Model 3 Efficiency - so bad...

[SageBrush]

We can't do much about #2, but we have some control over #1. What I've noticed is that with the Model S and Gen1 UMC, when charging at max 40A, my voltage drops to around 237V. I do have a bit of a long run of 6-3 Romex (150ft), so I think that's part of my issue. However, if I drop the current down to 32A or lower, my voltage increases to around 242V. So I sacrifice a bit on charge time, but I significantly reduce resistance in the wire. That's a 5V delta, times 40A = 200W of wasted power right there.

Very true, but you spend less time charging at the higher Amp rate so the actual percentage loss difference is 1.25x less. You lose about 2% of voltage at the higher Amp rate. More generally, if your resistance losses are r at an Amperage a, an increase of x percent in amperage will increase r losses by the same fraction.

For my uses, I find 32 A to be fine but my EVSE supports 40 A should the occasion arise.

 

[SageBrush]

I think the answer is yes. The range estimate is supposed to include real-world driving considerations, such as a mix of city and highway driving, traffic, navigation, etc. So to the extent that regen happens during normal driving, it's baked into the overall range number. People will squabble over which type of range estimate is more realistic, or matches their personal situation, but it's intended to be representative of the real world using the car as designed and built.

You are on the right track but it has nothing to do with 'real world.' The question is whether the test cycles used by the EPA in calculating range have deceleration segments that require friction brake use in a normal car and thus regen use in an EV. The answer is yes.

 

[DrLegoHair]

Getting similar numbers here too

 

[nvx1977]

@novox77 , are you using heating ?
Any idea what fraction of your ~ 200 Wh/mile is heating related ?

Nothing wrong with 200 Wh/mile, but honestly I'm surprised it is not better unless heating is involved. That, or the city driving killed your average ;-)

I expect the Model 3 to closely track my experience with my Prius Prime. In nice conditions and slow 30 mph driving in town my round trips average ~ 130 Wh/mile (7-8 miles per kWh.) Once I saw 110 Wh/mile for a round trip.

By the way, your photo is incriminating. It shows what time you left work ;-)

My friend has a Prius Prime and is also getting some insane efficiency on it. I'm not sure the 3 is capable of numbers that low. I just did a quick curb weight google search and the 3LR is about 500lb heavier than the Prius'. That extra weight goes toward giving the 3 its performance aspect (and range).

Haha, yes, I left work at 2:46pm. But you don't know what time I got to work in the morning
Ok who am I kidding. you got me.

 

[SageBrush]

I just did a quick curb weight google search and the 3LR is about 500lb heavier than the Prius'. That extra weight goes toward giving the 3 its performance aspect (and range).

The extra mass has very little effect on steady speed driving.
The extra friction is
mass - 230 Kg
RR - say 9/1000
G - 9.8

= 230*9.8*9/1000 = 20 Newtons
So about 32000 Joules per mile, or another 8.9 Wh/mile

 

[nvx1977]

The extra mass has very little effect on steady speed driving.
The extra friction is
mass - 230 Kg
RR - say 9/1000
G - 9.9

= 230*9.8*9/1000 = 20 Newtons
So about 32000 Joules per mile, or another 8.9 Wh/mile

Hills make a difference as well. I only know this because of the cycling in triathlon. We're all obsessed with watts per kg of bodyweight, but when the course is flat, heavier people always have the advantage, and it's all about power and less about bodyweight. It's like you say: their extra bodyweight doesn't make much difference in terms of load, but they can generate more power than lighter people, so they go faster. But once it gets hilly, bodyweight matters more, and the lighter riders gain the upper hand.

 

[jkirkwood001]

My friend has a Prius Prime and is also getting some insane efficiency on it. I'm not sure the 3 is capable of numbers that low. I just did a quick curb weight google search and the 3LR is about 500lb heavier than the Prius'. That extra weight goes toward giving the 3 its performance aspect (and range).

Haha, yes, I left work at 2:46pm. But you don't know what time I got to work in the morning
Ok who am I kidding. you got me.

Just guessing, but is the Prime efficiency being supplemented by the ICE? We know the Model 3 has practically the lowest wind resistance of any car, so hard to understand it being less efficient assuming same acceleration.

 

[jtri]

Hills make a difference as well. I only know this because of the cycling in triathlon. We're all obsessed with watts per kg of bodyweight, but when the course is flat, heavier people always have the advantage, and it's all about power and less about bodyweight. It's like you say: their extra bodyweight doesn't make much difference in terms of load, but they can generate more power than lighter people, so they go faster. But once it gets hilly, bodyweight matters more, and the lighter riders gain the upper hand.

Great analogy, I also race triathlon and am a big heavy guy. I can hang with anyone on the flats, but hills kill me. I drove my 3 235 miles on the 7th out to western mass and back on the 7th. When I started I had 312 miles of range got home with 60 miles in the tank.This car rocks!

 

[Electroman]

OP - not sure if this was answered: did you have heating on? what was the temp setting?

 

[nvx1977]

OP - not sure if this was answered: did you have heating on? what was the temp setting?

Cabin temp was set at 70 degrees. But it was barely running for most of the trip, fan speed at 1 out of 10. This car retains heat way better than my S. A much better sealed envelope. I turned the HVAC off about 1/4 of the way on the return trip. That's probably why the return trip shows better efficiency in that pic, despite the return trip gaining elevation.

 

[SageBrush]

Just guessing, but is the Prime efficiency being supplemented by the ICE?

Nope.
Cd is the same; I'm not sure about frontal area. The EPA MPGe results are quite similar

 

[SageBrush]

Cabin temp was set at 70 degrees. But it was barely running for most of the trip, fan speed at 1 out of 10. This car retains heat way better than my S. A much better sealed envelope. I turned the HVAC off about 1/4 of the way on the return trip. That's probably why the return trip shows better efficiency in that pic, despite the return trip gaining elevation.

Yeah...
Between this energy use and warmer air, you will see much better results in a month.

 

[Cheri R]

im new to Tesla- took my performance m3 on its first long trip and barely made it to the charging station - burned 270 battery miles in a 150 miles of highway driving. Is this normal? Admittedly I’m a speed demon and drove it at 82 mph on cruise- but was really surprised how quickly it burned thru the battery? Any info would be appreciated???
...
... bad to the bone.

Full context: this is my daily commute from southern New Hampshire into Boston, Massachusetts, which is about an 80-mile round trip. Most of it is along Interstate 93, so I'm using Enhanced AutoPilot most of the way. No hypermiling techniques here, just the car's AI. I'm halfway home when the picture was taken. Morning temp was 35F. Return trip was 42F.

The traffic actually helps efficiency since there's little aerodynamic drag, and there's lots of regeneration going on. Perfect little commuting car, this Model 3. And EAP works so well in these kind of traffic conditions.[/QUOTE]

 

[ecarfan]

Electrons have mass! His car is lighter and therefore takes less energy to push it forward!

For sure. At 9.11 × 10-28 grams per electron, they really add up!

 

[Cheri R]

Hi I’m new to Tesla. I took my performance M3 on its first long road trip out across the Mojave desserts I-40 fwy. Now admittedly I’m a speed demon and averaged about 82mph- but I burned up 270 battery miles in about 150 hwy miles. Is this normal? I was expecting better mileage then this? Any help would be appreciated??

 

[Seattle]

Hi I’m new to Tesla. I took my performance M3 on its first long road trip out across the Mojave desserts I-40 fwy. Now admittedly I’m a speed demon and averaged about 82mph- but I burned up 270 battery miles in about 150 hwy miles. Is this normal? I was expecting better mileage then this? Any help would be appreciated??

The amount of energy used driving is proportional to the cube of the speed so yes, you use a lot more energy going 82 than 70. The strange phrase people use is sometimes driving slower goes faster because you need less charging.

Your other message about low temps also could indicate something. When it's really cold the batteries are heated, that wastes some energy. You'll go much faster if you heat the batteries before you, by charging them. My S has an option for warming things up before i get in the car. You should look at the gauge of energy usage. driving so fast could it be that you are kind of pointlessly driving fast up at the start? The increase of energy usage in gas cars isn't so visible since they aren't so accurate.

 

[Jeffers0n]

Hi I’m new to Tesla. I took my performance M3 on its first long road trip out across the Mojave desserts I-40 fwy. Now admittedly I’m a speed demon and averaged about 82mph- but I burned up 270 battery miles in about 150 hwy miles. Is this normal? I was expecting better mileage then this? Any help would be appreciated??

You’ll get about 15% worse range from your 20” tires vs 18” Aeros off the bat. Plus AWD gets less range vs RWD.

 

[nvx1977]

Yeah...
Between this energy use and warmer air, you will see much better results in a month.

I confirmed this via other threads (as you know). Once ambient temps got above 60F, efficiency went thru the roof. That same commute in my OP turned into 165Wh/mi average. At the peak of summer with A/C running, it was closer to 200Wh/mi.

Right now the conditions match when I took delivery of the car. In another couple of months, we'll see what kind of toll ~0F weather will do to efficiency and regen.

 

[Atari2600]

Following a semi on autopilot I was able to do 70 MPH under 230 Wh/mi. My dual motor is normally between 280 to 300 Wh/mi at that speed. I plan on using autopilot behind a big box van to see how it goes. The speed limit is 70 and I normally set the speed at 75 or so. I thought about trying to close the gap up another car length or so to see what would happen but decided against being an ass.