Is 320 miles on ER possible? Not seeing it in the math...

[RickLightning]

I wasn't remarking about the efficiency of one gear, or lack of efficiency.

You compared backroads driving and highway driving. In backroads driving, you stated the advantage of regenerative braking, but then you stated that on the highway EVS get hit with air resistance and lack of gearing, which is why they get lower efficiency as compared to backroads driving.

I'm saying that on the highway, you're not getting regenerative braking as compared to backroads, plus you're driving much faster which uses much more energy (the air resistance). The lack of gearing would be a much smaller impact in the scheme of things, at least to this non-engineer.

Of course ICE vehicles don't "shine" anywhere. But they do get more miles per gallon on highway than city, which is the opposite for hybrids, PHEVs, and EVs.

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[greenne]

I wasn't remarking about the efficiency of one gear, or lack of efficiency.

You compared backroads driving and highway driving. In backroads driving, you stated the advantage of regenerative braking, but then you stated that on the highway EVS get hit with air resistance and lack of gearing, which is why they get lower efficiency as compared to backroads driving.

I'm saying that on the highway, you're not getting regenerative braking as compared to backroads, plus you're driving much faster which uses much more energy (the air resistance). The lack of gearing would be a much smaller impact in the scheme of things, at least to this non-engineer.

Of course ICE vehicles don't "shine" anywhere. But they do get more miles per gallon on highway than city, which is the opposite for hybrids, PHEVs, and EVs.

I do think its important to remember regenerative braking is not a "good thing" compared to not braking at all. Its still taking one form of energy(kinetic) and transferring it into another form of energy. As with any transformation(conversion) there will be losses... maybe negligible. (Law of conservation of energy)

However all other things being equal one shouldn't strive to be slowing down/speeding up just so they regenerative brake--if there is no other reason to do so. You'll lose energy due to transformation loss

That said, of course you would have to weigh the losses due to regenerative braking/speeding up vs the losses due to increased wind resistance at highway speeds. But if you were to compare speeding up/slowing down on a backroad to the same avg speed on the highway--the highway would be more efficient.

 

[cvalue13]

You compared backroads driving and highway driving. In backroads driving, you stated the advantage of regenerative braking, but then you stated that on the highway EVS get hit with air resistance and lack of gearing, which is why they get lower efficiency as compared to backroads driving.

I'm saying that on the highway, you're not getting regenerative braking as compared to backroads, plus you're driving much faster which uses much more energy (the air resistance). The lack of gearing would be a much smaller impact in the scheme of things, at least to this non-engineer.

I’m confused, then, about your apparent disagreement with what I said.

Because, I too said that a reason EVs are more efficiency than ICE in back roads driving is because of the regenerative breaking (where ICE has none), and that further EVs are even less efficiency than ICEs at highway speeds due to EV’s lack of gearing. The point, then, the ways in which EVs are more efficient than ICE’s in back roads stop-and-go driving and less efficient (relatively speaking) at highway speeds due to lack of gearing.

And while I don’t have specific data to back it up, I think you would be mistaken to believe that lack of gearing has an immaterial impact on efficiency. From the article on the Cayman with the first two-speed EV: “Having a multispeed transmission in an EV provides the same benefits that it does in a gasoline-powered car: improved low-speed acceleration and increasedefficiency at high velocity by lowering the rotating speed of the power source. In other words, the ratio spread of the two-speed transmission will help the Taycan's highway driving range while also making it quicker. … At highway cruising speeds, which is usually EV kryptonite, the tall top gear should boost the Taycan's range, although Porsche has yet to announce EPA range ratings.”

As for air resistance: Both EVs and ICE vehicles (that are shaped similarly) have equal efficiency issues due to air resistance at higher speeds, so air resistance has essentially nothing to do with the differences in efficiency between ICE and EVs. For both, as speed increases, air resistance increases, and efficiency deteriorates. (This is why both ICE and EV vehicles have higher efficiency at 55mph than they do at 85mph, e.g.)

So in all, if someone says “hey, why does my EV have better efficiency at low back road driving than highway driving” the answer is two-fold: regenerative breaking increases efficiency in back road driving, while at high speeds efficiency is reminisced by both air resistance and lack of top end gearing - and on both metrics, the faster, the worse the efficiency.

 

[sotek2345]

Ok, I will chime in here. Used to be an engineer (not automotive) before I went into management

Any vehicle has 2 categories of load. Load to operate the vehicle (i.e. keep it on), and load to move the vehicle.

For EVs, the load to operate the vehicle is very low, gets a little higher in the cold for heat but still way less than ICE. Because of this, the load to move the vehicle dominates and higher speed = less efficiency above a very small value (10 to 20 mph).

For ICE vehicles, you have a constant load to keep the engine running. That load is huge compared to an EV. Because of this, you have to be going much faster to overcome that and make movement loads dominate typically that is in the 45 to 55 mph range.

Gearing, regen breaking, etc. influence these factors, but the core difference remains the same.

 

[cvalue13]

I do think its important to remember regenerative braking is not a "good thing" compared to not braking at all.

right: regenerative breaking is a “good thing” to the extent that, absent regenerative breaking (like in an ICE), there is zero recoupment of energy loss through breaking.

that said…

But if you were to compare speeding up/slowing down on a backroad to the same avg speed on the highway--the highway would be more efficient.

this equivalence may be true, but it does not make immediate proof, to me. Why? Because any regenerative breaking at high speeds will be of reduced effectiveness due to the effects of air resistance. That is, the higher the speeds, the more air resistance is assisting the slowing, and so depriving the regenerative mechanics the opportunity to to recapture that energy. To some, surely marginal, degree - but still … not a 1-for-1 equivalence between low and high speed regenerative recoupment, I believe

 

[jredondox]

It’s possible if I keep it under 65 tho but the best I have gotten is 310 down to 2% charge

 

[cvalue13]

Ok, I will chime in here. Used to be an engineer (not automotive) before I went into management

Any vehicle has 2 categories of load. Load to operate the vehicle (i.e. keep it on), and load to move the vehicle.

For EVs, the load to operate the vehicle is very low, gets a little higher in the cold for heat but still way less than ICE. Because of this, the load to move the vehicle dominates and higher speed = less efficiency above a very small value (10 to 20 mph).

For ICE vehicles, you have a constant load to keep the engine running. That load is huge compared to an EV. Because of this, you have to be going much faster to overcome that and make movement loads dominate typically that is in the 45 to 55 mph range.

Gearing, regen breaking, etc. influence these factors, but the core difference remains the same.

Interesting addition, but I’m not completelygrasping the magnitude of the effect.

wouldn’t the effect you’re describing be relevant only when, eg, the vehicle is completely stopped (where the ICE is idoling but the EV is not), coasting (same dynamic), or breaking (same dynamic, if ignoring regen)?

if so, then the energy consumption for idoling in ICE vs EV makes straightforward sense as being one of several differences in efficiency, but does not to me make straightforward sense as being the predominant delta compared to regen, gearing, etc.)

interested to learn more

 

[sotek2345]

Interesting addition, but I’m not completelygrasping the magnitude of the effect.

wouldn’t the effect you’re describing be relevant only when, eg, the vehicle is completely stopped (where the ICE is idoling but the EV is not), coasting (same dynamic), or breaking (same dynamic, if ignoring regen)?

if so, then the energy consumption for idoling in ICE vs EV makes straightforward sense as being one of several differences in efficiency, but does not to me make straightforward sense as being the predominant delta compared to regen, gearing, etc.)

interested to learn more

No - it takes a certain amount of energy to keep the ICE engine spinning at all times (minor exception for breaking if it has decel fuel cut off). Driving actually takes more than idle due to drivetrain losses through the transmission.

 

[cvalue13]

No - it takes a certain amount of energy to keep the ICE engine spinning at all times (minor exception for breaking if it has decel fuel cut off). Driving actually takes more than idle due to drivetrain losses through the transmission.

sorry for being a dunce, but appreciate the hand-holding towards understanding:

whatever is the “certain amount of energy to keep the ICE engine spinning at all times” will ultimately be reflected in fuel consumption. and it is that fuel consumption by which we are then gauging relative efficiency. That “certain amount of energy to keep the ICE engine spinning” is, is it not, essentially idoling fuel consumption?

feel like I’m taking crazy pills

and btw, I’m allowing for keeping things simple here because if we were really drilling down I’d be asking not only about EC vs ICE efficiencies at the engine/motors, but also regarding the broader need for energy consumption at the accessories and cooling being used by EV vs ICE.

despite the fact that my EV is not idoling fuel when stopped, coasting, breaking, as in my ICE, my current gut feeling (admittedly) is that the EV is less efficient than my ICE at running the accessories/cooling during an idol (be it sitting, breaking, coasting).

here’s my past two days (with a substantial amount of idoling while sitting), in my EV:

that is 43% (!!!) of my EV’s energy consumption going towards this “idoling” energy WITHOUT spinning the motors

I would find it VERY hard to believe that my ICE dual consumption in similar conditions would be 43% towards climate, accessories, and certainly not towards battery conditioning.

accordingly, while I’m beginning to grasp the assertion that EVs are more efficient relative to ICE’s insofar as not needing to idol the engine, it is still hard for me to believe that this is a material component of the EV’s efficiency (compared to regen, fearing), and VERY hard for me to believe that the ICE devotes nearly as much fuel to running the non-driving systems of the vehicle

 

[RickLightning]

I give up.

 

[sotek2345]

sorry for being a dunce, but appreciate the hand-holding towards understanding:

whatever is the “certain amount of energy to keep the ICE engine spinning at all times” will ultimately be reflected in fuel consumption. and it is that fuel consumption by which we are then gauging relative efficiency. That “certain amount of energy to keep the ICE engine spinning” is, is it not, essentially idoling fuel consumption?

feel like I’m taking crazy pills

and btw, I’m allowing for keeping things simple here because if we were really drilling down I’d be asking not only about EC vs ICE efficiencies at the engine/motors, but also regarding the broader need for energy consumption at the accessories and cooling being used by EV vs ICE.

despite the fact that my EV is not idoling fuel when stopped, coasting, breaking, as in my ICE, my current gut feeling (admittedly) is that the EV is less efficient than my ICE at running the accessories/cooling during an idol (be it sitting, breaking, coasting).

here’s my past two days (with a substantial amount of idoling while sitting), in my EV:

that is 43% (!!!) of my EV’s energy consumption going towards this “idoling” energy WITHOUT spinning the motors

I would find it VERY hard to believe that my ICE dual consumption in similar conditions would be 43% towards climate, accessories, and certainly not towards battery conditioning.

accordingly, while I’m beginning to grasp the assertion that EVs are more efficient relative to ICE’s insofar as not needing to idol the engine, it is still hard for me to believe that this is a material component of the EV’s efficiency (compared to regen, fearing), and VERY hard for me to believe that the ICE devotes nearly as much fuel to running the non-driving systems of the vehicle

Ok, happy to help.

First - off the bat, 70% to 80% of the energy in gasoline is converted to heat and wasted. This is the vast majority of the reason EVs are more efficient than ICE vehicles, but it does make ICE vehicles more efficient at heating the cabin than an EVs.

For other things (headlights, A/C, cabin features, etc.) it is basically a wash.

Now we can get into relative efficiency differences. Let's use constant speed operation. Regen will help in stop and go situations making EVs even better, but this holds true for constant speed anyways.

At 30mph, the EV will be more efficient than at 60mph. The aero drag at 60 is much higher than at 30 and it takes more energy to push through. This is the majority of energy usage at a constant speed since the operating loads are very low, basically just the "other things" mentioned above.

At 30mph, the ICE will be less efficient that it will at 60mph. Because of the various gearing an ICE has, the rpms can be about the same at both speeds. This means the loads to run the motor will be the roughly the same at either speed. These loads include, piston friction, moving valves, the oil pump, the cooling system, spark plugs, fuel pumps, etc. These loads take energy over time, so the slower you go, the more energy it takes per mile driven. They are high enough that the transition for most ICE vehicles is in the 45mph to 55mph range when the aero loads become dominating over the operating loads on a per mile basis.

 

[Roy2001]

Huh - I didn't see nearly that big of a loss at ~55F in our Mach-e. It really started dropping off below 30F and the largest impacts were in the -10F to -20F without preconditioning (departure time). I haven't experienced it, but other videos have shown it keeps dropping off down to at least -40F.

I will say that below ~10F or so, you can't really charge on a 120V circuit (L1). All of the energy just goes into keeping the battery warm.

When I said 55F it means 35F to 55F which is typical in Sacrament during winter.

 

[F150ROD]

Im no way shape or form will an EV be less efficient than an a similar ICE, you don’t have to baby it to get good range.

It’s no different than going full WOT +80mph and expecting to get the rated EPA range or go 400+ miles on a tank, it’s not going to happen…. Well at least in my 21 EB 2.7 it didn’t happen.

 

[cvalue13]

Im no way shape or form will an EV be less efficient than an a similar ICE, you don’t have to baby it to get good range.

if I misspoke or was unclear, forgive me - but I was never intending to suggest that an EV would would “more efficient” than a similar ICE on a gross basis

was instead only comparing the relative efficiencies an EV (compared against itself) does or doesn’t have vs an ICE (also compared against itself). E.g., all else equal an EV gets better net mileage “in town” than at sustained high speeds, while ICE’s tend to get worse net mileage “in town”

For other things (headlights, A/C, cabin features, etc.) it is basically a wash.

thanks for all that, helpful and interesting.

As for accessories being a wash, though, I’d be interested to see some comparisons on a relative bases - that is, how much of an EV’s utilized energy from a 100%-0% charge goes to climate/accessories/battery conditioning, vs how much of an equivalent ICE’s utilized energy from a full tank to empty goes to climate/accessories.

 

[sotek2345]

thanks for all that, helpful and interesting.

As for accessories being a wash, though, I’d be interested to see some comparisons on a relative bases - that is, how much of an EV’s utilized energy from a 100%-0% charge goes to climate/accessories/battery conditioning, vs how much of an equivalent ICE’s utilized energy from a full tank to empty goes to climate/accessories.

That would be interesting data and I don't know if I have seen anything explicit on that.

Let's look at accessories except A/C (since that is a little different). I would expect the EV to be slightly more efficient. All else being equal, the accessories themselves will pull the same power, so what we are really comparing is the efficiency of the HVB to LVB transfer to the efficiency of the Alternator. Google tells me that alternators are between 55% and 75% efficienct. The HVB to LVB transfer should be better than 90% efficient since it is DC to DC.

For the AC, this is powered by the HVB in an EV (relatively efficient) and via direct belt drive in an ICE, also pretty efficient. Not sure which would win.

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