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Comment by Reason077 | Hacker News Reader

> “even if we were to completely stop mining for and using lead (which we aren’t, since the lead-acid battery market is projected to increase in the next years”

I’m surprised by this. Modern cars (EVs, at least) have started replacing their 12V lead batteries with Li-ion, which are more durable, store much more energy, and of course are less toxic.

But in any case, isn’t the one advantage of lead-acid batteries their recyclability? Don’t 99%+ of lead batteries get recycled into new lead batteries?

Surely there can’t be all that much new lead being mined for batteries?

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Most EVs have a 12V lead acid battery for standby power and to buffer the 12V accessory system. The solenoids to the traction battery are open when parked and the 12V battery closes them when the car is started.

This does mean you might actually need a “jump start” for an EV if the 12V battery is drained, eg from leaving a light on or a fault in the 12V charging system.

Yes, EVs still have a 12V battery, but it’s not always lead acid. Tesla, for example, switched from lead acid to Li-ion 12V batteries in all their models several years ago. So have Porsche, even in combustion models I believe.

They are a lot more expensive though, at least aftermarket.

Yes but you have to replace them much less often. Kind of like LED vs incandescent light bulbs.

True - they're also lighter.

I assume that jump starting an EV takes a lot less current than jump starting an ICE due to no need to crank an engine. I'd guess it just needs enough to power the control electronics and close the solenoids to the traction battery?

That raises an interesting question: is the power requirement low enough that you could make a hand cranked EV jump starter?

You would be correct.

It needs enough to open the contactors which allows the high voltage battery to send power via the inverter to charge the 12V

My Lithium Ion jump pack is tiny, about the size of two iphones stacked on top of each other, and a single jump uses only a few %.

Back to crank starting a car? We have come full circle.

That's because everything in a car is standardized into 12V, but the EV engine run on some hundreds of Volts. It would be dangerous to feed energy from the engine's battery into the rest of the car.

As a sibling said, that doesn't require that you use a lead battery. The only requirement is that it's insulated from the main one.

The lead batteries have always be 90%+ recycled (well, at least since any time we should care about). So the amount of mining is still proportional to the amount of batteries running around.

Right. The recycling rate is around 99%, apparently. So the number of lead batteries running around only has to shrink by 1% per year before we don't need to mine any new lead for batteries. Something that seems likely to happen in the coming years as EVs become dominant and Li-ion gets cheaper.

86% of lead being mined is for batteries. I just replaced my UPS battery, and their shop was stacked high with UPS devices and battery packs and it was a real reminder to the massive amount of batteries out there.

So data centres and edge compute UPS devices. Something has to keep the lights on when the power goes out while the generator kicks in. While the lead is recyclable, the power demand keeps going up. So my guess is AI…

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