Home » Those Darn Kids And Their Perpetual Motion Machines: COTD

Those Darn Kids And Their Perpetual Motion Machines: COTD

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There’s a meme going around the internet that people are buying into. The idea is that an EV will never need to be charged if you just bolted an alternator to its bumper and drove it from a rolling tire. It sounds great for a half-second before you remember that’s not how anything works.

Lewin wrote an excellent explainer about this subject today and it’s a great review of how thermodynamics works. Speaking of thermodynamics, multiple readers made the same joke today:

Vidframe Min Top
Vidframe Min Bottom

From Cranberry:

“In this house we respect the laws of thermodynamics!”

To TXJeepGuy:

Lisa, in this house we obey the laws of thermodynamics.

It’s a short, but awesome moment from a classic episode of The Simpsons:

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Another solid joke came from Snake_in_the_grass, which contains another good reference:

I’m not sure why you highlighted a turbo on that picture of an engine.

This morning, Jason wrote a Cold Start that’s nominally about pedal cars from Automobile Quarterly, but also about the creepy scenes of ventriloquist dummies in those pedal cars. Trenton Abernathy came out of left field with a good one:

Powered by VTEC (Very Tiny, Extra Creepy)

And now for something serious. I’m sure you’re well aware of how pretty much every major corporation in existence is trying to find new ways to get more money out of you. Video games are full of microtransactions and everything is a subscription service now. It seems like the future is owning nothing and being forced to be okay with it. Heck, United Airlines now wants to feed you a lot more ad content than usual, turning you into both the customer and the product. I feel Angel “the Cobra” Martin’s comment from the Morning Dump:

Monthly services for heated seats? I am supposed to pay a monthly fee for heated seats? Here is the issue. In the last month my health insurance has gone up 21.9% and my home owners insurance has gone up 102%. The rent at my shop is up 11.2% and business insurance is up 33.7%. Can I increase the cost to my customers by 25% in one blast? Well, I can, but they will be looking for another machine shop pretty fast. And now the auto industry wants to jam monthly fees onto the ownership cost. Something has to give, and I am tired of it being me.

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Have a great evening, everyone!

(Topshot: 20th Television Animation)

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Beater_civic
Beater_civic
21 days ago

What if your car had a tiny door that only opened for the really hot air molecules, but kept the cold ones inside? Perpetual motion and A/C achieved at the same time!

Coelacanth
Coelacanth
20 days ago
Reply to  Beater_civic

That’s Maxwell’s Demon: https://en.m.wikipedia.org/wiki/Maxwell%27s_demon

A classic thought experiment that connected thermodynamics and information theory.

Phuzz
Phuzz
19 days ago
Reply to  Coelacanth

You might have to rename it ‘Maxwell’s Dart Sport’ to sell it in the southern US though.

Cranberry
Cranberry
21 days ago

Bucket list item achieved, thank you quick but ever-so-slightly-off memory!

Farty McSprinkles
Farty McSprinkles
21 days ago

I am not sure if there has ever been a better show for quotable one liners than the Simpsons

Sammy B
Sammy B
21 days ago

The thermodynamics one is such peak Simpsons gold too. i remember watching this one live with my brother and dad (who is a chemical engineer). this line absolutely destroyed him. we’d always watch the simpsons together and he really enjoyed it. this one might be the one that got him the hardest in the first ~10 seasons.

Farty McSprinkles
Farty McSprinkles
21 days ago
Reply to  Sammy B

My favorite:
Bart: Nothing you say can upset us. We’re the MTV generation. We feel neither highs nor lows. Homer: Really? What’s that like?Lisa: Meh.

Scottingham
Scottingham
21 days ago
Reply to  Sammy B

They made more than 10 seasons of the Simpsons?

/s

Sammy B
Sammy B
20 days ago
Reply to  Scottingham

valid. it just sort of worked out that the three of us would watch up to season 8 together (when my brother left for college). then just my dad and me until I left for college after season 10. We’d watch together when we could of course (and I probably lasted as a “must watch every week” fan probably until about season 15-16), but the three of us all in the same house around the same TV was a core teen year memory for me 🙂 blessed that it happened to coincide with such awesomeness.

Snake_in_the_grass
Snake_in_the_grass
21 days ago

A nod from Mercedes! My soul can finally heal after being cemented in the greys for all those years…..

Peter d
Peter d
21 days ago

Good god, does no one pay any attention in High School Physics??

Also, to those that think you can throw some solar panels on the roof of your car and get free charging think about this – the most efficient solar panels produce about 300W per panel, this means that after an hour it will have generated 0.3 kW-hrs which is only enough to go less than 1 mile in most modern EVs. So to get say 20 miles of range in a 5-hour afternoon you would need 4 full sized panels assuming the sun is full and the battery charging system is super efficient – this doesn’t really give you much real-life range with a reasonable number of solar cells on your car.

As I am investigating PHEVs for my next car, I think I will need about 5 panels to fill up these batteries every night and not increase my electric power usage from the grid – and this is for batteries with ~20 kW-hr capacities, not your typical full BEV

Piston Slap Yo Mama
Piston Slap Yo Mama
21 days ago
Reply to  Peter d

My man, I’ve got your next ride right here, and wow is it a looker!

https://aptera.us/

CUlater
CUlater
21 days ago

Toecutter must be involved. 🙂

Tim R
Tim R
21 days ago
Reply to  Peter d

I would guess most of these people never took high school physics

Citrus
Citrus
21 days ago
Reply to  Peter d

I don’t know how well it actually worked but I did like the idea of the old Mazda 929 solar sunroof, that used the panels to power little fans to vent heat in the summer.

It feels like something that could actually reduce power use because it keeps the interior a bit less hot so you don’t have to blast AC the moment you get inside. If it worked well. I didn’t have a Mazda 929 so I don’t know if it did…

NewBalanceExtraWide
NewBalanceExtraWide
21 days ago
Reply to  Citrus

I used to have one that clipped onto the window- solar panels and little fans to vent out the hot air while parked. It worked remarkably well.

Peter d
Peter d
21 days ago
Reply to  Citrus

This, along with solar-powered battery tenders, are the correct use of solar on cars that roll around.

Ecsta C3PO
Ecsta C3PO
21 days ago
Reply to  Citrus

I didn’t know Mazda did it first.
The 2nd gen Prius (and maybe other years) works like this too if you have the solar roof option. Senses interior temperature and runs ventilation without AC. With the sunroof and the solar there isn’t actually any painted roof surface which is kind of cool

Chris D
Chris D
21 days ago
Reply to  Peter d

My solar panels can produce 370 watts, and they are almost two years old. 400+ watt panels are available now. However, that is the maximum, and they usually produce a maximum of about 320 watts, probably because they are never perfectly aligned with the sunlight angle, being affixed to the roof.
The only vehicles that can run off of solar panels are the bicycle-wheeled creations used in the annual Australian efficiency race, whose bodies are entirely covered in solar panels, and can carry one person.

Chris D
Chris D
21 days ago
Reply to  Peter d

The trick to creating a perpetual motion automobile is MORE GENERATORS – one would not be sufficient. One motor powering a couple dozen alternators would be more like it.

Ecsta C3PO
Ecsta C3PO
21 days ago
Reply to  Chris D

Only drive downhill and take a ferry to get you back up to the top

Lightning
Lightning
21 days ago
Reply to  Peter d

Sure, but think of what you can do if you can have college students build a car with a 0.095 cd, frontal area of 1.86 ft2, weight of 500kg, and solar array of 4.4 m2 that produces a car with an efficiency of 3.8kWh/100km on a 1,000km test in under 12 hours? The solar panels would be doing a substantial amount of work.

Phuzz
Phuzz
19 days ago
Reply to  Peter d

It is just possible to make a car that is powered only by it’s own solar panels, as shown by the World Solar Challenge, but the vehicles are very specialised and really stretch the definition of ‘car’.
Oh, and they only work when there’s sun.

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