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Energy consumption P85D

Energy consumption P85D

Hi there!

This is my first post here as I’m a happy new owners of a second hand Model S P85D from 2015.

I have been using my Tesla for a month now, and I’m wondering if the energy consumption is « normal ».

From the « Trip » screen in the car, I’m consuming on average 250Wh/km. That seems a bit high to me and I just wanted to know is it’s normal after only 48K kms. As a result I can only ride 100-150 kms from 80% to 20%.

I’m not particularly driving like a maniac and I’m most of the time in the traffic jam of Melbourne.

If someone can help me understand that’d be great. Let me know if you need more info.

Thanks everyone

Darthamerica | 17. Dezember 2019

What's the weather like?

Darthamerica | 17. Dezember 2019

For stop and go and depending on how you drive, if you have 21" tires, you could see numbers like that.

vince.gross | 17. Dezember 2019

Thanks Darthamerica for your answers!

The weather is like around 25 degrees (nothing extreme) and I actually have 21" wheels with Michelin Pilot Sport 4S.

What would be a "normal/acceptable" number? Do you agree that is currently way too high?

Also, I have a dashcam installed (from the previous owner), but I don't reckon the energy consumed by it is something to consider?

Darthamerica | 17. Dezember 2019

It can be if you're doing a lot of stop and go short trips. To see the more typical 180-200Wh/km you have to drive more than 20km at a time and maintain around 100km/h. Also if you're not on level terrain that will increasing consumption as well. When you can take a longer test drive, 50km+ At 105km/h and let me know what you see.

Darthamerica | 17. Dezember 2019

Oh and don't charge beyond 90% otherwise you're regen may be limited and that will impact overall efficiency.

Darthamerica | 17. Dezember 2019

Your* regen

Darthamerica | 17. Dezember 2019

Also important is tire pressure. 42-44 PSI.

vince.gross | 18. Dezember 2019

I don't charge above 90%, I checked my tyre pressure and it's above 42psi. Looking forward to testing on a long distance to see.

Is there a way to check battery health? How can I be sure the issue is not from the battery? Maybe the previous owner did something wrong?

Darthamerica | 18. Dezember 2019

That car probably had about ~77kWh usable capacity to start. Download Stats for Tesla or Remote S and do a charge. Divide the result by 77. You're probably only 3 to 5% degraded. It should stay there for quite a while. You could also just take it to Tesla and ask for them to check it out.

vince.gross | 21. Dezember 2019

I tried the car on the highway for about 10km, and I noticed that my average was 190wh/km. I have a friend who owns the exact same car (same year, same wheels, etc.), he is also driving around the city of Melbourne with all the traffic jam and his average is 150... Something is definitely wrong here.

I asked Tesla to check the issue on the phone, they are investigating remotely and they will gt back to me soon. I'll keep you guys posted.

Thanks again for your help!

jfemd.va.us | 21. Dezember 2019

I owned a P85DL for over four years (now in a Raven Performance). My lifetime average Wh/mi in the P85DL was 315 which is about 195 Wh/km. Attaining a Wh/km of 150 (which would be about 242 Wh/mi) in a performance Model S with 21" wheels would be pretty hard to do. Your 190 Wh/km is not too far from the norm.

jordanrichard | 21. Dezember 2019

Vince.gross, first congrats on getting the car.

Second, the tire pressure recommendation here in the states is 45. Look at the sticker on the door jam. Also the number of miles, sorry kilometers on your car won’t increase the energy usage per mile/kilometer. Over the past almost 6 years, mine has gone down each year. I have 174,000 miles and my present life time usage avg is 319 per U.S. mile.

You can’t make a definitive determination of energy usage based on 10 km of driving. Also, don’t listen the Darth’s bit about the usable capacity. Meaning, those are numbers that are only going to confuse you and really has nothing to do with energy usage per kilometer.

You didn’t say how long your friend has had his car, but if he is a long time owner, with the same exactly model and wheels and tire pressure, then you can do a proper comparison. If he isn’t, Is old highly recommend talking with the local Tesla Owners Club, specifically veteran owners.

I also highly doubt despite what Darth is suggesting, which again has nothing to do with per kilometer energy usage, that you probably have up to 5% degradation with only 48,000 kms. As I said I am at 174,000 and I have 6%. As to how to check the battery’s health and assuming you mean what it’s 100 SOC range is, well, you could simply charge it to 100% and see. Do keep in mind though, don’t let the car sit for hours on end at anything above 90%. So another way to check your full range without going to 100% is to go to 90% then take the displayed kilometers and divide by .9.

Lastly, if your charging habits and usage keep the battery in a very narrow range like 70-90%, over time the algorithms that calculate your rated kilometers will get wonky. This is because it is calculating based on what it sees in that narrow 20% usage. Think of your battery like it was a rubber band. Periodically your need to “stretch” it out to see what its full potential is.

tes-s | 21. Dezember 2019

"Also the number of miles, sorry kilometers on your car won’t increase the energy usage per mile/kilometer."

Yep. I don't recall anyone posting that their efficiency has changed with the age or mileage of their car.

I often see DOUBLE the energy consumption on short trips when it is cold out. Battery and cabin heaters drawing a lot of juice during the whole trip. Then there are the usual things that drive down efficiency - driving fast, improper tire inflation, headwinds, etc.

There is a small chance it could be an issue - not with the motor or battery, but something else. For example, a brake caliper that is hanging. Rare, but it does happen particularly in corrosive (salt) environments.

My diagnosis: your car is fine. But I'm not a doctor.

jordanrichard | 21. Dezember 2019

Ya but tes-s, you have stayed at a Holiday Inn Express.......... :-)

ParklandFLMike | 21. Dezember 2019

I have owned a 2014 P85DL for 5 years now. I have 21in wheels and my lifetime avg is 360 wh/mile which converts to 223 wh/km. I have 52,000 miles on the odometer. I live in south florida and run my AC all year round and i have a short commute of 2 miles which results in less efficiency.

Your average sounds about right to me considering the AC and Heater uses a lot of energy. If you are in stop and go traffic and using the AC, this will greatly increase your ratio of wh/km simply because you are using a lot of energy and your car is not moving. Precooling the car while in a parking lot will also increase your wh/km. Driving in rain will also reduce your efficiency.

If you can find a nice highway with little elevation change on a calm wind day with no AC, you should be able to average about 176wh/km at 105km per hour.

Darthamerica | 21. Dezember 2019

@Vince you don’t have to take my word for it, just download Stats App, you’ll see for yourself what is going on.

jfemd.va.us | 21. Dezember 2019

PSI for 21" wheels is 42; 19" wheels = 45.

vlad22 | 21. Dezember 2019

My p85D late 2014 averages about 220-240 wh/km in the warmer month with the same rims and tires as OP. Winter in Alberta i typically see high 200 to low 300. I would say there is nothing wrong with your car. Ive found that to get to or below 190wh/km the weather has to be just right, no wind and cruising on a flat highway at about 50mph with and a tail wind lol.

Bighorn | 21. Dezember 2019

PSI for staggered 21s was 38F and 40R originally.

vince.gross | 22. Dezember 2019

ERRATUM: My mate made a mistake. When I asked him again based on your reactions here, he had a closer look, and he is more close to 190 on average, not 150. Sorry about this. I was repeating what he said without double-checking.

Thanks for all your responses! I'm waiting for an answer from Tesla who are currently investigating. I'll keep you all posted!

I'm not sure how to "download the stats"? to check my battery health?

p.c.mcavoy | 22. Dezember 2019

@vince.gross - “Stats” that is referenced is a third party app available for iPhones. You can buy it on the Apple App Store. That is what darth is referencing. Last I heard it’s about $20 USD to purchase. The developer of the Stats app used to post here regularly but stopped doing so a couple years ago. A few of us here actually are the ones that explained to him ways to look at battery trends over time (last I saw his degradation over time trend chart was directly taken from a graph I created and shared with him on this forum probably 2.5 years ago).

Anything the Stats or other apps show you for battery capacity is just being calculated from the displayed rated miles and % SOC (state of charge) numbers displayed in the car. All of these apps work by pulling information available via the API. Anyone that has researched the details of the API spec will tell you that there is no values for actual battery capacity or percent degradation provided.

vince.gross | 09. Januar 2020

Hi Everyone!

After an investigation from Tesla, it turns out that everything is normal with my car!

The issue is the fact that I'm making mainly short trips (average ~13km), so the battery doesn't have enough time to warm up, and the energy consumption is up the sky.

I'll have to do some tests and schedule a charge just before I'm using the car (so the battery will be warm already) and I'll monitor the energy consumption closely and see if any difference.

To be honest, if I knew that before buying the car, I'd have taken the long-range one... I'm a bit disappointed here...

Please let me know if you think this explanation isn't right (if you make only short trips as well, with a better range than me on a similar model). On average I'm doing only 150km from 90% to 10% with an average of 250wh/km.

I'll keep you guys posted, thanks for your help!

Darthamerica | 09. Januar 2020

@Vince it seems just as I suspected... The short trips. This is why I recommended a 50km trip so that the battery warms up and your consumption averages out.

revrev4ruach | 09. Januar 2020

Thanks, Vince. Keep us posted.