Overnight Charge

[miimura]

My point is that the motor can still slow the vehicle without using the friction pads and without sending juice to the battery.

In trains, they use large banks of capacitors. In our cars, in hybrids they spin the engine to shed heat, and in our cars they could wind the motor at a safe rate to shed that excess heat as well (and could be why he's feeling degenerative braking power in B at full charge).

No. Modern electric cars cannot slow the car in a meaningful way without dumping the energy into the battery. There are no resistor banks or capacitor banks to absorb that energy. When the battery cannot safely take any more energy, the car has no choice but to blend in the friction brakes at a much earlier point than they would when the battery is at a lower state of charge. VW actually did such a good job with the brake blending that if you drive in D, you would not notice the lack of regen braking without looking at the gauge. It doesn't feel any different.

 

[JoulesThief]

My point is that the motor can still slow the vehicle without using the friction pads and without sending juice to the battery.

In trains, they use large banks of capacitors. In our cars, in hybrids they spin the engine to shed heat, and in our cars they could wind the motor at a safe rate to shed that excess heat as well (and could be why he's feeling degenerative braking power in B at full charge).

No. Modern electric cars cannot slow the car in a meaningful way without dumping the energy into the battery. There are no resistor banks or capacitor banks to absorb that energy. When the battery cannot safely take any more energy, the car has no choice but to blend in the friction brakes at a much earlier point than they would when the battery is at a lower state of charge. VW actually did such a good job with the brake blending that if you drive in D, you would not notice the lack of regen braking without looking at the gauge. It doesn't feel any different.

You can confirm electric regenerative braking quite simply, every time you need to slow down, enter the car into "B" mode with the shift selector. It will give you an idea how close to topped off your battery is, in a hurry, if you find out it's not slowing you down and you have to manually step on the brake pedal to get some braking action.

 

[DasCC]

My point is that the motor can still slow the vehicle without using the friction pads and without sending juice to the battery.

In trains, they use large banks of capacitors. In our cars, in hybrids they spin the engine to shed heat, and in our cars they could wind the motor at a safe rate to shed that excess heat as well (and could be why he's feeling degenerative braking power in B at full charge).

No. Modern electric cars cannot slow the car in a meaningful way without dumping the energy into the battery. There are no resistor banks or capacitor banks to absorb that energy. When the battery cannot safely take any more energy, the car has no choice but to blend in the friction brakes at a much earlier point than they would when the battery is at a lower state of charge. VW actually did such a good job with the brake blending that if you drive in D, you would not notice the lack of regen braking without looking at the gauge. It doesn't feel any different.

I was wondering about this... I cannot feel the difference between the friction brakes and regen. I had it my head it would be very apparent.

 

[JoulesThief]

My point is that the motor can still slow the vehicle without using the friction pads and without sending juice to the battery.

In trains, they use large banks of capacitors. In our cars, in hybrids they spin the engine to shed heat, and in our cars they could wind the motor at a safe rate to shed that excess heat as well (and could be why he's feeling degenerative braking power in B at full charge).

No. Modern electric cars cannot slow the car in a meaningful way without dumping the energy into the battery. There are no resistor banks or capacitor banks to absorb that energy. When the battery cannot safely take any more energy, the car has no choice but to blend in the friction brakes at a much earlier point than they would when the battery is at a lower state of charge. VW actually did such a good job with the brake blending that if you drive in D, you would not notice the lack of regen braking without looking at the gauge. It doesn't feel any different.

I was wondering about this... I cannot feel the difference between the friction brakes and regen. I had it my head it would be very apparent.

It would appear as though the engineers at VW have made this appear and function as seamless as possible.


https://forums.tdiclub.com/search.php?searchid=17135030

 

[bizzle]

I'm a professor of law. People in some threads specifically asked for an opinion regarding the law and I provided one.

I don't appreciate your personal attacks. We were simply having a conversation here and you've turned the conversation rather personal for no apparent reason. If anyone's demonstrated an absolute need to be correct and argumentative it appears to be you from my perspective...and you don't just do it with me, either.

 

[ulrichw]

Agree - JoulesThief you're out of line here.

 

[phr00t]

Agree - JoulesThief you're out of line here.

Also showing my agreement. Let's keep things civil and on topic. Trying to diagnose mental conditions over the internet is textbook trolling & I'd be nice to not see it here.

 

[mfennell]

Indeed. bizzle is in no way out of line, he just doesn't understand the details.

 

[phr00t]

Not understanding details is fine. That is one of the reasons we post & read here, to help each other understand.

 

[JoulesThief]

Not understanding details is fine. That is one of the reasons we post & read here, to help each other understand.

Still waiting for bizzle's test drive, once his wife came home with the e-golf, and the braking results.

I am not interested in railroad train braking theory on a car, with capacitors. Apples and oranges, does not apply here, unless he can prove that on e-Golfs there is capacitors used for braking in the design, instead of using the rotors and brake pads, when battery state is near top charge.

What I do know is that electrical load, in the form of resistance, being it to chemically recharge the Li battery pack, or to generate heat, burning it off through electrical resistance, and generating heat, in regenerative braking, works on an e-golf. If the battery pack is near full charge, the battery can not take on additional amps and volts, usually the voltage peaks at near 4.20V per cell, for most LiIon chemistry in a battery cell, and then the amperage gets reduced, as a battery nears top charge, the chemical reaction taking place recharging becomes slower and slower. This translates into the motor that is being used in inverse, as a generator, to have less rotational resistance in the form of generator load, hence, less braking action performed by the motor in generating mode.

This is not noticeable if you step on the brake pedal in an e-golf, near top charge. It is very noticeable if you move the shifter into "B" mode, near a top charge, to slow down or stop, versus when discharged slightly. Try it some time, like bizzle said he would.

 

[miimura]

This is kind of a semantic difference, but it's not the batteries that are refusing to take the charge when they are full, but rather the car's computer is reducing the negative torque command (regen) to avoid putting a higher voltage into the battery that would damage it.