OOI, do all EVs use regenerative braking to top up the batteries?
Yes as far as i know. Its one way they eke out the range. I generally only touch the brake pedal for the final few metres to come to a stop.
OOI, do all EVs use regenerative braking to top up the batteries?
The old Milk Floats I don't think had regenerative braking, and neither did the old fork lifts, but by 1984 CAT fork lifts had regenerative braking but not through the brake peddle, correct procedure was to put them in reverse, in real terms it did not work as instead of just stopping they would start going back wards, so not really used even if that is what the manual said to do.OOI, do all EVs use regenerative braking to top up the batteries?
If I've done my sums right, assuming a 1,000kg car and assuming 100% efficiency in converting the car's kinetic energy into electrical energy, braking from 30mph to zero would produce about 89,780 Joules, aka about 25 Wh (i.e. 0.025 kWh). I've no idea how far the car could go with that amount of electrical energy!Braking from 30mph using regenerative braking. How far would you get using the energy put back into the battery? 100yds?
Assuming a spherical car in a vacuum, anywhere you like!If I've done my sums right, assuming a 1,000kg car and assuming 100% efficiency in converting the car's kinetic energy into electrical energy, braking from 30mph to zero would produce about 89,780 Joules, aka about 25 Wh (i.e. 0.025 kWh). I've no idea how far the car could go with that amount of electrical energy!
Kind Regards, John
If it's in a vacuum, I doubt that the shape would matter!Assuming a spherical car in a vacuum, anywhere you like!
The mass of the car is irrelevant. If your regenerative braking is 100% efficient then surely you would be accelerating at the same rate when decreasing velocity as increasing it?If I've done my sums right, assuming a 1,000kg car and assuming 100% efficiency in converting the car's kinetic energy into electrical energy, braking from 30mph to zero would produce about 89,780 Joules, aka about 25 Wh (i.e. 0.025 kWh). I've no idea how far the car could go with that amount of electrical energy!
Where are you suggesting that all the kinetic energy of the moving car (which is proportional to its mass) goes when it is brought to a halt? As I said, I was assuming that all that kinetic energy would be turned into electrical energy, although that obviously is not the case in the real world. In the absence of regenerative braking, that energy will be converted to heat.The mass of the car is irrelevant.
Maybe it's because of the time of day (or 'old age') but, I'm sorry, I don't understand that.If your regenerative braking is 100% efficient then surely you would be accelerating at the same rate when decreasing velocity as increasing it?
AIUI, yes they do - though it's a user configurable parameter (according to some articles I've read). Again, this is from reviews I've read, not first hand experience, but when you "lift off the gas" they go into regenerative mode - to give a feel like engine braking. The first stages of pressing the brake pedal also trigger more regeneration. I've certainly read comments that if set to use more "engine braking", the feel is quite distinctive.OOI, do all EVs use regenerative braking to top up the batteries?
Well given the impressive figures* they get for urban driving, one has to assume that it has some effect on consumption. AIUI electric-mechanical conversion and the reverse isn't too bad efficiency wise - so you might save (stick finger in air) say 50%. That's 50% of your kinetic energy not going to heat the atmosphere.Braking from 30mph using regenerative braking. How far would you get using the energy put back into the battery? 100yds?
As you will have seen, my recent calculations (if I got them right) suggest that, for a 1000 kg car, and assuming 100% 'regeneration efficiency', braking from 30 mph to rest would regenerate about 25 Wh of electricity. Taking your guesstimate of an actual efficiency of 50%, lets say that a more realistic figure is 12.5 Wh for one episode of such braking.Well given the impressive figures* they get for urban driving, one has to assume that it has some effect on consumption. AIUI electric-mechanical conversion and the reverse isn't too bad efficiency wise - so you might save (stick finger in air) say 50%. That's 50% of your kinetic energy not going to heat the atmosphere.
Back into the battery.Where are you suggesting that all the kinetic energy of the moving car (which is proportional to its mass) goes when it is brought to a halt?
Yes - it is not a realistic model, but theoretically you accelerate a mass to x m/s, and then you accelerate it to 0 m/s. The mass is irrelevant.As I said, I was assuming that all that kinetic energy would be turned into electrical energy, although that obviously is not the case in the real world. In the absence of regenerative braking, that energy will be converted to heat.
Or maybe because it was nonsense.Maybe it's because of the time of day (or 'old age') but, I'm sorry, I don't understand that.
But even if you were, that would not be enough - every "ordinary" car can accelerate far more when slowing down than when speeding up.
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