Excessively high consumption

[TheLex]

Sorry for the newb question. We have put 362 mi on the car since delivery and charged it up 151 kWh. That's a consumption of 0.42 kWh/mi or 420 Wh/mi, which seems very excessive.

This is primarily rural driving without a lot of stoplights and at speeds under 55 mph. The only caveat is it's been horribly hot, with not a day below 100° since we've gotten the car. Today it was over 110°, and it's still 91° at 9pm. Is it the extreme heat that's killing the efficiency? Based on this efficiency, I'd only get a max of 179 mi of range. Ugh.

 

[Big Earl]

Extreme heat requires a lot of energy for air conditioning, which comes from the battery pack - energy that could otherwise be used for driving. Short trips have a bigger impact than longer trips because the energy used to cool the cabin down is not amortized across very many miles - high numerator, low denominator.

Parking in shady spots can help a lot. Ceramic windows tint also makes a big improvement in occupant comfort in hot weather.

 

[RandyS]

What does your screen say the average energy consumption is in watthours per mile? And where did you get the 151 kWh number from?

 

[thesmokingman]

Is it the extreme heat that's killing the efficiency? Based on this efficiency, I'd only get a max of 179 mi of range. Ugh.

Most likely yes. Normally a LR should get around 280 Wh/mi so you're very far off that average. Just remember the car is cooling the cabin as well as the battery so something's gotta give and that's efficiency. I would wait till after the heat wave is over and then you can get more of a sense of the efficiency.

 

[bo3bdar]

Running AC seems to be fairly expensive in terms of energy. As a data point, I just ran mine for 1.5 hours while sitting in the garage listening to music and cooling off from the wicked heat wave. It's the only AC I have easily available, and it was a good experiment.

For 1.5 hours of just AC and music, I used 10% of my SR battery, or roughly 4 kwh of power. This is a 2020 model, so it does not have the more efficent heat pump.

 

[TheLex]

What does your screen say the average energy consumption is in watthours per mile? And where did you get the 151 kWh number from?

I will check the screen in the morning. I got the 151 kWh from the Tesla app on my phone. It shows how much we have charged the vehicle since our very first charge after delivery. Delivery miles were 4. We currently have 366 mi on the vehicle. It sat for over a month after our friend took delivery. So we drove it to a supercharger and charged it up when we picked it up from her. So our total consumption does not include that first charge. After the first charge (due to sitting for the month), we have charged it 3 times for a total of 151 kWh.

 

[boulder.dude]

Tesla app shows “wall power,” what came out of the wall. There are some losses between the “wall power” and the car (especially when charging at 120V). If you have Sentry on it will consume significant power as well.

Usually people talk about efficiency of the car when driving, I.e. from the in-car power graph and trip meters, not “wall power.” Mine is roughly 240 Wh/m in spring and fall, higher in winter and summer.

 

[TheLex]

Tesla app shows “wall power,” what came out of the wall. There are some losses between the “wall power” and the car (especially when charging at 120V). If you have Sentry on it will consume significant power as well.

Usually people talk about efficiency of the car when driving, I.e. from the in-car power graph and trip meters, not “wall power.” Mine is roughly 240 Wh/m in spring and fall, higher in winter and summer.

Sentry is off. I've only used superchargers so far. Should I assume about a 15% loss?

 

[Rocky_H]

We have put 362 mi on the car since delivery and charged it up 151 kWh. That's a consumption of 0.42 kWh/mi or 420 Wh/mi, which seems very excessive.

Well, no. You could have a so-called "consumption" value of infinity if you measure it that way. The car does consume some energy in its lower power idle modes while it is parked and moving 0 distance, so some energy divided by 0 is infinity Wh/mi. The assumption built into your calculation method is that the car never consumes any energy when it isn't moving, and that's not true. The consumption/efficiency ratings would be closer to the expected values if you only look at it while driving and using the car. Idle consumption while parked is going to throw those numbers off some.

 

[voxel]

Sentry is off. I've only used superchargers so far. Should I assume about a 15% loss?

Yes... but also pre-conditioning to SC eats up kWh - it's heating up the battery pack as you drive. I personally don't bother navigating to a SC on the screen unless I know I want to precondition. Efficiency goes to crapola with SC preconditioning. Yeah you charge faster... but if you are in no rush - why?

Your 151 kWh is probably - 129 kWh to the battery pack. Then if you precondition to the SC every time... that's more losses there. I noticed my 3 and Y would go from 220 Wh/mile and 280 Wh/mile to 325 Wh/mile and 420 Wh/mile when preconditioning.

 

[avs007]

Running AC seems to be fairly expensive in terms of energy. As a data point, I just ran mine for 1.5 hours while sitting in the garage listening to music and cooling off from the wicked heat wave. It's the only AC I have easily available, and it was a good experiment.

For 1.5 hours of just AC and music, I used 10% of my SR battery, or roughly 4 kwh of power. This is a 2020 model, so it does not have the more efficent heat pump.

10% for 1.5 hours seems a bit high. I use Camp Mode on mine all the time... Even in 100+ degree heat, I only use about 2-3% per hour... Granted I have a LR, so maybe that's equivalent?

 

[kingkong5]

Was the battery at 100% when it was delivered to you? Because the 151 kWh that you put back on it could be more than what you've used so far, if the battery levels are different from then to now.

 

[avs007]

Was the battery at 100% when it was delivered to you? Because the 151 kWh that you put back on it could be more than what you've used so far, if the battery levels are different from then to now.

Mine was delivered with 80% SoC or something close to that.

 

[TheLex]

Here's the latest efficiency stats from the Tesla screen itself. You can see that since we charged it yesterday, consumption has been 390 Wh/mi. Of course it was 113° yesterday. Overall efficiency since new is a bit better, at 316 Wh/mi, but that's still far higher than what I've seen from others here on the forum. Again, a friend took delivery in July, and the car sat at her house until we got back from our summer vacation in August. So the car did sit for a month. When I ran my calcs, I discounted the very first charge, since that was to refill the battery's energy loss from the car just sitting.

The overall efficiency number of 316 Wh/mi, however includes that time that the car sat for a month. However you can see from our most recent trip to pick up the kids, that the efficiency is still at a rather dismal 322 Wh/mi. Temps are a bit lower today at "only" 106° lol.

 

[TheLex]

Was the battery at 100% when it was delivered to you? Because the 151 kWh that you put back on it could be more than what you've used so far, if the battery levels are different from then to now.

Yes it was charged up to 100%. A friend took delivery for us because we have been out of the country all summer. By the time we picked up the car from our friend a month later, the car needed to be charged again. My calculations discounted that initial charge to replenish what was lost from the car just sitting.

 

[TheLex]

Yes... but also pre-conditioning to SC eats up kWh - it's heating up the battery pack as you drive. I personally don't bother navigating to a SC on the screen unless I know I want to precondition. Efficiency goes to crapola with SC preconditioning. Yeah you charge faster... but if you are in no rush - why?

Your 151 kWh is probably - 129 kWh to the battery pack. Then if you precondition to the SC every time... that's more losses there. I noticed my 3 and Y would go from 220 Wh/mile and 280 Wh/mile to 325 Wh/mile and 420 Wh/mile when preconditioning.

I have not been preconditioning. It's been extraordinarily hot (average over 100° temps) and the car has been on the road for 15 minutes before it gets to the supercharger.

 

[TheLex]

Well, no. You could have a so-called "consumption" value of infinity if you measure it that way. The car does consume some energy in its lower power idle modes while it is parked and moving 0 distance, so some energy divided by 0 is infinity Wh/mi. The assumption built into your calculation method is that the car never consumes any energy when it isn't moving, and that's not true. The consumption/efficiency ratings would be closer to the expected values if you only look at it while driving and using the car. Idle consumption while parked is going to throw those numbers off some.

Good point. See my post #14 above where I took a screenshot of the car's screen showing the efficiency ratings as of today.

 

[avs007]

What part of NorCal are you in? Your numbers look fine. When I was driving thru California last week, I was averaging > 400 whm when I got to the Williams SC... When I got to Concord, I was down to 350 whm. When I was driving between SJ and SF, I was averaging 320 whm.

 

[TheLex]

What part of NorCal are you in? Your numbers look fine. When I was driving thru California last week, I was averaging > 400 whm when I got to the Williams SC... When I got to Concord, I was down to 350 whm. When I was driving between SJ and SF, I was averaging 320 whm.

I'm in the Sierra Foothills near Folsom Lake. It's hot like the blazes here.

 

[avs007]

I'm in the Sierra Foothills near Folsom Lake. It's hot like the blazes here.

Are there a lot of hills where you are? I live on a hill as well, and it really throws my numbers off... If I reset my energy usage when I'm already at the base of our hill and I stay in the valley, I can average 265 whm for the course of the day... If I reset at the top, then drive down, I can average closer to 200 sometimes < 200 whm....If I end at the top, then depending how much driving I do, I can average anywhere from the low 300's all the way up to the 600's.