Lithium battery costs have fallen by 98% in three decades • Hacker News Board

Re: Lithium battery costs have fallen by 98% in three decades

#411

Post by mlindner » Mon, Apr 05, 2021, 2:42 AM UTC

vkou wrote: post #353

mlindner wrote: post #191

Earlier quoted context omitted.

> So, this is about to stop. Very soon. Quantum tunneling, yield rates, etc are all starting to be cost prohibitive. People have been saying that for over 10 years though. "Very soon" keeps being punted off by another 5 years every 5 years.

It has stopped, though. Single-threaded performance, either in absolute value, or per dollar has not been following Moore's law for more than a decade. And outside of data centers, single-thread performance is still king. Performance per watt has improved, but that's not a metric the typical end user cares much about.

Single-thread performance is not king though. Software nowadays is extensively multi-threaded. If you're still writing single threaded code for a desktop program people are going to look at you like you have antenna growing out of your head.

And performance per watt absolutely is important. People care a lot about battery life of their laptops and phones and that's strongly dependent on performance per watt.

Re: Lithium battery costs have fallen by 98% in three decades

#412

Post by elihu » Mon, Apr 05, 2021, 4:17 AM UTC

yellowapple wrote: post #365

elihu wrote: post #342

Earlier quoted context omitted.

The other way that EVs enter the market is that someone takes a gas-powered car and converts it to electric. It's not a particularly common thing to do, for multiple reasons. It's time consuming, expensive, and requires tools and space, and a certain amount of expertise or willingness to learn. The may be a lot of people who have the time, inclination, space, and access to tools to do a conversion but are blocked by…

There's also a bit of an annoyance w/ EV conversions, at least here in the US: automatic transmissions being pretty much ubiquitous. They're basically dead weight for an EV (which doesn't need to switch gears), and they further tend to have a lot of mechanical and electrical complexity. I suspect that if I ever convert my Highlander to an EV (which is something I'd like to investigate should its current drivetrain ev…

Transmissions aren't entirely dead weight; being able to switch gears means you can get away with using a smaller motor than you otherwise would. You also don't need to worry quite so much about getting a motor rated for super high RPM.

Converting something with a manual is probably easier than an automatic (especially if there's some software controlling when to shift the automatic based on some engine sensors which aren't there anymore), but there's no fundamental reason why you couldn't just keep the transmission even in an automatic. Especially if bolting a motor on where the engine was is far simpler than re-engineering half the drive train. (You might be able to get rid of or disable the torque converter, though.)

At this point I think the biggest roadblocks to EV conversion are cost and availability of parts so you don't have to design and build everything from scratch. And I think subsidizing conversions would help with both of these. If there's a big enough market, you might even get reasonably priced kits (possibly from the original vehicle manufacturer) that has everything you need including battery boxes and can be installed by someone who's done it before in less than a week.

(Battery boxes are usually the most difficult and time consuming part of a conversion, since they're usually constructed in an ad-hoc way to fit whatever battery you're using into wherever they would fit. Having something that's actually engineered and possibly even crash tested would be great.)

Re: Lithium battery costs have fallen by 98% in three decades

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Post by bdcravens » Mon, Apr 05, 2021, 4:57 AM UTC

Shivetya wrote: post #226

bdcravens wrote: post #180

Today I bought a new lawn mower, weed eater, and blower, all electric, with batteries, for less than $600 total (not even the cheapest models). They have comparable power to gas-driven models.

Just be sure when using a electric mower you opt for the higher amp batteries. They are also far more limited by wet or tall grass and heaven forbid trying both at once. Many push mowers will come with a 4amp or higher battery while blowers, weed eaters, and such, use 2 to 2.5amp battery. While the lower amp batteries can work in the mower they will heat up faster and may actually stop if the load they are put under…

Yes, I shied away from the lowest models. The mower is 6A; the weed eater and blower uses 4A.

Re: Lithium battery costs have fallen by 98% in three decades

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Post by dzhiurgis » Mon, Apr 05, 2021, 7:16 AM UTC

xedeon wrote: post #357

dzhiurgis wrote: post #200

Earlier quoted context omitted.

How do you people leave out ESC - it saved my life at least once or twice and it’s obvious how well they work. What leaves me even more fumbled is how easily RWD Tesla’s spin out and crash with regen and snow. Take the gas pedal of and you’re going off roading. With normal car you’d struggle to even trigger ESC, let alone loose it.

> What leaves me even more fumbled is how easily RWD Tesla’s spin out and crash with regen and snow. Where did you get this info from? This is contrary from everything that I've heard from my local Tesla owners group. To the point that they don't even have to swap to snow tires during winter. Some video examples: [1] https://youtu.be/v_bfRm5hGN4?t=203 [2] https://youtu.be/v_bfRm5hGN4?t=272 [3] https://www.youtube.com…

Have a look this guy videos - collected from crashed Teslas - https://mobile.twitter.com/greentheonly/status/1359639313424...

There’s more than one and obviously we don’t know the state of tyres, but even with bald ones seems any car with ESC should handle such manoeuvre...

Re: Lithium battery costs have fallen by 98% in three decades

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Post by jpalomaki » Mon, Apr 05, 2021, 8:00 AM UTC

gpm wrote: post #379

spookthesunset wrote: post #302

Earlier quoted context omitted.

I don’t think modern quads would be possible with combustion engines. They aren’t precise and responsive enough. Modern brushless motors paired with some pretty kickass electronic speed controllers and flight controllers create a pretty amazing thing. I mean modern quads can fly in “3D” mode and almost instantly reverse the direction of all the motors so the quad can fly in all orientations, right side up and upside…

Have the combustion engine drive a generator not the props, it's still more energy dense (but only scales so small).

I guess it's not just about the energy density, but also about how quickly you can convert the stored energy to kinetic energy. Maybe this is something where the modern batteries are much better and combustion engine/generator combo. Parent comment mentions being able to get 2000W out of those small batteries.

Re: Lithium battery costs have fallen by 98% in three decades

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Post by brtkdotse » Mon, Apr 05, 2021, 9:26 AM UTC

magicalhippo wrote: post #81

hannob wrote: post #31

Earlier quoted context omitted.

The US 10k kWh average is extremely high. The EU average is 3.7k kWh.

Here in Norway the average is 16k kWh a year[1], or about 44kWh a day, but then most uses electricity for heating, hot water etc and it gets fairly cold during winter. [1]: https://forbrukerguiden.no/normalt-stromforbruk/

Similar numbers for Sweden. Americans (actually most of the English speaking world) seems to be terrified of insulation.

Re: Lithium battery costs have fallen by 98% in three decades

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Post by sgt » Mon, Apr 05, 2021, 9:40 AM UTC

sjwright wrote: post #404

sgt wrote: post #400

Earlier quoted context omitted.

That's impressive. What's your usage pattern like? I mean, in our house there's regular use of washing machine, tumble dryer, dishwasher, TV's, swimming pool pump. Heck even the swimming pool takes a couple of kWh a day! Would be curious on how to live so frugally.

Sorry if I was unclear. 5 kWh/day of idle. That’s how much it uses when we’re literally not home and all I’ve left on is the networking gear, appliances on standby, etc. My average actual occupied usage is closer to 20-25 kWh/day, varying mainly by AC load.

Sorry, you were clear enough, I just didn't read properly. I think my idle is about the same.

Re: Lithium battery costs have fallen by 98% in three decades

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Post by CRConrad » Mon, Apr 05, 2021, 12:10 PM UTC

kragen wrote: post #34

dragosmocrii wrote: post #2

The article says that today a battery pack the size of a backpack and that weighs about 40kg, can power a house for a day. Is that really so? Would that be a normal house, being powered for an entire day? I find it hard to believe that battery would pack that much energy

https://en.wikipedia.org/wiki/Energy_density_Extended_Refere... lists "battery, Lithium ion" as 0.46–0.72 MJ/kg. : user@host:~; units 2529 units, 72 prefixes, 56 nonlinear units You have: 40 kg * 0.6 MJ/kg You want: MJ * 24 / 0.041666667 (The 13.5 kWh in 114 kg tyingq cites for a Powerwall 2 in https://news.ycombinator.com/item?id=26682770 works out to 0.43 MJ/kg, which includes some power electronics as well as the…

> The article claims that in the early 01990s this quantity of batteries would have cost US$75k.

Oh come on, isn't that wildly overdoing it? We have almost eight thousand years to go before the fifth digit becomes necessary!

Re: Lithium battery costs have fallen by 98% in three decades

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Post by jodrellblank » Mon, Apr 05, 2021, 6:44 PM UTC

sandworm101 wrote: post #344

will4274 wrote: post #298

Earlier quoted context omitted.

It's about mature and immature technologies. 20 years ago, photovoltaic cells had efficiency ranges in the single digits, but rising. When efficiency rises from 5% to 10%, it makes sense to assume that it keeps rising. But electric heaters had efficiency ranges around 95%, even when my parents were kids. Now they have even better efficiency - 99.8% in my newest apartment - which is only 5% better than 50 years ago -…

Any electric heater, even those decades ago, was 100% efficient. They turn electricity watts into heat watts. Where is the energy loss? Light? That also becomes heat. Air movement? Also heat. Loss due to heat allong the cord to the heater? Thats heat too. Unless they are emitting large numbers of neutrinos, all electric heaters are simply resistors that perfectly turn electricity into heat. Put nearly any electrical…

You can't have a wind turbine which extracts 100% of the kinetic energy from wind, because after it there would be a wall of unmoving air, and the incoming air wouldn't be able to get through the turbine.

Analogously, if electricity is carried with the flow of charge - electrons - around a circuit[1], when you extract 100% of the energy as heat, the electrons stop moving and build up in the heater. So you can take the rest of the wiring away because it's doing nothing and save 50% of your costs. Then, a buildup of charge makes a voltage, and a voltage potential difference can drive a current. Therefore you can get 100% of the power out as heat, save half your money on wiring, and use the growing potential difference to power something else. Electricity makes no sense whatsoever.

OK, so that's troll-physics nonsense, but does extracting all the "energy" stop the electrons moving? If not, why not, what energy isn't being extracted? If so, why doesn't that stop current flowing - isn't "free electrons" part of what makes something a conductor of electricity?

[1] though the energy is carried in the e/m field around the surface, somehow

Re: Lithium battery costs have fallen by 98% in three decades

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Post by jjk166 » Mon, Apr 05, 2021, 8:05 PM UTC

jpalomaki wrote: post #415

gpm wrote: post #379

Earlier quoted context omitted.

Have the combustion engine drive a generator not the props, it's still more energy dense (but only scales so small).

I guess it's not just about the energy density, but also about how quickly you can convert the stored energy to kinetic energy. Maybe this is something where the modern batteries are much better and combustion engine/generator combo. Parent comment mentions being able to get 2000W out of those small batteries.

Combustion engines have much higher power densities than batteries