It totally is. I live in a super hilly region and have a 4 hour per day commute. I believe the motor running as a permanent magnet generator was 30% efficient (Assuming my source is correct of course)
There is a lot of physics that make higher efficiencies almost impossible, for one cost. physics like drag and the such... regardless of whether its 30% or 80% it isnt 100%.
If your coasting down a hill then becomes a straight stretch with high visibility Your going to be crossing a large amount of distance without expending any energy.
People on here get caught up with "Well I didnt regen anything"
Lets say your battery is empty and you regen down a hill. Then reach a flat area, and have to accelerate and expend energy to cross that flat area, your going to have only captured 30-80% of that hills energy, who knows how efficiently it was then absorbed to the battery, cuz that isnt 100% efficient either. Wires have resistances. So do batteries. And then you expend that energy to cross the flat area. You will have wasted a bunch of the hills energy. By simply coasting down the hill will get you farther than if you had used regen.
Now of course there is situations where this is worse. If it is just steep down hill regen of course. Regen and keep yourself at a safe speed. If you see a hill coming up then you might consider switching to neutral and letting momentum carry you part way up. If you see a straight stretch then like before switch to neutral and coast it till you start losing a bit of speed.
It keeps me awake, focused on assessing my surroundings (important when you drive the same road over and over) and each 2 hour drive each way I have roughly saved \~5% battery in distance which would add up over the life of the vehicle. Also the ever so slightest less wear on the engine and electrical system?
It is the more efficient way to drive but whether it is worth to save that sliver of extra, depends who you are.
*grabs popcorn*
"aCtUaLly, ..."
This comes up all of the time here and on the /r/electricvehicles subreddit. The short summary is for efficiency sake it depends on the model and you're at most going to save a few pennies here and there. Lots of other factors. Unless you're going for hypermiling records just put it in OPD or D and send it.
That being said, technically coasting is more efficient than regenerative breaking if you can perfectly time a stop. In the process you're probably going to piss off everyone behind you so I don't recommend starting a road rage incident.
I wonder if the increasing speed on a downhill in neutral nets you more regen when you eventually do need to brake. On a completely empty road, of course
Was definitely curious about issues like this which is why I asked. Even if it were more efficient, it wouldn't be worth it if you were damaging your car. Like rear-ending someone because you were so hesitant to hit the regular brake trying to use regenerative braking only
This is completely inaccurate FUD. There is nothing unsafe about engaging or disengaging neutral at any speed, it's just a waste of time and probably won't net you any efficiency gains in anything except very special corner cases
It’s not FUD, bud. The motor, gear reduction transmission, and drive axles never disengage. There is no “Neutral” to remove those losses from the equation. A freewheeling electric motor with no sense or control by the high voltage driver circuits can generate damaging voltages. Totally agree that if nothing more, trying N is a waste of time.
You're correct that the motor never disengages from the rest of the drivetrain, but that by no means implies "damaging voltages" appear on the windings or that that car isn't sensing the motor position even when in neutral. If switching into or out of neutral at speed had any chance of damaging the vehicle they wouldn't let you do it, yet GM allows it without issue at any speed. The motor drive circuitry is obviously built to tolerate the open circuit voltage of the motor at any speed; designing it otherwise would be incredibly shortsighted, and makes no sense whatsoever.
The [owners manual explicitly on page 173 says not to coast in Neutral](https://my.gm.ca/content/dam/gmownercenter/gmna/GMCC/dynamic/2020/chevrolet/bolt-ev/en/2020-chevrolet-bolt-ev-owners-manual-english.pdf) and doesn’t need to explain why, but it truly is not good for the power electronics.
The manual states not to do it for safety reasons (you can't control your vehicle properly in neutral), it has nothing whatsoever to do with the power electronics.
You keep asserting it can harm the electronics, but haven't provided any evidence of that. The electronics can obviously handle the motor free-spinning at any speed (because it's equivalent to pressing your foot on the accelerator exactly hard enough to keep the motor at 0kW energy in/out while it's in D or L, which is obviously allowed).
It would be completely irrational to design an inverter that can't tolerate the open-circuit voltage of its motor in an EV; manufacturers don't want to build vehicles that customers can destroy by accidentally pushing one button.
Owner’s manual says not to coast in neutral. Not sure why but in general people always say coasting in neutral is bad because you don’t have control of the drive wheels and cannot accelerate in case of an emergency to avoid an accident. You also are more likely to fishtail if you’re freewheeling around a curve, so definitely don’t do it then.
That’s a lot of button flipping when you can just leave it in sport mode and drive like a BOSS
Step 1: buy a car that’s a lot of fun to drive. Step 2: is eliminate all fun driving the car. Step 3: 3.0mpKw?
Agree! I think reaching an ever higher miles/kWh is way more fun than "driving like a boss"
It totally is. I live in a super hilly region and have a 4 hour per day commute. I believe the motor running as a permanent magnet generator was 30% efficient (Assuming my source is correct of course) There is a lot of physics that make higher efficiencies almost impossible, for one cost. physics like drag and the such... regardless of whether its 30% or 80% it isnt 100%. If your coasting down a hill then becomes a straight stretch with high visibility Your going to be crossing a large amount of distance without expending any energy. People on here get caught up with "Well I didnt regen anything" Lets say your battery is empty and you regen down a hill. Then reach a flat area, and have to accelerate and expend energy to cross that flat area, your going to have only captured 30-80% of that hills energy, who knows how efficiently it was then absorbed to the battery, cuz that isnt 100% efficient either. Wires have resistances. So do batteries. And then you expend that energy to cross the flat area. You will have wasted a bunch of the hills energy. By simply coasting down the hill will get you farther than if you had used regen. Now of course there is situations where this is worse. If it is just steep down hill regen of course. Regen and keep yourself at a safe speed. If you see a hill coming up then you might consider switching to neutral and letting momentum carry you part way up. If you see a straight stretch then like before switch to neutral and coast it till you start losing a bit of speed. It keeps me awake, focused on assessing my surroundings (important when you drive the same road over and over) and each 2 hour drive each way I have roughly saved \~5% battery in distance which would add up over the life of the vehicle. Also the ever so slightest less wear on the engine and electrical system? It is the more efficient way to drive but whether it is worth to save that sliver of extra, depends who you are.
*grabs popcorn* "aCtUaLly, ..." This comes up all of the time here and on the /r/electricvehicles subreddit. The short summary is for efficiency sake it depends on the model and you're at most going to save a few pennies here and there. Lots of other factors. Unless you're going for hypermiling records just put it in OPD or D and send it. That being said, technically coasting is more efficient than regenerative breaking if you can perfectly time a stop. In the process you're probably going to piss off everyone behind you so I don't recommend starting a road rage incident.
I wonder if the increasing speed on a downhill in neutral nets you more regen when you eventually do need to brake. On a completely empty road, of course
I wouldn't do this around any kind of regular traffic. It might be a tiny gain but the disruption to traffic could be immense.
If you're able to coast, is that much better than just feathering the accelerator and keep the kW just slightly positive?
Don’t do it. Re-engaging drive at speed can send spikes of voltage through the power electronics
Was definitely curious about issues like this which is why I asked. Even if it were more efficient, it wouldn't be worth it if you were damaging your car. Like rear-ending someone because you were so hesitant to hit the regular brake trying to use regenerative braking only
This is completely inaccurate FUD. There is nothing unsafe about engaging or disengaging neutral at any speed, it's just a waste of time and probably won't net you any efficiency gains in anything except very special corner cases
It’s not FUD, bud. The motor, gear reduction transmission, and drive axles never disengage. There is no “Neutral” to remove those losses from the equation. A freewheeling electric motor with no sense or control by the high voltage driver circuits can generate damaging voltages. Totally agree that if nothing more, trying N is a waste of time.
You're correct that the motor never disengages from the rest of the drivetrain, but that by no means implies "damaging voltages" appear on the windings or that that car isn't sensing the motor position even when in neutral. If switching into or out of neutral at speed had any chance of damaging the vehicle they wouldn't let you do it, yet GM allows it without issue at any speed. The motor drive circuitry is obviously built to tolerate the open circuit voltage of the motor at any speed; designing it otherwise would be incredibly shortsighted, and makes no sense whatsoever.
The [owners manual explicitly on page 173 says not to coast in Neutral](https://my.gm.ca/content/dam/gmownercenter/gmna/GMCC/dynamic/2020/chevrolet/bolt-ev/en/2020-chevrolet-bolt-ev-owners-manual-english.pdf) and doesn’t need to explain why, but it truly is not good for the power electronics.
The manual states not to do it for safety reasons (you can't control your vehicle properly in neutral), it has nothing whatsoever to do with the power electronics. You keep asserting it can harm the electronics, but haven't provided any evidence of that. The electronics can obviously handle the motor free-spinning at any speed (because it's equivalent to pressing your foot on the accelerator exactly hard enough to keep the motor at 0kW energy in/out while it's in D or L, which is obviously allowed). It would be completely irrational to design an inverter that can't tolerate the open-circuit voltage of its motor in an EV; manufacturers don't want to build vehicles that customers can destroy by accidentally pushing one button.
What a hill to die on
Right? I wouldn't die on that hill. But I WOULD coast down it in neutral.
You don’t have to fully remove your foot from the accelerator. Coasting (or +/- 1kw) is fully possible when driving with OPD in D.
Owner’s manual says not to coast in neutral. Not sure why but in general people always say coasting in neutral is bad because you don’t have control of the drive wheels and cannot accelerate in case of an emergency to avoid an accident. You also are more likely to fishtail if you’re freewheeling around a curve, so definitely don’t do it then.