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Why can't EV's be self charging?

This topic can be found at:
https://sigforum.com/eve/forums/a/tpc/f/320601935/m/2990006715

October 07, 2025, 07:44 PM
kkina
Why can't EV's be self charging?
Perhaps we're being too hasty. This fella seems to have taken a step in that direction. Haven't watched the whole video, but I would not have expected this to work, at least not well. However, that is a pretty lightweight frame, so not sure if at all practicable for common consumer use.





ACCU-STRUT FOR MINI-14
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October 07, 2025, 07:48 PM
1s1k
quote:
Originally posted by kkina:
Perhaps we're being too hasty. This fella seems to have taken a step in that direction. Haven't watched the whole video, but I would not have expected this to work, at least not well. However, that is a pretty lightweight frame, so not sure if practicable for common consumer use.

[FLASH_VIDEO]<iframe frameborder="0" height="315" src="https://www.youtube.com/embed/qPENum9DFFA?si=DleSjgtiz2iPfo2G" title="YouTube video player" width="560"></iframe>[/FLASH_VIDEO]


I guarantee at highway speed that would produce more drag that would require more energy to push the car down the highway than it puts into the battery even with that lightweight vehicle.
October 07, 2025, 08:00 PM
wrightd
Para's correct. (battery stored energy) = (work moving the vehicle to your destination) + (heat generated by the vehicle) + (environment disturbed by absorbing energy of the vehicle moving down the highway etc) + (other types of energy described by physicists) etc.

Plug it in, energy is transferred from fossil fuels, wind, water, solar etc. into the battery as stored energy, then transferred (released) as per above when you drive to work the next day. An endless cycle.

Energy from the earth is diffused via entropy into space never to return again, replaced again by the Sun's light energy escaping to earth (the Sun's entropy) which recharges the earth with energy transferred into the atmosphere, trees, the ocean, your skin via conduction, convection etc. (so you won't freeze to death), an endless cycle of energy transfer, but the total amount of energy in the universe remains the same (with the possible exception of mysterious dark energy, a theoretical and unknown but measurable quantity.

Best explained by a physicist of course. Listen to some podcasts about entropy, it's not always in one direction at the macroscopic level. Fascinating stuff.




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October 07, 2025, 09:04 PM
Orguss




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October 07, 2025, 09:28 PM
arcwelder
There is no free lunch. EVs can "self charge" with regenerative braking or if there are panels.

For local commuting, they work fine. For a work vehicle or hauling? Fuck off.

THE solution is actually hybrids like my wifes Subaru. I drive a Leaf on my daily commute now that I'm not driving a van full of tools and materials.

Going "all electric" is a a fools errand, if every home and vehicle were electric, not only would the grid be fucked but we'd all enjoy the govt telling us when to turn our power on and off.

I've had solar panels on my home for years, and do embrace energy efficiency.

But mandating it? Fuck yourself. The cart is still waaaaaaaaay before the horse if you want to require all electric.

Save the planet. Kill yourself.


Arc.
______________________________
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Rode hard, put away wet. RIP JHM
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October 07, 2025, 09:40 PM
kkina
Reminds me of people who think you can have a source of free energy if you use a one horsepower motor to drive a two horsepower generator. You get double the energy you put in! What, you can't turn a 2 HP gen with a 1 HP motor? You forget about mechanical advantage: use gears or pulleys to make it run.

Long answer: extended lecture on the Laws of Thermodynamics.

Short answer: a 1 HP motor cannot turn a 2 HP generator fast enough for it to achieve rated output.



ACCU-STRUT FOR MINI-14
"Pen & Sword as one."
October 07, 2025, 09:51 PM
parabellum
quote:
Originally posted by arcwelder:
Fuck yourself.
Who are you talking to? Tell me. Are you you spewing this angry horseshit at someone in this thread, or are you just derailing a technical discussion with unwelcome political commentary? Tell me. I want an answer from you, and if you want to retain your posting rights in this forum, I'll have it.

I've had it with you showing up, crapping in threads and insulting forum members, disappearing for weeks, then showing up and doing it all over again.

Speak up. Put the scotch down long enough to respond.
October 07, 2025, 10:57 PM
arcwelder
quote:
Originally posted by parabellum:
quote:
Originally posted by arcwelder:
Fuck yourself.
Who are you talking to? Tell me. Are you you spewing this angry horseshit at someone in this thread, or are you just derailing a technical discussion with unwelcome political commentary? Tell me. I want an answer from you, and if you want to retain your posting rights in this forum, I'll have it.

I've had it with you showing up, crapping in threads and insulting forum members, disappearing for weeks, then showing up and doing it all over again.

Speak up. Put the scotch down long enough to respond.


Apologies, I've long been to blunt. People who think electricity is a panacea, and that we should dismiss natural gas and other means are very shortsighted. The average electric home now demands 400 amps or more.

Electric cars have their place, and are a net positive properly applied.


Arc.
______________________________
"Like a bitter weed, I'm a bad seed"- Johnny Cash
"I'm a loner, Dottie. A rebel." - Pee Wee Herman
Rode hard, put away wet. RIP JHM
"You're a junkyard dog." - Lupe Flores. RIP

October 08, 2025, 05:31 AM
Georgeair
quote:
Originally posted by old rugged cross:
I am not saying solar is answer but what if solar tech. advances, which it will. You guys are stuck in the past and the current.

Well, the sun's intensity would have to increase to the point it stripped the atmosphere and your skin for this to work. I'll just stick to other options for now....

Not saying there's not another power option down the road, but it's not the current battery tech with a "better" recharging method.

Perhaps your framing around current EV technology is what's stuck....



You only have integrity once. - imprezaguy02

October 08, 2025, 06:01 AM
snidera
Easy answer is 'Math, Physics, Thermodynamics'.

Wind generated by driving won't work - drag, friction & conversion losses will always make the net less than required. It's a simple 'perpetual motion machine'. The examples & math are a lot harder to visualize & explain, so I'm not going to try.

If you average the sunlight hitting the earth, you get about 340W/m2 - that's average over time. If we ignore the night, it's about 1.3kW/m2
I'm going to say a car is 2mx8m = 16m2.
That's 20.8kW max during the day & 100% efficiency.
Current Solar panels are ~20% efficient at peak. 25% takes some voodoo & lies.
Ignoring any conversion loss & using the generated power ONLY to drive the wheels, you'll get 4.16kW @20%. That's about 5.5Hp. If you're driving pushing a lawn mower, that's probably enough, if the grass ain't thick.
Even at 5x, which get's you to 100% efficient Sun>Drive, you looking at motorcycle power in a large car, with no A/C, Heat, radio, etc. At least you wouldn't need lights, cause it wouldn't run at night.

Panel based solar farms are a stupid idea a well, but when stupid people make decisions.......
October 08, 2025, 06:26 AM
BurtonRW
quote:
Originally posted by nhracecraft:
Dilithium Crystals...Just sayin' Razz


Yeah, but then you have to store the antimatter onboard. Also, you’d have every shade tree mechanic messing with the intermix ratios thinking they can make something other than 1:1 work and then you’d have antimatter explosions taking out neighborhoods all over the place.

Bad idea.

-Rob




I predict that there will be many suggestions and statements about the law made here, and some of them will be spectacularly wrong. - jhe888

A=A
October 08, 2025, 07:35 AM
myrottiety
About the closest we'll ever get. If having a little arm that plugs in the car for you. But while in movement as others have said. It's just impossible.




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October 08, 2025, 08:33 AM
BigSwede
With the Gov't subsidies gone, they will have to get much cheaper for folks to buy them in large quantities. Pretty sure $100k Hummers and trucks will be gone soon.

The Volt was self charging, it was a cool design. It had a small four cylinder that ran a generator when the battery was low on charge, if you had gas in it you didn't have to stop for a recharge


October 08, 2025, 08:55 AM
Perception
The main issue is that EVs use a HUGE AMOUNT of power. I think the smallest Tesla battery these days is >55 KWh. They already do use regenerative braking, but that's only putting a few watts back in the system here and there when you're taking hundreds out every mile you drive.

Adding an alternator, generator, wind turbine, or any other device would use more energy than it generated by a wide margin.

If you covered the entire surface of the car with solar you would probably only get a thousand watts or so. You're talking weeks of real world production to fill the battery, and that's discounting the extra energy you would use every day to carry around the solar panels. Solar technology is a long way away from being efficient enough to provide benefit here.




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"Odd," said Arthur, "I thought you said it was a democracy."
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"Oh yes," said Ford with a shrug, "of course."
"But," said Arthur, going for the big one again, "why?"
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October 08, 2025, 09:07 AM
IndianaBoy
quote:
Originally posted by old rugged cross:
It cannot be that difficult. The tech has to be there and cannot be that expensive to produce. Whats the hold up?


You are asking for a perpetual motion machine. The laws of thermodynamics can not be refuted.

Regenerative braking can help to a small extent.
October 08, 2025, 09:09 AM
IndianaBoy
quote:
Originally posted by WaterburyBob:
You're basically asking for a perpetual motion machine - which is impossible due to the laws of thermodynamics.

Power derived from air flow will lose a portion to friction.
The energy gained from any means must always be less than the output of the device providing it.



I made my post before I scrolled through the thread. We might be twins.
October 08, 2025, 09:43 AM
egregore






"The Almighty, He put some livin' things on this earth so a man can eat." - Festus Haggen, Gunsmoke
October 08, 2025, 09:59 AM
ss9961
What about the laws of thermodynamics?
How is it possible that nobody has mentioned
the laws of thermodynamics?

Seriously guys. You’re all forgetting the laws of thermodynamics.
October 08, 2025, 10:01 AM
smlsig
Each year some of the brightest engineering minds in the world develop a state of the art car to compete in a solar car race.

I find it extremely interesting but as you can find out we are not there yet…

https://worldsolarchallenge.org/


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October 08, 2025, 10:04 AM
V-Tail




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