3 ms·

A tesla can slow down much much faster than 1 mile an hour per second with regenerative brakes. As you said, if the battery is really full (like 99%, but not 80

A tesla can slow down much much faster than 1 mile an hour per second with regenerative brakes. As you said, if the battery is really full (like 99%, but not 80%) even on a tesla it uses regular braking when full, but once you drive a tesla 10 or 15 miles it has room to do regen braking. also you don't typically charge it to 100% every day, i only charge to the recommended ~90% - so i'm always ready for regen. You drive it in a certain mode where you don't need to use the brakes much, just take your foot off the gas pedal and it slows down rapidly. That's not good enough for say emergency stopping on the freeway but I don't need to emergency stop much. But on a tesla at least the regen braking takes speed off much faster. there are two things at play, just taking off the power will start to slow you down, but you can see the breaking impact when you car is using negative power.

stephengillie 8y ago
Kinetic energy increases at the square of velocity - so a 4400 lb car, accelerating from 64 MPH to 65 uses 7.25 KW, while going from stopped (0 MPH) to about 7 MPH uses slightly more, 7.75 KW. It takes additional energy to add energy to a system that already has some energy. For example, recharging a partially-full battery from 70% to 90% will take more energy (or time) than charging from 5% to 25%. At 65 MPH, it takes my Camry Hybrid over a second to absorb 1 MPH and reduce to 64 MPH, with only regenerative braking. At 35, it can absorb several MPH per second. Like a Tesla, the regenerative braking is always slowing the car down, but unlike a Tesla, it only regenerates at 5%-10% until the brake pedal is pressed, which is reflected by the "tachometer" dipping down into the blue CHG section.
- davidgould 8y ago
  > a 4400 lb car, accelerating from 64 MPH to 65 uses 7.25 KW My Chevy Spark EV can regenerate at up to 60 KW. Forward drive tops at 100 KW. The regen limit is due to the battery charge rate, the bigger the battery, the more charge it can accept. > It takes additional energy to add energy to a system that already has some energy. For example, recharging a partially-full battery from 70% to 90% will take more energy (or time) than charging from 5% to 25% Why do you say "additional energy"? Do you mean "additional time", because that makes some sense as DC quick charging usually tapers off in rate as the battery becomes full. Please explain this if you actually mean additional energy as it is confusing.

stephengillie 8y ago

Kinetic energy increases at the square of velocity - so a 4400 lb car, accelerating from 64 MPH to 65 uses 7.25 KW, while going from stopped (0 MPH) to about 7 MPH uses slightly more, 7.75 KW. It takes additional energy to add energy to a system that already has some energy. For example, recharging a partially-full battery from 70% to 90% will take more energy (or time) than charging from 5% to 25%. At 65 MPH, it takes my Camry Hybrid over a second to absorb 1 MPH and reduce to 64 MPH, with only regenerative braking. At 35, it can absorb several MPH per second. Like a Tesla, the regenerative braking is always slowing the car down, but unlike a Tesla, it only regenerates at 5%-10% until the brake pedal is pressed, which is reflected by the "tachometer" dipping down into the blue CHG section.

davidgould 8y ago
> a 4400 lb car, accelerating from 64 MPH to 65 uses 7.25 KW My Chevy Spark EV can regenerate at up to 60 KW. Forward drive tops at 100 KW. The regen limit is due to the battery charge rate, the bigger the battery, the more charge it can accept. > It takes additional energy to add energy to a system that already has some energy. For example, recharging a partially-full battery from 70% to 90% will take more energy (or time) than charging from 5% to 25% Why do you say "additional energy"? Do you mean "additional time", because that makes some sense as DC quick charging usually tapers off in rate as the battery becomes full. Please explain this if you actually mean additional energy as it is confusing.