[redpoint5]

So true.
Accelerating an EV:
0 - 60 mph in 10 seconds, hit cruise.
0 - 60 mph in 60 seconds, hit cruise.

Is there any measurable difference in kWh consumption in a 1 mile trip? In a 100 mile trip?
I think it's not wasteful to have your back pushed into the seat while accelerating quickly.
It is in a gasser.

The amount of energy required to accelerate from 0-60 is the same regardless of how quickly you do it. The difference then comes down only to the difference in the efficiency of the drivetrain at various power levels. EV motors are very efficient across most of the RPM and power levels. There is a difference in efficiency, but it's too small to make a meaningful difference.

ICE engines operate most efficiently around 75% of peak torque and around 2,500 RPM, depending on engine. That translates to roughly half of maximum power output. ICE engines are extremely inefficient when operating at low torque (light throttle positions), and are still fairly efficient at wide open throttle. It's why ICE get better MPG in rolling hills to moderate grades than flat roads.

 

[LighteningBug]

Same^ eh, similar. Heating of the motor, wheel heat loss, area under the speed curve over the trip (wind resistance) this changes with faster and slower acceleration.

So true.
Accelerating an EV:
0 - 60 mph in 10 seconds, hit cruise.
0 - 60 mph in 60 seconds, hit cruise.

Is there any measurable difference in kWh consumption in a 1 mile trip? In a 100 mile trip?
I think it's not wasteful to have your back pushed into the seat while accelerating quickly.
It is in a gasser.

it seems like faster acceleration might hurt in heat losses in the wheels and tire wear.

I have heard from hypermilers that there may be something to fast acceleration efficiency wise though, but it doesn’t make much sense to me.

there is also more higher speed under the curve on a fast acceleration.

 

[Packard V8]

It's why ICE get better MPG in rolling hills to moderate grades than flat roads.

You've stated that here several times, but I can find no citations to actual tests proving this. Can you share some?

I have heard from hypermilers that there may be something to fast acceleration efficiency wise though, but it doesn’t make much sense to me.

Because you don't understand extreme hypermiling has no real world application. In hypermiling contests, the ICEs are operated in "burst-and-coast" mode. An ICE is most efficient, has less pumping loss, at wide-open-throttle. The engine is at WOT up to the most efficient speed, usually 40 MPH, then fuel is cut and transmission freewheels down to approx 20 MPH, where the engine fires again and pulls back up to 40 MPH.

How would you like to be following that guy on the highway? It would be reminiscent of the bad old days before freeways and before big trucks had turbochargers. You'd follow trucks through the Great Smoky Mountains, crawling slowly up to the top, then down the other side in "Georgia Overdrive" they'd build as much speed as engine and gravity could, making passing on curvy two lanes impossible.

jack vines

 

[efbolt]

So true.
Accelerating an EV:
0 - 60 mph in 10 seconds, hit cruise.
0 - 60 mph in 60 seconds, hit cruise.

Is there any measurable difference in kWh consumption in a 1 mile trip? In a 100 mile trip?
I think it's not wasteful to have your back pushed into the seat while accelerating quickly.
It is in a gasser.

It depends on how much you start and stop, but technically slower acceleration means more time spent at lower speeds. So, in that sense, it would increase efficiency.

 

[efbolt]

You've stated that here several times, but I can find no citations to actual tests proving this. Can you share some?

Because you don't understand extreme hypermiling has no real world application. In hypermiling contests, the ICEs are operated in "burst-and-coast" mode. An ICE is most efficient, has less pumping loss, at wide-open-throttle. The engine is at WOT up to the most efficient speed, usually 40 MPH, then fuel is cut and transmission freewheels down to approx 20 MPH, where the engine fires again and pulls back up to 40 MPH.

How would you like to be following that guy on the highway? It would be reminiscent of the bad old days before freeways and before big trucks had turbochargers. You'd follow trucks through the Great Smoky Mountains, crawling slowly up to the top, then down the other side in "Georgia Overdrive" they'd build as much speed as engine and gravity could, making passing on curvy two lanes impossible.

jack vines

That's why I utilize L mode. I'm not coasting to a red light from half a mile away.

I do find it funny when people accelerate when a red light is 100 ft away though.

 

[Packard V8]

That's why I utilize L mode. I'm not coasting to a red light from half a mile away. I do find it funny when people accelerate when a red light is 100 ft away though.

For true; L mode encourages precision driving; I know the timing of my local lights and the one ahead is red and I'm on pace to reach it as it changes and the cars waiting get moving. The guy approaching from behind can see the red light and stopped traffic, but still passes me at full speed and then has to brake hard. As it goes green, I pass him, still at the same speed as traffic moves off.

jack vines

 

[evtinker]

For true; L mode encourages precision driving; I know the timing of my local lights and the one ahead is red and I'm on pace to reach it as it changes and the cars waiting get moving. The guy approaching from behind can see the red light and stopped traffic, but still passes me at full speed and then has to brake hard. As it goes green, I pass him, still at the same speed as traffic moves off.

jack vines

I did this many years ago one time while driving my ’75 Citicar (3.5 hp top speed 38 mph). Over a distance of about 3 miles, I hit every light green while the guy next to me launched hard and got caught be every light. I passed him again and again, each time he punched it harder on the green to try to beat the next light. I finally got concerned he was getting too angry, so I pulled of into a parking lot to let him continue on alone.

 

[NortonCommando]

That's why I utilize L mode. ...

But L mode does nothing for efficiency.
You are always in control of the accel and decel rates regardless of L or D modes.
The Brake Pedal is a variable Regen Pedal, until max regen is reached, then friction brakes blend in.

 

[redpoint5]

You've stated that here several times, but I can find no citations to actual tests proving this. Can you share some?

Because you don't understand extreme hypermiling has no real world application.

I'm not aware of any published studies on the particular subject of hills holding potential for greater fuel economy. It's simply a derivative idea of the facts you're already aware of regarding ICE efficiency and the pulse and glide technique. The ascent up the hill forces a "pulse", a period of increased throttle opening where the engine operates most efficiently, followed by a glide down the hill where the engine is close to idle, or even in deceleration fuel cutoff mode. Of course, if the hill is too steep and the brakes are being heavily utilized, that isn't efficient. The other consideration is that the shortest distance between the start and end location is a straight line, so hills represent a longer distance between those points.

I've shared this graphic before, which I don't expect anyone to understand until they've stared at it for half an hour like I have. It's an efficiency heatmap for a particular engine, which all engine manufacturers have.

It shows lbs of fuel consumed per horsepower output at various throttle and engine speeds. The lower the number, the more power is produced for a given rate of fuel, in other words, the more efficiently the engine operates. The peak efficiency for the engine is 75% of peak torque at 2,500 RPM. The interesting thing though is that the engine is still quite efficient when the throttle is wide open, pretty much throughout the usable RPM range. All of the low efficiency represented by the purple and blue bands are associated with low engine load (light throttle).

You're right though that extreme hypermiling has no practical application in most situations because only a jerk pulse and glides in traffic. That's the beauty of many hybrid designs like the Prius, that they have mostly automated the hypermiling techniques and made them transparent to the driver while not requiring the car to actually pulse and glide to achieve it. The engine shuts off when slowly cruising or coasting, precisely where it's very inefficient to operate.

EVs take even more of the hypermiling strategy off the table because they are just so darned efficient from the get-go. There's not much to do to increase range other than drive slower, inflate the tires more, and micromanage the HVAC (including preconditioning). Aerodynamic improvements can be made, but small changes result in small difference and major alterations cause major difference. How extreme does one want to get? Having a cargo box on the hitch *may improve aerodynamic properties a little.

Much outside of that, and I start to consider things to be more ritual. Maybe praying to Saint Christopher for higher efficiency helps, but you aren't likely to see any measurable difference.

 

[evtinker]

One minor source of drag that impacts range, is steering inputs. Every change from straight ahead produces a slight amount of additional drag, both from the front tires, and I suppose to a microscopic amount, added aerodynamic drag on the body. I have ridden with a lot of drivers who seem to constantly make steering corrections, usually slightly too much, so they are effectively see-sawing the steering wheel continuously. Instead, I try to use extremely gentle almost imperceptible deflections, and being that the Bolt is so narrow, allow a few inches more drift off absolute center in the lane. Still nowhere near the edges of the lane, and certainly not far enough off to even be noticed by most other drivers, but no need to make a correction that isn’t actually needed. How much does this help? Who knows, but it can’t hurt.

One other way to increase range is to simply leave a little earlier. More available travel time means less reason to push a little harder, more ability to allow a little more following distance to allow more reaction time so fewer turning or braking events are needed. It also has the advantage of reducing stress.

 

[LighteningBug]

Good point! A front end alignment can help sometimes also

 

[efbolt]

But L mode does nothing for efficiency.
You are always in control of the accel and decel rates regardless of L or D modes.
The Brake Pedal is a variable Regen Pedal, until max regen is reached, then friction brakes blend in.

I use L mode and the paddle to regenerate as I near a stop light or stop sign as opposed to coasting in D.

There's regen in D too but it's light and I don't want to be a nuisance to other cars.

 

[Packard V8]

There's regen in D too but it's light and I don't want to be a nuisance to other cars.

Back to the Bolt introduction in 2016, the choice of D as the default mode was to make the Bolt driving experience as close to ICEs as possible. The goal was for a test drive to feel "normal." Once one becomes accustomed to the EV experience, many choose to double-click L for most situations.

FWIW, we had an older female friend who'd owned her Bolt for a couple of years. Riding with her, I noticed she used D and mentioned we always us L. She had never been told/shown L existed as a choice. Once she tried L, "It's like a whole new, better car. Thank you!"

jack vines

 

[GJETSON]

EVs take even more of the hypermiling strategy off the table because they are just so darned efficient from the get-go.

And the real improvements need to be done by the engineers back at the start. Check out these two Lucid tech videos. Tesla is top dog right now, but this former Tesla guy shows what it will take to really compete.

Under-battery aero design.

Look at the three looong orange phase wires from the inverter to the motor under the hood of a Bolt. Then check out the Lucid vs Tesla connections.

It is worth watching the motor video for the differential alone!!

 

[NortonCommando]

I use L mode and the paddle to regenerate as I near a stop light or stop sign as opposed to coasting in D.

There's regen in D too but it's light and I don't want to be a nuisance to other cars.

What said was "If the accel and decel rates are the same, there is no difference in efficiency using D or L."
You can have the exact same 'slow down rates' in D using the Variable Regen Brake Pedal and NOT use the Brake pads.

D or L are just personal driving style preferences. No difference in efficiency.

I think some Bolt owners seem to think they are using up the Brake Pads anytime they touch the Brake Pedal.
The Bolt has Blended Brakes. Tesla's do not.
With Brand T if you touch the old school Brake Pedal you are using up the pads.

 

[redpoint5]

And the real improvements need to be done by the engineers back at the start. Check out these two Lucid tech videos. Tesla is top dog right now, but this former Tesla guy shows what it will take to really compete.

Under-battery aero design.

View attachment 47139

Look at the three looong orange phase wires from the inverter to the motor under the hood of a Bolt. Then check out the Lucid vs Tesla connections.

It is worth watching the motor video for the differential alone!!

Excellent vids!

The interesting thing to me in the battery video was the cooling strategy conversation. Side cooling presents a shorter path for heat to transfer, but heat doesn't conduct as efficiently through the layers to the side. Not only that, but the cooling becomes more complex with the ribbon snaking between the cells, and the poor contact made with curved shapes. Contrast that with the longer heat path of top cooling, but the greater thermal conductivity through the length of the cell, the better contact with a flat surface, and simplicity of design. Then there was the safety consideration. With top cooling, the coolant acts as a barrier to the occupants above, giving more time for them to exit should thermal runaway occur.

Learned a lot more with the motor videos. The question begged though is given similar production volumes, what would be the unit cost of each design? Cost wasn't mentioned at all, but Lucid seemed to have a superior design from an engineering standpoint. Who knows what production challenges that design introduce? I like their attention to detail though. It always annoys me when, as a know-nothing nobody, I can identify process or design inefficiencies. When it's an experts job to design a small part of a system, they had better not miss something an ignorant person could get. There wasn't a single thing I could think to improve in their motor design, not that I could have improved Tesla's or any other manufacturers design.

Of course, this is all coming from a single perspective motivated to sell their cars. We could hear a debate between competing engineers to get a more full pro/con understanding of the tradeoffs of each design choice.

 

[efbolt]

What said was "If the accel and decel rates are the same, there is no difference in efficiency using D or L."
You can have the exact same 'slow down rates' in D using the Variable Regen Brake Pedal and NOT use the Brake pads.

D or L are just personal driving style preferences. No difference in efficiency.

I think some Bolt owners seem to think they are using up the Brake Pads anytime they touch the Brake Pedal.
The Bolt has Blended Brakes. Tesla's do not.
With Brand T if you touch the old school Brake Pedal you are using up the pads.

I know that the Bolt's brake pedal regens, but I didn't know that about Tesla's don't.

I didn't say L is more efficient than D though. I'm talking more about use of regen though as a convenience. Hypermilers have pointed out that avoiding regen gets better efficiency. In short, I prefer to regen and do so with L/paddle. The efficiency difference doesn't matter much to me.

 

[GJETSON]

Excellent vids!

Yeah. They made battery packs for the Formula E cars for several years. Racing is a great for learning what works.

And their motor...putting the differential inside the motor, before the reduction step, was brilliant. It made for a much smaller dif, and even though that requires a reduction gear on either end, they still ended up with no more gear mass, than the Bolts two step reduction setup. The entire motor manufacturing process is automated, so I doubt it is any more costly to build than the Bolt's motor, except perhaps for the cost of better materials. I'll gladly pay for better materials.

 

[MisterJJ]

I'll gladly pay for better materials.

That's awfully capitalist of you. 😉

 

[GJETSON]

That's awfully capitalist of you. 😉

I also gladly pay for union made stuff. F_ck the capitalist pigs.