Range efficiency: Spec vs Reality

[CowherPower]

On our 2020 Model Y Long Range awd, we only get 70- 75% range efficiency.
That is to say, if we charge up to 280 miles, and deplete if down to 80 miles stated range, we only have driven 140-150 miles. So let’s call that 75% avg efficiency.

I'm seeing even worse on my 2021 Model Y (around 70% range compared to what the car predicted). I know there are a ton of variables and that you need to have a perfect situation to get anywhere close to the expected range, but 70% seems crazy low to me. The weather is warm outside (low 90s), the car is in my garage most of the day (low 70s), I don't have Sentry mode enabled at home, and I'm not going too crazy (well maybe just a little) with the amazing acceleration on the car. So should I just expect 70% efficiency (or worse in the winter) for the life of the car?

One thing I wonder about is that the car almost always seems to have a fan on under the hood. I know this is normal after a drive while it's cooling the battery down, but I frequently go into the garage late at night when it's 70 degrees outside and the car hasn't been driven in hours and that fan is still going. The climate control in the car is NOT on, so I have no idea why that fan runs so much. But if I use the Tesla app to wake the car up and purposely turn the climate on and then off, the fan stops. Very weird.

 

[jsight]

I'm seeing even worse on my 2021 Model Y (around 70% range compared to what the car predicted). I know there are a ton of variables and that you need to have a perfect situation to get anywhere close to the expected range, but 70% seems crazy low to me. The weather is warm outside (low 90s), the car is in my garage most of the day (low 70s), I don't have Sentry mode enabled at home, and I'm not going too crazy (well maybe just a little) with the amazing acceleration on the car. So should I just expect 70% efficiency (or worse in the winter) for the life of the car?

One thing I wonder about is that the car almost always seems to have a fan on under the hood. I know this is normal after a drive while it's cooling the battery down, but I frequently go into the garage late at night when it's 70 degrees outside and the car hasn't been driven in hours and that fan is still going. The climate control in the car is NOT on, so I have no idea why that fan runs so much. But if I use the Tesla app to wake the car up and purposely turn the climate on and then off, the fan stops. Very weird.

Could you have a monitoring app running that is keeping the car from sleeping?

It would be unusual for a fan to run while the car is actually asleep.

 

[jcanoe]

Short distance driving is less efficient. You waste energy either warming the battery pack and passenger cabin (in winter) or cooling the battery pack and passenger cabin (in summer.) In moderate temperatures the car does not have to warm or cool the battery, just circulate the coolant. In the passenger cabin you only need to use the fan to be comfortable.

 

[TomServo]

Trip Computer info from a recent road trip from southern IL to southern MD vis I-64.

It was HOT and HUMID during the trip, I didn't use my Aero Caps. I did set my tire pressure to 44 psi COLD and my TACC offset to 5 over. We encountered about 2200 feet of elevation changes along the way.

Based on back of the napkin math I calculate had I charged to 100% and driven the battery to empty (no one really does that) I could have gone about 265 miles on ONE FULL charge. My 2020 Y was EPA rated at 316 miles. That's about an efficiency rating of 83% I'm not complaining.

 

[jcanoe]

Trip Computer info from a recent road trip from southern IL to southern MD vis I-64.

It was HOT and HUMID during the trip, I didn't use my Aero Caps. I did set my tire pressure to 44 psi COLD and my TACC offset to 5 over. We encountered about 2200 feet of elevation changes along the way.

Based on back of the napkin math I calculate had I charged to 100% and driven the battery to empty (no one really does that) I could have gone about 265 miles on ONE FULL charge. My 2020 Y was EPA rated at 316 miles. That's about an efficiency rating of 83% I'm not complaining.

My Model Y was delivered in the middle of June '20. I'm seeing the same results; lifetime Wh/mi of 267, estimated total range ~270 miles vs 316 EPA (84%).

I received a document from Tesla when I purchased my Model Y that stated the battery capacity was 74 kWh. This document was provided so I could apply for a Maryland tax rebate program. (By the time I took deliver of my Model Y the Maryland tax rebate program was depleted of funds for 2020. The Maryland legislative did not vote to fund the program in 2021.)

 

[angus[Y]oung]

Based on back of the napkin math I calculate had I charged to 100% and driven the battery to empty (no one really does that) I could have gone about 265 miles on ONE FULL charge. My 2020 Y was EPA rated at 316 miles. That's about an efficiency rating of 83% I'm not complaining.

@TomServo yeah considering like this was a road trip [at presumably mostly highway speeds] and through hot/humid weather, and also you had your aero caps off (which reportedly makes for about 10% worse range at highway speeds), this doesn't sound bad at all.

 

[CowherPower]

One thing I wonder about is that the car almost always seems to have a fan on under the hood. I know this is normal after a drive while it's cooling the battery down, but I frequently go into the garage late at night when it's 70 degrees outside and the car hasn't been driven in hours and that fan is still going. The climate control in the car is NOT on, so I have no idea why that fan runs so much. But if I use the Tesla app to wake the car up and purposely turn the climate on and then off, the fan stops. Very weird.

Could you have a monitoring app running that is keeping the car from sleeping?

It would be unusual for a fan to run while the car is actually asleep.

Nope, I'm not using any kind of monitoring app (unless you count the regular Android Tesla app which always shows up in my notifications as "Connected"). Tonight I went out to the garage four times and the fan under the hood was running every time. The temperature outside was only 78 degrees and the car hadn't been driven for hours, so the battery should have been cool. Each time all I had to do was briefly open the driver's side door and close it and the fan would stop. Why does the fan keep running so much and why does opening/closing the door make it stop? This has to be taking a toll on my range efficiency.

 

[jcanoe]

You could try performing a soft reset. If that does not stop the fan from running then try a hard reset.

 

[CowherPower]

You could try performing a soft reset. If that does not stop the fan from running then try a hard reset.

Thanks. Great idea, but sadly power cycling the car (Controls/Safety/Power Off) didn't seem to solve the problem. The fan keeps kicking back on for some reason. Opening/closing the door stops it for a while, but if I come back 10 minutes later, the fan is back on. Kind of driving me crazy, but not sure I'm ready to try a hard reset yet.

 

[jcanoe]

Open a service request in the Tesla app. Describe what is happening re the fan staying on.

 

[GtiMart]

The cabin heating/cooling fan will run for an hour or more after you have driven the car if you used the AC, to dry out the evaporator in an attempt to prevent bad odors. Opening the door will stop this.
Cabin overheat protection will monitor interior temperature and run the AC or fan if temp goes above 105F. It's surprising how interior temp goes up quickly if there's any kind of sun hitting the car. This will even wake the car up if it's sleeping. There's a setting to turn it off if you want to.
Otherwise the car's BMS will run the cooling for the battery any time it thinks it's required.

 

[jcanoe]

In Virginia it would be rare for the temperature inside a garage to exceed 105F, maybe 100F but not higher. The after blow setting for the HVAC system only runs the fan for ~20 minutes, not for hours.

 

[GtiMart]

...then there's another reason why my fan was running more than an hour after my drive, inside my garage, sometimes. And it was not cabin overheat as you point out.
There are specific conditions where my car stays "on" after I get out of it, like if I just move it in the driveway without using my seatbelt. In those cases the AC fan would continue forever. It's easy to spot though as my daytime running lights are on when I get out of the car. I just open/close the driver's door and it stops. That is some kind of bug in the software, or my seat weight sensor is partly defect. Maybe you have this behavior too?

 

[Pianewman]

Whines/clicks/buzzes/fan on and off...I've been dealing with these issues since my first (UGH!) hybrid, an early Toyota Camry. I've learned to simply acknowledge them and then ignore them. I honestly don't know how any of us, w/o diagnostic equipment, can possible determine when something is faulty.

...except a cooling fan that runs constantly in 70f ambient temps...

 

[Big Earl]

...then there's another reason why my fan was running more than an hour after my drive, inside my garage, sometimes. And it was not cabin overheat as you point out.
There are specific conditions where my car stays "on" after I get out of it, like if I just move it in the driveway without using my seatbelt. In those cases the AC fan would continue forever. It's easy to spot though as my daytime running lights are on when I get out of the car. I just open/close the driver's door and it stops. That is some kind of bug in the software, or my seat weight sensor is partly defect. Maybe you have this behavior too?

I have that behavior in my Model 3. If I just hop in and move the car a short distance without buckling my seatbelt, it stays on until I open and close the door again. At least that seems to be what triggers it - it happens so infrequently that I hadn't established a pattern until you mentioned it.

 

[frankvb]

...then there's another reason why my fan was running more than an hour after my drive, inside my garage, sometimes. And it was not cabin overheat as you point out.
There are specific conditions where my car stays "on" after I get out of it, like if I just move it in the driveway without using my seatbelt. In those cases the AC fan would continue forever. It's easy to spot though as my daytime running lights are on when I get out of the car. I just open/close the driver's door and it stops. That is some kind of bug in the software, or my seat weight sensor is partly defect. Maybe you have this behavior too?

That's a good idea to check that - in my Y the seat weight sensor was indeed working intermittently, and sometimes the screen stayed on when exiting the vehicle and closing the door (and the vehicle would not lock when walking away).

 

[CowherPower]

Ok, I'm throwing in the towel and submitting a service request to have them try and figure out why the fan under my 2021 Model Y's hood runs almost constantly. I've been pulling out my hair all day (and I don't have that much to begin with) running various tests to see if any combination of changes will stop the fan from kicking in. So far, no luck. In case anyone else is having a similar problem and is curious, here are just a few of the things I've tried:

• Performed a soft reboot/restart of the car (Controls/Safety/Power Off)
• Turned off the climate system
• Turned off Sentry mode
• Turned off cabin overhead protection
• Shut my phone down (in case the Tesla app was keeping the car awake). I have no third-party monitoring apps.

There's no way the car needs the fan to cool things down. The car hasn't been driven for over 6 hours and it's only 73 degrees outside. The battery is not being charged (and hasn't been charged for probably 4 days).

I took the panel off under the hood and the fan that is kicking in is the one that draws air into the big intake on the passenger side. This is so weird since I have shut down the climate control system (and cabin overheat protection). I'm sure most of you know the intake that I'm talking about, but I've included a picture anyway.

I'm open to other suggestions. My expected range clicks down by 1 mile every few hours and I'm guessing it's because of this.

 

[Big Earl]

Ok, I'm throwing in the towel and submitting a service request to have them try and figure out why the fan under my 2021 Model Y's hood runs almost constantly. I've been pulling out my hair all day (and I don't have that much to begin with) running various tests to see if any combination of changes will stop the fan from kicking in. So far, no luck. In case anyone else is having a similar problem and is curious, here are just a few of the things I've tried:

• Performed a soft reboot/restart of the car (Controls/Safety/Power Off)
• Turned off the climate system
• Turned off Sentry mode
• Turned off cabin overhead protection
• Shut my phone down (in case the Tesla app was keeping the car awake). I have no third-party monitoring apps.

There's no way the car needs the fan to cool things down. The car hasn't been driven for over 6 hours and it's only 73 degrees outside. The battery is not being charged (and hasn't been charged for probably 4 days).

I took the panel off under the hood and the fan that is kicking in is the one that draws air into the big intake on the passenger side. This is so weird since I have shut down the climate control system (and cabin overheat protection). I'm sure most of you know the intake that I'm talking about, but I've included a picture anyway.

I'm open to other suggestions. My expected range clicks down by 1 mile every few hours and I'm guessing it's because of this.

Have you done the two finger salute, AKA holding both scroll wheels to reset the infotainment computer? I'd say this is probably the first step you should take, but in your post yesterday, you said you were reluctant to do it.

Seems like you've already figured it out, but the fan that's running is the cabin climate control fan, which has no function with regard to battery cooling.

 

[CowherPower]

Have you done the two finger salute, AKA holding both scroll wheels to reset the infotainment computer? I'd say this is probably the first step you should take, but in your post yesterday, you said you were reluctant to do it.

Seems like you've already figured it out, but the fan that's running is the cabin climate control fan, which has no function with regard to battery cooling.

Oh I have no problem resetting the invotainment system, but I figured the soft reboot of the car that I did (Controls/Safety/Power Off) already did that (and more). But I can try rebooting just the screen to see if that does anything. The thing that I was reluctant to try was the hard reset where you power down the car and then physically disconnect the 12-volt battery. I'm not ready to try that yet.