproduct cleanup can occur; this is not intuitive since dilution may not be sufficient; its highly dependent on the chemistry of the formed byproducts.

For example, Sodium by itself (metallic) reacts violently in air which is why its often stored in oil.

Many of the potential byproducts of the experiment are hazardous, or carcinogenic, and there is a possibility that some may recombine at the electrodes. No mention of needed PPE is made.

The voltage differential across two electrodes unless externally driven (electrochemistry) is almost always driven by redox reactions (reduction / oxidation).

The solution may recombine into chlorine gas on the reduction side. There are other reactions that may also occur.

While I don't see too many unaddress-able issues at the small scale, if someone scaled this up as-is to get an appropriate level of voltage/current, I'd be worried for their safety.

The classic on this: "A Boy and a Battery", by Yates. (1959 ed).[1]

There's a whole series, "A Boy and a Motor", etc., all the way up to how to build your own model railroad from scrap, if you have the skills of a master machinist. Plus "Atomic Experiments for Boys". Really.

The Internet Archive has many of these.[2] "Shop Practice for Home Mechanics" is still useful, teaching how to do basic metalwork with simple hand tools. They cover lathe work, all the way up to how to make a crankshaft.

All this dates from an era before the availability of unlimited entertainment for timepass.

[1] https://archive.org/details/boyandbattery00yate/

[2] https://archive.org/search?query=creator%3A%22Yates%2C+Raymo...

Worth noting this is the old web site of Hans Summers of QRP Labs fame... https://qrp-labs.com

This may interest this audience, too: https://news.ycombinator.com/item?id=41235789 An open-source flow battery kit - Aug 2024 - 108 comments

Good example of quality scientific writing with the fun topic of making batteries from household materials.

Ahhh.... the old Web that I remember.

Too true, although for those of us a bit older, the 2009 web that this comes from is already so improved with its many differences from the "old old" web that we remember (yet still so much better than the web today).

Love it. Web pages like this are what the old Internet used to be. A dying breed now though.

If you're interested in DIY repairable batteries for e-bikes, check what we're building with engineers and designers from France at https://get.gouach.com :)

As much as I like your product, your message feels a bit too close to marketing spam in my book and I'd rather not have the HN comment section becoming full of such posts.

Keep up the good work though!

We're trying to get the word out around people interested in batteries, that's why I kept it as light as possible, just so that people can learn about it and see if they're interested! :)

IMHO posts like this one are too much, but when you do it like that[0] instead then it's OK to me.

For the record I vouched for your post above anyway, but if you keep doing that you'll likely get shadow-banned for spam so I think you really shouldn't be too heavy handed on self-promotion.

[0]: https://news.ycombinator.com/item?id=42504991

I agree. I think it’s the ‘if you’re interested in …, check out …’ pattern that sets off many spam detectors — including the one built into my brain. Without that, it’s already more palatable.

This looks really neat, I'm curious if you know if it's possible to get a UN and UL certified battery for some of the upcoming regulations requiring that in certain states, given that someone can open it up and swap out the cells?

We are in the process of UL-certifying it with the cells that we ship it with, then if you replace the cells, I guess the certification is not valid anymore, but if you choose good quality cells you should be quite reassured to know that the whole battery (except your new cells) has been certified, and that the casing is fireproof!

Reply on news.ycombinator.com