AC killing mileage, defective heat pump?

[Djcmy]

I have about 600 miles on my. Mileage bad, had Tesla remote battery check, Tesla said all good. Mileage decreasing.

Took 6 mile test run. 50 mph via cruise control. Ac set at 71, fan speed 6. wh 341, projected range 150. Return trip same, but ac and fan off, wh 175, peojected range 381.

Is anyone experiencing ac effecting range by 50%?

 

[asa8080]

Y

I have about 600 miles on my. Mileage bad, had Tesla remote battery check, Tesla said all good. Mileage decreasing.

Took 6 mile test run. 50 mph via cruise control. Ac set at 71, fan speed 6. wh 341, projected range 150. Return trip same, but ac and fan off, wh 175, peojected range 381.

Is anyone experiencing ac effecting range by 50%?

Sure road absolutely flat to be identical back and forth? Besides 6 miles is too short as well as with 600 tostados BMS could still calibrating.
AC took 1-2kw when running (it was a video measuring which hvac option consumption)
That 20w/mi on high speed and 30-40 on low speed assuming 100% work time.

 

[Djcmy]

Y

Sure road absolutely flat to be identical back and forth? Besides 6 miles is too short as well as with 600 tostados BMS could still calibrating.
AC took 1-2kw when running (it was a video measuring which hvac option consumption)
That 20w/mi on high speed and 30-40 on low speed assuming 100% work time.

What is tostados bms? Road flat, eastern shore area. 1-2 kw over what, mileage, time? All new to me. What video are you referring to? Thanks!

 

[byeLT4]

I'm far from an expert but.. If the return trip was shortly after the initial trip it is my understanding that the battery may be up to 'operating temp' and that more power may be used on your initial trip to get battery to operating temp. To me your numbers are a huge variance but with only 6 miles to test their could possibly be other factors. I'm in an S but I know wind plays a big factor to the tune of about 50-70 Wh at 75mph with tailwind vs headwind.

 

[asa8080]

What is tostados bms? Road flat, eastern shore area. 1-2 kw over what, mileage, time? All new to me. What video are you referring to? Thanks!

Total 600 damn autocorrect I mean battery management system could show different ranges at that point still, better use w/mi usage.
Power is measured in kW. Running AC taking 1-2kw. If it would run fir an hour it would take 2kw from battery. Let say you drive 60mi/h and with 250wh/mi it would take 15kW for driving. AC will add 2000/60=~35w/mi so you’d get 285w/mi instead (17000w/60mi)
That your loss due to AC

The video I think I see from some other tread about low range, couldn’t find now

 

[Djcmy]

Total 600 damn autocorrect I mean battery management system could show different ranges at that point still, better use w/mi usage.
Power is measured in kW. Running AC taking 1-2kw. If it would run fir an hour it would take 2kw from battery. Let say you drive 60mi/h and with 250wh/mi it would take 15kW for driving. AC will add 2000/60=~35w/mi so you’d get 285w/mi instead (17000w/60mi)
That your loss due to AC

The video I think I see from some other tread about low range, couldn’t find now

Thanks again!

 

[mswlogo]

Bogus test.

Always test each condition with a round trip test.

Also first 5 miles, what’s that 5 minutes? AC could be working hard for first 5 miles to cool off cabin. Then very little to maintain it there after.

You need longer tests to eliminate some variables.

 

[Djcmy]

Ac was run 10 minutes before test. Road surface completely flat. Will do round trip, 12 miles, for more accuracy. Thanks!

 

[asa8080]

Ac was run 10 minutes before test. Road surface completely flat. Will do round trip, 12 miles, for more accuracy. Thanks!

Actually you can do more accurate test IMO, just need 5-10 miles of more or less straight road WITHOUT stops and without MUCH change in profile
1. Start a trip, set AC MANUAL, let say 70F fan speed 5. Drive on AP 50 or 60 (whatever speed limit) for 5 minutes, note the w/mi reading for it, W1.
2. Completely shut down AC AND fan (HVAC off). Continue driving for 5 more minutes. Note w/mi for THAT interval - W2.
Now your HVAC "inefficiency" would be Whvac=W2-W1 (should be in 20-40w/mi range for 60mi/h speed)

 

[rxlawdude]

I'm on a road trip now in Arizona (ambients around 104F), and my Wh/mi consumption is ridiculously high (310Wh/mi) compared to my average at (more temperate) home of 280Wh/mi (still not great).

It will be interesting to see when I get back home if the Wh/mi returns to baseline as expected.

By the way, this car is a sweet road tripper!

 

[Djcmy]

I'm on a road trip now in Arizona (ambients around 104F), and my Wh/mi consumption is ridiculously high (310Wh/mi) compared to my average at (more temperate) home of 280Wh/mi (still not great).

It will be interesting to see when I get back home if the Wh/mi returns to baseline as expected.

By the way, this car is a sweet road tripper!

What is your avg speed and what us ac set on?

 

[Mike MY]

The first several miles every time I drive the car have extremely high energy consumption. Even if I turn on the A/C using the app to pre-cool the car in advance. I suspect this is some type of battery conditioning at the start of every drive. After those first 3-5 miles energy consumption settles down to a reasonable value. I suspect the first leg of your 6 mile test suffered from this phenomenon.

I have 4,700 miles on my car now with a lifetime average of 257 Wh/mi. I’m quite happy with that performance.

I tried a test yesterday to see how much the A/C affected consumption. Driving on the interstate at 65 mph. I brought up the power consumption graph. 90 degrees outside. With the A/C set at 70 on auto the graph showed I was using about 255 Wh/mi. I then turned the temp down to 62 which caused the fan speed to increase significantly. The power graph barely changed (a little, but not a lot). This leads me to believe the A/C setting is not a huge contributor. I didn’t test it with the A/C turned off because turning off the A/C is not a realistic option for the real world. Hope this info is helpful.

 

[Djcmy]

The first several miles every time I drive the car have extremely high energy consumption. Even if I turn on the A/C using the app to pre-cool the car in advance. I suspect this is some type of battery conditioning at the start of every drive. After those first 3-5 miles energy consumption settles down to a reasonable value. I suspect the first leg of your 6 mile test suffered from this phenomenon.

I have 4,700 miles on my car now with a lifetime average of 257 Wh/mi. I’m quite happy with that performance.

I tried a test yesterday to see how much the A/C affected consumption. Driving on the interstate at 65 mph. I brought up the power consumption graph. 90 degrees outside. With the A/C set at 70 on auto the graph showed I was using about 255 Wh/mi. I then turned the temp down to 62 which caused the fan speed to increase significantly. The power graph barely changed (a little, but not a lot). This leads me to believe the A/C setting is not a huge contributor. I didn’t test it with the A/C turned off because turning off the A/C is not a realistic option for the real world. Hope this info is helpful.

 

[Djcmy]

So far my lifetime is kw/m is 303. Now have about 675 miles. Was yours this high when you started out and eventually go down?

 

[rxlawdude]

What is your avg speed and what us ac set on?

Average 75mph, temp set 69-72F.
When I get home I will analyze the Teslafi data.

 

[rxlawdude]

The first several miles every time I drive the car have extremely high energy consumption. Even if I turn on the A/C using the app to pre-cool the car in advance. I suspect this is some type of battery conditioning at the start of every drive. After those first 3-5 miles energy consumption settles down to a reasonable value. I suspect the first leg of your 6 mile test suffered from this phenomenon.

I have 4,700 miles on my car now with a lifetime average of 257 Wh/mi. I’m quite happy with that performance.

I tried a test yesterday to see how much the A/C affected consumption. Driving on the interstate at 65 mph. I brought up the power consumption graph. 90 degrees outside. With the A/C set at 70 on auto the graph showed I was using about 255 Wh/mi. I then turned the temp down to 62 which caused the fan speed to increase significantly. The power graph barely changed (a little, but not a lot). This leads me to believe the A/C setting is not a huge contributor. I didn’t test it with the A/C turned off because turning off the A/C is not a realistic option for the real world. Hope this info is helpful.

Remember that the cabin AC you set is independent of the energy used to cool/heat the batteries.

 

[SSedan]

Sun load can add significant load beyond temperature.

 

[mark95476]

If you really want to make your Y's range look terrible:
- Base everything on what you see as you just start driving
- Things will settle down after you drive (like your return leg) so make sure you ignore those numbers at the end of the trip and focus on what your car tells you at the start
- Only take short trips (floor it!) so numbers look terrible


Do NOT do the following test:
1) Drive your 6 mile loop with the AC on and record the power dissipation (x kWh)
2) Drive your 6 mile loop with the AC off and record the power dissipation (y kWh)
3) Compare the two which will tell you if the AC if truly killing 50% of your range (y = 2*x)


A response on a similar thread:
Range Efficiency Question

Try longer trips. Short trips aren't efficient in any vehicle.

A ridiculous example--lets say your car is parked in your drive way.
A) Turn on your car.
B) Drive 5 feet.
C) Turn off your car.
D) Turn on your car.
E) Drive back 5 feet to it's original position.
F) Turn off your car.

Repeat A to F hundreds of times and you'll have traveled very little distance and expended a lot of fuel (gas, electrons) which will give you really awful efficiency.

 

[captanzuelo]

Took 6 mile test run. 50 mph via cruise control. Ac set at 71, fan speed 6. wh 341, projected range 150. Return trip same, but ac and fan off, wh 175, peojected range 381.

Now do it the other way around. First half of the trip with A/C and fan off.

 

[asa8080]

If you really want to make your Y's range look terrible:
- Base everything on what you see as you just start driving
- Things will settle down after you drive (like your return leg) so make sure you ignore those numbers at the end of the trip and focus on what your car tells you at the start
- Only take short trips (floor it!) so numbers look terrible


Do NOT do the following test:
1) Drive your 6 mile loop with the AC on and record the power dissipation (x kWh)
2) Drive your 6 mile loop with the AC off and record the power dissipation (y kWh)
3) Compare the two which will tell you if the AC if truly killing 50% of your range (y = 2*x)


A response on a similar thread:
Range Efficiency Question

Try longer trips. Short trips aren't efficient in any vehicle.

A ridiculous example--lets say your car is parked in your drive way.
A) Turn on your car.
B) Drive 5 feet.
C) Turn off your car.
D) Turn on your car.
E) Drive back 5 feet to it's original position.
F) Turn off your car.

Repeat A to F hundreds of times and you'll have traveled very little distance and expended a lot of fuel (gas, electrons) which will give you really awful efficiency.

You missed the point. There is no need to be efficient trip. All we need to measure a delta between drive with AC and without. It’s called differential method in engineering. Momental energy consumption is all what we need