Engine alternatives

[Bones]

I'll admit I'm not the sharpest tool in the shed, but concerning battery range why can't they just fit high output alternators to each wheel to charge the battery while driving. You hear about battery regeneration while braking so what's so hard about doing the same while driving, that way theoretically you would have endless range.

[Motofun]

I'll admit I'm not the sharpest tool in the shed, but concerning battery range why can't they just fit high output alternators to each wheel to charge the battery while driving. You hear about battery regeneration while braking so what's so hard about doing the same while driving, that way theoretically you would have endless range.

I like the way you think!......

[red]

I'll admit I'm not the sharpest tool in the shed, but concerning battery range why can't they just fit high output alternators to each wheel to charge the battery while driving. You hear about battery regeneration while braking so what's so hard about doing the same while driving, that way theoretically you would have endless range.

Bones,

It takes power to move the vehicle forward.  It takes power to turn an alternator.  No alternator can produce as much power as it takes to turn it.  You can put in ten Watts of rotational energy, but you can only get eight Watts out as electricity. (as an example).  Your idea would be like putting an airplane engine on a square-rigged sailing ship, to blow wind into the sails.  Net result, the ship goes nowhere.

Normal braking uses friction to convert forward motion into heat, which is then wasted - we have no way to capture and use that heat.  In fact, we need that heat to go away (dissipate) quickly, so the brakes do not get too hot to be used again.  When an EV needs to stop, we can use the wheel motors as generators (alternators) to make the rotational energy at the wheels back into electricity, instead of wasted brake heat.  That is regenerative braking.  Now if it takes 100 Watts to make the vehicle go, you can only get maybe 80 Watts of electricity back in the stopping.  This trick can help to extend battery life, but you can never get out more power than you put in.  If you could, everybody would have cars that ran forever without adding any gasoline or electricity.

[gumby302ho]

 I talked to a guy that had a Chevy Volt, he said growing up he had all the hot rods like camaro and mustang and such and he said this little Volt out accelerated all of them. This was a short conversation so maybe they were stock units from factory and not had any power mods but these EV's do get up and dance. My take is that the glory days of the ICE need to be rendered obsolete if your great grankids and they're off spring still want to breath O2. I know it sucks and I am a gear head and love the piston engine but one thing constant in the universe is CHANGE. We cant keep following the same course. Next the meat eaters will be the enemy. I like a dam good steak.

[Ted Schefelbein]

For top level drag race applications, I wonder how hard it is to consistently control the output at launch and early acceleration?  How much does the actual output vary with battery temp, motor temp, charge level, etc?   
I also assume these "new tech" motors are AC vice DC?  How different are the controllers for AC vice DC?  I'll have to dig a bit to find it again, but I was following a DIY controller group for a while.  There was discussion of mods or changes for AC control - but don't remember details.

FJ1289,

I can imagine a traction control set-up for the launch sequence that would give consistent results.  With an accelerometer and wheel-spin detection, no human could perform better than the computer, on the launch.  You may want wheelie bars, though.
No doubt, the manufacturers will know what you need for speed controllers, for each motor.  Go with their recommendations for a start, until you know more about what is needed.

At that point, why involve a human? Make it autonomous, watch it run at the strip, but, ride an FJ to the strip.

Ted