I know I am just an old mechanical designer who knows close to nothing about electricity but why can't an electric vehicle charge itself? Gen sets can charge batteries, which most are just diesel engines turning a generator that produces electricity, seems as simple to me as hooking a generator to the rotating mass that the electric motors run? Is it that there is just no profit in it? Discuss...

Because it takes power to make power. Use power to keep the batteries charged and you don't have any left to power the car.

this is inaccurate in regards to a hybrid. They have enough power to charge the batteries and keep the car running down the highway. Speed limit is 75 around here and that Escape had no issue doing it.

https://en.wikipedia.org/wiki/Ford_Escape#Hybrid

If you are referring to a pure electric vehicle, then the best way to keep those batteries charged is to not drive it.

When electric motors and generators were invented/discovered, many people thought it would result in a perpetual motion machine. It doesn't work that way. if you're using an electric motor to run a generator, you lose power due to the resistance of the wiring and connections, without even trying to draw power off to do anything extra like power a vehicle.

When I ran the municipal garage, I was trying to get a test program going with my city, Mack, and Parker hydraulics for Hydraulic Launch Assist for refuse trucks. Residential refuse trucks have a crazy duty cycle: from a dead stop, accelerate at WOT for about 70', then stand on the brakes for 50' to get to the next bin. if you install a hydraulic pump/motor in the driveline and use it as a pump to charge an accumulator during braking to store the energy (fluid under pressure), then release that energy to drive the motor during acceleration, you theoretically can use a smaller engine to power the truck, use less fuel, etc. Sounds great, right? There's a similar system for city busses, but the duty cycle on refuse trucks means by pressurizing the fluid you increase it's temperature as well, and when you do it 500 times a day, your fluid overheats in about 100 stops. You end up with a HUGE reservoir and cooler for the fluid, to prevent that, and the weight of all of that equipment and fluid eats up any benefit of the system.

The bottom line is that gasoline and diesel fuel became the common motor vehicle fuels through a Darwinian process that began in the late 1800's. They are (relatively) stable, can be stored at common atmospheric temperatures and pressures (in quantities from small to huge), allow for refueling with VERY minimal training and no protective equipment, and became available essentially worldwide. EVERY alternative has significant drawbacks in at least one of those areas. You can argue that gasoline is a fire hazard, but it's (again relatively) easy to extinguish. Look at the reports on the wrecked Tesla that took over 4 hours to drown (literally) after it sat untouched in a junkyard. Forget your gloves when refusing your propane vehicle and you can lose a hand to frostbite (imagine letting your 16-year-old kid try it on their own). CNG vehicles require complete purging of the pressure tank before any maintenance work is done, OR a completely explosion-free shop be constructed with enclosed electrical systems, no spark-producing tools, etc. Hydrogen shows the most promise but again the technology is not yet mature enough for mass production.

IN MY OPINION, the move away from fossil fuels is another example of politicians trying to legislate technology. They want what they want (and WHY is a different discussion) without concern that it's not practical in today's world.

I know I am just an old mechanical designer who knows close to nothing about electricity but why can't an electric vehicle charge itself?

Some automakers plan to put on board generators as "range extenders" to burn gas to recharge the batteries.

"Some automakers, including BMW, are producing electric vehicles with internal combustion “range extenders.” These are essentially efficient generators that can burn gasoline to replenish the battery while on the road. Ram may be eyeing a similar setup for future vehicles."


https://www.motorbiscuit.com/heres-everything-we-know-about-the-electric-ram-pickup-truck/

I look forward to future "range extender" jokes...

I would have thought that would have been in Engineering 101 !!! You can't get more energy out than you put in. HOWEVER, consider that electric motors are also generators. While the motor is used to propel the vehicle, it can generate power when used as a brake or when coasting down a hill. So, if you were going for a long drive and it was all downhill, the vehicle could charge itself. However it would not generate sufficient enegy to make the full uphill return trip

Electricity is a funny demon. But like the old saying goes: "There's no such thing as a free lunch." Power (or "energy") is ALWAYS lost through friction, heat, resistance, etc.
You'll never get MORE out of what you put in.

A fun experiment is to get a cheapy little 40-amp alternator. Hook it up to a battery source and a regulator and now YOU try to turn that alternator. You might be able to; but not sustainably enough to be useful.
Now, get a 200-amp alternator from a big truck and do the same thing. A small team of dogs wouldn't be able to turn it. You would need the mass of something; like a car - to be able to turn that sucker.

Lots of the electric things have regenerative braking - and this is a wonderful thing. But you can't have it ON all the time - the drag would be immense and you'd be wasting 10x more energy trying to get something out of it.

Why don't race cars have alternators? It's not because they don't have headlights! It's because that little chargin' whirler saps up an easy 5hp. The bigger the alternator, the more hp it takes away!


Personally, I think we should be looking more into Hybrid/Turbine technology. A small Turbine powerplant that has three states: OFF, idle or RUN and therefore can be tuned to run as cleanly as possible. It's only job is to turn a generator that can power an electric motor and maybe a small, backup battery. A multi-fuel Turbine would not only be able to run off of ANY combustible fuel, it can be tuned to run as cleanly or cleaner than any current internal combustion engine; but it's maintenance now drops to ZERO and moving parts/failure rate plummets. Win-Win for the consumer; not so much for the manufacturer.

But I also think we've gotten away from simple reliability. I firmly believe ALL electric cars should have a simple, planetary transmission. Why? Very Simple. A "classic" three-speed or even 2-speed transmission would:

Provide a "PARKing" position that everybody and their dog is used to.
A much simpler reverse function - rather than reversing the electric motor (which requires big, heavy circuit breakers and relays) - just do it hydraulically.
A NEUTRAL position for pushing/towing that not all electrics have!!
Drive for every day driving.
Gear reduction should such an idea be necessary.

But, the other great thing about a simple transmission would be it's fluid pump. I don't think it would be much parasitic loss to have that same pump power a hydraulic power steering unit and a hydroboost brake unit. We could also plumb a heater matrix into the fluid system because the fluid will get warm. Why not dissipate that heat through the cabin rather than have 39 separate electric systems doing all these jobs.

I really think the designers of today believe themselves to be much smarter than they actually are. None of them have ever heard of the phrase "Putting the cart before the horse." They've no idea what a cart nor a horse is.

hydraulic power steering unit and a hydroboost brake unit.

Get congress to change the first and second law of thermodynamics and you're all set. It should not be too hard to find some congress men or women to sponsor that bill. They just haven't thought of it yet.

Why don't race cars have alternators? It's not because they don't have headlights! It's because that little chargin' whirler saps up an easy 5hp. The bigger the alternator, the more hp it takes away!

An alternator isn't an on/off device, properly setup it only puts out enough to maintain system voltage. If the load only calls for 20A of charging current then that is all any alternator will put out 40A or 200A. There is an argument to be made that having a stable system voltage provides for a more consistent ignition system and a more consistent run. It would be more accurate to say the more load there is the more hp it takes to turn the alternator.

That said, the reason drag racers don't run an alternator is more for weight savings. As little as they stress the battery between rounds is what allows them to get away with it. You'll note they charge the battery between each round, or damned well better.

That is the only application I can think of that allows for running without an alternator.

but think of all those battery companies and lithium mines

i was looking for a reason to post this

https://www.youtube.com/watch?v=wW7J2DkRaO0

it cant charge itself but WHO CARES!!!!!!!!!

Keep in mind that both of these would add a tremendous amount of weight over the current electric power brakes and steering - not to mention the power loss of driving them. I'm pretty certain they consume less electrical energy than would be needed to run hydraulic units. Keep in mind also that unless the motor is turning, these would have no power whereas the electric units do.

I know I am just an old mechanical designer who knows close to nothing about electricity but why can't an electric vehicle charge itself? Gen sets can charge batteries, which most are just diesel engines turning a generator that produces electricity, seems as simple to me as hooking a generator to the rotating mass that the electric motors run? Is it that there is just no profit in it? Discuss...

Because if an electric car could create enough power to propel itself indefinitely you would have created perpetual motion for the first time in the history of the world. Newton says that can't be possible.

I am not asking for perpetual motion, just add a couple alternators to give extended range! Racers have been putting pulley's on driveshafts for years hanging an alternator close the the rear end, so any rotating member could be used to put on a pulley and hang an alternator somewhere...

What would that accomplish? What do you think is driving those alternators? Besides, the battery pack requires a heck of a lot more voltage than any alternator you might hang on a driveshaft, or wherever.

EV's already use regenerative braking to recoup energy to some extent. Read up on that because it sounds like you don't know what that is. At any other time the motor is driving things and all you are doing is wasting more power than you could recoup driving something to charge the batteries. Anytime energy changes state (electricity to mechanical, or mechanical to electricity) you have conversion losses. It the cost of doing the conversion. What the percentage of energy is lost is varies depending on how efficient the device is but absolutely zero of the them are 100% efficient. So you lose just in the conversions involved and you'd end up with worse mileage than you started with.

Even if you could make them 100% efficient you'd have a wash, same in as out. You'd have to be more than 100% efficient to gain anything and that's perpetual motion.

I know what regenerative braking is, known it for decades. Posts like yours just say "nothing can be done" and leaves it at that. I am asking for a paradigm shift in thinking, so what you are saying is that there is no reason to even try. ANY help keeping the batteries charged is better than just saying "it won't work"...

I didn't say nothing can be done. I said your idea can't be done successfully. Multiple people have told you it won't work, it violates the laws of physics no matter how hard you roll your eyes.

You want to do something to charge an EV while it's in use? Put solar panels on it, mind the aerodynamics. Get one of those old WWII hand crank generators and get your cardio while you are at it.

Ultimately, the only idea I have heard that might be actually functional and not pie in the sky "I don't know what I am talking about but it sure sounds good listening to me talk" thinking is a wireless charging system imbedded in the roads. No idea on cost effectiveness or charging efficiency.

I talked about the road charging earlier. I just figured there are a few smart people here on the board who might think beyond "the law of physics". Those laws only apply on this planet I am pretty sure...

I talked about the road charging earlier. I just figured there are a few smart people here on the board who might think beyond "the law of physics". Those laws only apply on this planet I am pretty sure...