Charging Electric Cars

reboot

Seweryn wrote: »

It is not a dynamo. It is the electric motor that drives the car. The same motor that sends the power to wheels during braking works as a generator (like any electric motor) and produces energy.

Charging while going downhill doesn't involve braking?

reboot

Big Nasty wrote: »

Agreed! Anyhow, I love petrol (sniff) and I consider diesel to be the fuel of the devil so I'll be staying petrol until I am completely forced to do otherwise.

Unfortunately I reckon I probably will see this within my lifetime. :mad:

I agree about you.

Bruthal

Eric Cartman wrote: »

the extra friction created by the dynamo would make the motor consume as much if not more power than the dynamo was putting out, it works while braking because the motor is not doing any work,

Its not really friction from the dynamo as such, its an electromagnetic drag or braking effect.

As a dynamo generates electric current, this generates a magnetic field. This field opposes the rotation of the dynamo. In simple terms, the higher the current generated, the harder the dynamo is to turn. To charge a battery takes a little more kilowatt hours input than what the battery can then output, so charging with a dynamo will consume more energy than it generates, during normal driving.

reboot

Bruthal wrote: »

Its not really friction from the dynamo as such, its an electromagnetic drag or braking effect.

As a dynamo generates electric current, this generates a magnetic field. This field opposes the rotation of the dynamo. In simple terms, the higher the current generated, the harder the dynamo is to turn. To charge a battery takes a little more kilowatt hours input than what the battery can then output, so charging with a dynamo will consume more energy than it generates, during normal driving.

I agree regarding the Back EMF, but I don't see any charging during "Normal driving", but when taking my foot off going down a slight hill. Surely if I end up with say 4 more miles more than when I set off, which regularly occurs at my location, the dynamo must have charged the battery over the distance?

There is no charging during normal driving, only when you back off the throttle and the regen kicks in.

Regen isn't as efficient as coasting when you lift off the throttle because of inefficiencies, so in other words it's more efficient to have 0 regen unless you actually "want/need" to slow down, the idea is you roll using energy used for as long as you can.

reboot

Deleted User wrote: »

There is no charging during normal driving, only when you back off the throttle and the regen kicks in.

Regen isn't as efficient as coasting when you lift off the throttle because of inefficiencies, so in other words it's more efficient to have 0 regen unless you actually "want/need" to slow down, the idea is you roll using energy used for as long as you can.

I see regen with my foot on the throttle on a daily basis?

reboot

reboot wrote: »

I see regen with my foot on the throttle on a daily basis?

You have to lift off the throttle for regen to engage.

Thank god at least the leaf has the option of much stronger regen in Eco and not strong in normal, the zoe regen is far too strong when you lift off the throttle, at least give people an option for low med or high regen or no regen at all or only regen when you press the brake.

Again my point is that coasting is more efficient than regen because during regen there are losses in the conversion of kinetic energy back to electrical.

Coasting uses no extra energy. Regen is ideal where you want / need to brake not when a computer decides you want to brake.

reboot

Deleted User wrote: »

You have to lift off the throttle for regen to engage.

Thank god at least the leaf has the option of much stronger regen in Eco and not strong in normal, the zoe regen is far too strong when you lift off the throttle, at least give people an option for low med or high regen or no regen at all or only regen when you press the brake.

Again my point is that coasting is more efficient than regen because during regen there are losses in the conversion of kinetic energy back to electrical.

Coasting uses no extra energy. Regen is ideal where you want / need to brake not when a computer decides you want to brake.

When you say "Lift off the throttle' do you mean simply reduce, I find regen still occurs when I simply reduce, not completely lift off.

reboot

reboot wrote: »

When you say "Lift off the throttle' do you mean simply reduce, I find regen still occurs when I simply reduce, not completely lift off.

Maybe it does on the Zoe, that's even worse, this means that you're always either using power or using regen which also has losses.

The regen I found on Zoe horribly strong and annoying, I really do not like that forced hard slow down when you lift off the throttle. I want the car to brake when I want it to not when the computer or renault tell me the car should.

I think they should have had different regen strengths or variable regen like the E-Golf via flappy paddles on the steering.

With the leaf, regen is much stronger in eco but you can get netural or very close to it via a certain throttle position much the same as the prius but in the prius it only works up to 71 Kph.

In the leaf one pedal driving is a lot more comfortable when you can keep the car going via momentum in neutral then lift off the throttle altogether and you got good braking.

I did not have enough time in the Zoe to find out if there is a certain throttle position that gives you neutral.

Dexter1979

There is a neutral throttle position and it's a very light rolling car when you coast. You can change the dashboard display to an arch with different sections. The small section between Blue (regen) and Green (eco power use) is neutral. Combine this with changing the right information side to Direct Consumption and you will see it stay at 0kW while coasting. I have seen regen as high as 20kW when lifting off the accelerator and just let the car decide.

That's something at least that you can get neutral with a certain throttle position on the zoe.

reboot

Deleted User wrote: »

Maybe it does on the Zoe, that's even worse, this means that you're always either using power or using regen which also has losses.

The regen I found on Zoe horribly strong and annoying, I really do not like that forced hard slow down when you lift off the throttle. I want the car to brake when I want it to not when the computer or renault tell me the car should.

I think they should have had different regen strengths or variable regen like the E-Golf via flappy paddles on the steering.

With the leaf, regen is much stronger in eco but you can get netural or very close to it via a certain throttle position much the same as the prius but in the prius it only works up to 71 Kph.

In the leaf one pedal driving is a lot more comfortable when you can keep the car going via momentum in neutral then lift off the throttle altogether and you got good braking.

I did not have enough time in the Zoe to find out if there is a certain throttle position that gives you neutral.

Are you seriously suggesting
driving an automatic at speed in Neutral?

reboot

reboot wrote: »

Are you seriously suggesting
driving an automatic at speed in Neutral?

It isn't an automatic, there's no gearbox in an ev.

There is a single fixed reducer gear to reduce the high rpm of the motor.

But I wasn't referring putting the car into neutral but more finding the neutral position from the accelerator while the car is still in drive/eco.

Dexter1979

reboot wrote: »

Are you seriously suggesting
driving an automatic at speed in Neutral?

If you position your foot to get 0 kW direct consumption you are effectively driving in a controlled version of Neutral. And I do this regularly. Let gravity accelerate the car instead of my battery

reboot

Deleted User wrote: »

It isn't an automatic, there's no gearbox in an ev.

There is a single fixed reducer gear to reduce the high rpm of the motor.

But I wasn't referring putting the car into neutral but more finding the neutral position from the accelerator while the car is still in drive/eco.

You are both right of course , and I agree,just wasn't very clear.My fault for not reading it closely enough, you did say throttle.