New electric vehicles from Rivan

[Scout26]

So "Free Energy" ??   If you use the trailer to generate electricity, then you have to factor in resistance, friction, and battery charge loss.  In other words, you use more energy putting into the battery then you can get out latter.

https://batteryuniversity.com/

[dogmush]

So "Free Energy" ??   If you use the trailer to generate electricity, then you have to factor in resistance, friction, and battery charge loss.  In other words, you use more energy putting into the battery then you can get out latter.

https://batteryuniversity.com/

Almost as if the total energy in the system will be conserved.  There aught to be a law.

[Scout26]

Almost as if the total energy in the system will be conserved.  There aught to be a law.

Thank you.  Just woke up.  Can't brain yet.

[freakazoid]

So "Free Energy" ??   If you use the trailer to generate electricity, then you have to factor in resistance, friction, and battery charge loss.  In other words, you use more energy putting into the battery then you can get out latter.

https://batteryuniversity.com/

The energy you are putting into it is already happening, might as well capture some of it.

[Scout26]

The energy you are putting into it is already happening, might as well capture some of it.

But you are not.  There is more energy used to turn the wheels of the trailer (plus loss through heat and battery recharge) that you use "more" to generate a little. 

If this were the case, the you could hook up many, many alternators to an engine, use it to charge a battery then turn off the engine and just continuously use the alternator to battery to wheel to alternator model to have "Free Energy", but the loss through heat and friction (and driving enough current through the batteries to charge them), means that all the energy going in is coming out in non-productive ways.  Thus you don't get any more then what is put in.

https://en.wikipedia.org/wiki/Conservation_of_energy

[Mannlicher]

maybe some day,  but certainly not interested today.  There is no practical reason for electric cars.   They are NOT "environmentally friendly", their power has to come from a power plant somewhere.

[dogmush]

The energy you are putting into it is already happening, might as well capture some of it.

What you are neglecting is that a wheel with a generator on it is harder to turn, so it will take more energy to pull the trailer that is generating then the one that is not.  Indeed the difference in energy needed to pull the two trailers will be more than the energy the generating trailer produces, no matter what, due to conversion loss and transfer efficiencies.

[freakazoid]

What you are neglecting is that a wheel with a generator on it is harder to turn, so it will take more energy to pull the trailer that is generating then the one that is not.  Indeed the difference in energy needed to pull the two trailers will be more than the energy the generating trailer produces, no matter what, due to conversion loss and transfer efficiencies.

Yeah but, and? That's like saying you don't have a cigarette lighter/energy jack, or USB port, to power some electronic device because it uses extra energy. Or saying that you don't use an emergency gas generator because it uses gas. The purpose is as either an emergency power or as recreational power later or whatever you want to use it for without needing to run the car or some noisy generator.

[Doggy Daddy]

Yeah but, and?

Ever tried to turn a generator by hand?  Flashlight or radio?  Generators take energy to turn.  When you crank your little emergency generator by hand, you are NOT making power.  You are converting the power of your arm into electric.  A generator attached to a wheel will convert the power of the wheel into electric instead of into moving the vehicle down the road.  And the vehicle will stop.

[Scout26]

Yeah but, and? That's like saying you don't have a cigarette lighter/energy jack, or USB port, to power some electronic device because it uses extra energy.

Those do.  In a car with a gas engine it might not be as noticeable, but the more drag you put on the alternator by powering more
"things", the more your gas mileage is reduced. 

Or saying that you don't use an emergency gas generator because it uses gas. The purpose is as either an emergency power or as recreational power later or whatever you want to use it for without needing to run the car or some noisy generator.

But it would be more efficient to use a generator for recreational power later.   Basically you are taking 100% of the energy from the EV's battery, losing some to friction in the motor, friction of the truck tires on the road, friction of the trailer tires on the road, friction of the generator motor in  the trailer, then the transfer loss of electrons in the batteries in the trailer.  So you end up with what 10% maybe 20% of what electricity you initially stored into the EV's battery??

A much better solution would be to use the EV to directly power your campsite.  But, either way you are dramatically reducing the range of the vehicle. 

[Firethorn]

I know that's one of the ways EVs do it now, but I would think i you are towing a trailer that the trailer itself might have the capacity to provide a massive amount of energy for recharging. Actually thinking about it now, even non-EVs might benefit from trailers with this hookup. Could provide a backup power if you ever had to jumpstart yours or someone else's vehicle, or power if the trailer is used for camping without having to run a generator or anything. Hmmm...

Well, I did posit two ways for the trailer to help.  The first would be to put a generator in it(note, most portable generators aren't very well tuned for efficiency), the second would be to have it carry more batteries in order to 'pay for itself'. 

Putting generators on the wheels, given how easy it is to have generators also act as motors and vice versa, means that you're really turning the trailer into an unguided EV. 

That leads to a third way, actually. Put a small engine with a transmission hooked into it.  They're called "pusher trailers".  The idea is that the engine stays off until you're traveling at highway speeds, allowing a very truncated transmission.  The engine pushes the trailer and towing EV at somewhere around the force necessary to maintain highway speeds - maybe a bit more, maybe a bit less.