People: cry how we are in an energy crysis, how expensive Li batteries are, how expensive and scarse are the resources and how wasteful the production process is

also people: pop 500mAh Li batteries in disposable e-cigs that get tossed away in the streets with ~75% of the charge left

me: picks those e-cigs, takes the batteries out, solders them in parallel and makes a proper powerbank for free

@chatgpt why are Li batteries standardised at 3.7V and not some other potential? Why not 3V or 4V? Or even better - 5V, considering that 5V is also a popular DC standard (USB)?

Also, why aren't 5V batteries a popular standard? Wouldn't they make more sense than 3.7V?

@netikras
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@electrineer ggwp ^^ 😁

I think the voltage comes from the chemistry itself

gathered a bunch of those, that was my plan too lol 😅

e-cigs addicts. So convinced they are healthier than regular smokers and their vice is therefore a-ok and they can just go crazy with it. So dumb

@nitnip I smoked electric a few years before it was cool. Reason electric smokers do it so much is because you can't get sick on it like cigarettes. After three cigarettes you'll feel sick. Also, I'm sure it's "healthier". My body tells me

Everyone is doing cool stuff like picking up e-cigarettes. What am I doing with my life..

@retoor how healthy it is depends on what the liquid contains. If you're not in control, it can contain all kinds of crap that's not necessarily less bad than smoking.

"makes a proper powerbank for free"

While i'm a huge fan of diy and used to have urges to salvage everything, i'm not sure what your time costs are. Picking up ecigs across city, disassembly, capacity testing and final assembly consumes time and looking at my hourly rate, that time is not "free".

We don't even have to speak about money. "Personal time" is a finite resource. So while it's nice to salvage and recycle, you still had to "pay" for it just not with $$$.

Have you seen the disposable powerbank yet? Its a LiPo battery that gives your phone like 20-30% charge then you throw it away. Just search "power hit disposable charger" and feel the waste!

@qwwerty buying a power bank waste your time as well. If you build a lot of power banks, the time you spend may be quite equal doing them yourself. Using these cells for your unique projects you can't buy anywhere makes more sense though.

@qwwerty I've stopped evaluating everything in $s a while ago.

Also, DIY is fun

@electrineer if you can gather parts (10 Ah = 20x 0.5 Ah ecig), do all the testing, and assembly an operational powerbank in the same time it takes to order it online and pick it up once it arrives, then i honestly admire your diy skills.

@netikras see last paragraph. you can drop $$$ and evalute it in "time available to do anything else". it still has a price and does not come "free"

@galena it's OK. There is an recycle logo on it

@qwwerty as I said, if you build a lot of power banks. For a single unit, it doesn't work out, especially since you don't need to find the best one to buy since it's just a single unit.

If you build things for fun, the time spent is on the benefit side, not the cost side. Do you go to the movies only if someone pays you?

@electrineer

a) i don't go to movies.

b) you missed my point. i'm not saying somebody is supposed to pay you money. I'm just alergic to saying "it's free" when you have to pay with a limited resource (your time)

@qwwerty
a) That was a rhetoric question, but I wouldn't take you to one even if it was free.

b) Yeah, technically it's not free in that sense but it pays you. Think of it as free entertainment.

@qwwerty You know what I meant and you know it :)

quit searching for earthworm's pubes

as elly said, batteries are not "standardized" it's just the chemistry behind it.

Every element has it's own chemical potential (usually normalized with Hydrogen at 0V). So when you take 2 elements to form a battery you just add those 2 numbers and get that voltage

There it is:

https://en.wikipedia.org/wiki/...#Table_of_standard_electrode_potentials

that being said you could design a battery to exactly fit 5V.
However as we all know there are plenty of other design goals to be met currently so I guess the exact voltage is more a result than a choice

E.g. I got some AAA rechargeable batteries (Ni-MH) that only got 1.2V instead of the classic 1.5V that the alkalines had. They still work in most devices.

@Jedidja alkaline batteries can be considered empty when their voltage is at 0.9 V. If a device doesn't work with a fully charged NiMh cell, it means that it's leaving maybe over 20% of the energy in alkaline batteries unused.