Forums

Watts per mile?

Watts per mile?

I have a Tesla long range model, up to 325 miles. I am new to owning a Tesla. I noticed yesterday I drove about 70 miles but the car showed closer to 100 miles driven based on the battery. Today, I set range mode to "on" and did some tests. Driving about 17 miles, the car showed that I had driven 20 miles (based on the green battery meter). My average watts per mile was about 350-380 driving around town and a local two lane highway / road.

Now for my question, realistically, if I "fill" the car to 300 miles, driving normally in comfort mode, how many miles will I really be able to drive both with range mode on and with range mode off. This is especially important for long trip planning, for instance, from Monterey to San Francisco and back.

I also want to verify that what I am seeing is "normal". Any insight would be appreciated, thank you.

Sandman89 | 27 juli 2019

I have Tesla Model X 2016 for last 2 plus years.Mine show 258 miles full charge but it did not go 258 miles.You have to remember it depends on your driving habit,outside Temperature, load in the car, use of AC or heating etc.325 mileage is for ideal conditions but conditions are never ideal so with your fully charged battery in normal conditions you can drive safely for about 280-290 miles leaving about 30-40 miles for energy wastage.Again this is just rough estimate.While your are driving your car will tell you how much mileage you will get and if your destination is not in the mileage range than it will tell you to stop at supercharging stations and get it charged.

aatisha | 27 juli 2019

I got my MX on July 9. Since then, I've been getting a little more than half the range the car says. For example, when I charge it to 250 miles, I get about 150 miles. Put another way, the car range decreases roughly 1.75 miles for every real world 1 mile driven. Granted its been hot here in Michigan since I received the car. It's really the only disappointing thing about the MX so far, but a pretty major one.

Sandman89 | 27 juli 2019

100 miles less than what it charged is not what my experience is.For 250 miles charge on my MX i can easily drive 200 miles without any problem.

selbstsa | 27 juli 2019

Yeah it is interesting. Rough math is under perfect conditions a 100,000 watt, 1 KW, Tesla X would average about 308 watts per hour to attain the full 325 miles (100,000/325). If the actual performance is 370 there is about a 17% reduction in real world performance which means the real word capacity on a maximum charge is about 280 miles. This is good and important to know since on a long trip, therefore I would plan to stop every 230-250 miles for a supercharge to be sure I do not come close to the limits. I think it i important for newbees
like me to know there is a 17%-20% overhead tax per mile and plan accordingly.

I am curious to know if any of you have measured the increased mileage from using extended range mode.

ratchet | 27 juli 2019

Short distance driving will be worse than long trips. It takes a lot of energy to get a heavy vehicle like the MX moving. My 2017 100D needs to average 330 Wh/mi to achieve the rated distance. However, my daily commute is 4 miles with a few traffic lights so I usually get 350-380 Wh/mi. I also have a destination where I go on the weekends that is 6 miles away. Driving there I get about 340 Wh/mi but the return trip is 290 Wh/mi. Point being that you need to account for temperature (internal cabin A/C or heat as well as battery heating/cooling), hills, wind, driving speed (faster speeds increase power consumption per mile), driving habits (quick acceleration can be fun but burns more energy per mile), and other factors. Range mode limits acceleration and the amount of heating/cooling can be used so you can get closer to rated distance but it does not guarantee that you will get that much distance.

TeslaTap.com | 29 juli 2019

Remember the range is based on EPA ratings, or another way to look at range is based on traveling at a constant 65 mph on flat land at 70 degrees outside, and using standard tires in good condition (i..e 20" tires, not 22"). Change any of these and range will go down. For example, traveling at 80 mph is far less efficient (in any car - EV or ICE) than traveling at 65 mph. Traveling at 40 degrees outside mean the heater will be on, reducing range. Having fun with hard accelerations and braking will also consume far more power.

johnse | 29 juli 2019

I've put 22,000 miles on my X in 16 months. You will definitely get different ranges based on how far you drive, the exterior temperature, how much you use climate control (fans and heaters use the most, AC uses less than heating, seat heaters use much less than cabin heating.) In cold weather, it will turn on heaters to heat the battery to its preferred temperature for regenerative braking (charging).

The range displayed is computed based on a rated (fixed) average. On mine that is 330 Wh/mile. I never bother to display that rated range and just show charge percentage instead. Around town (Seattle suburbs) my average is right around the rated when I look at the "since last charge" computations shown on the "Trips" card. During the winter that went up to around 380 Wh/mile.

I've done numerous long drives, down to California and Arizona. The trip computer estimates have been very accurate--even a bit pessimistic (as in I arrived with more charge than it expected at the beginning.)

The range used by the trip computer when deciding on Superchargers takes into account your actual driving history along with temperature and elevation changes. It also gives you a realtime estimate on what your charge state will be when arriving at your destination. If your driving is using more energy than expected (going much faster, heavier load, bad weather--whatever) that number will start dropping. If using less, it will edge up.

So in general, don't worry too much about it. On long trips, just put in a destination, drive, and charge where it tells you :)

GranpaJohn | 30 juli 2019

MX100D, 21K miles since Dec 8, 2018
Using the TEZLABAPP.com Phone App and On-Screen browser I can track every trip:
Highest Min Miles Drive Charge Superchargers Software Efficiency Temp
Charge Charge Driven Count Count Visited
293 mi 36 mi 6123 mi 248 94 5 2019.24.4 73fb1ab 90.1% 76F

This shows June 1 to July 30 overview. 90% efficiency is over all speed ranges

artc1688 | 30 juli 2019

as a new MX owner, I did not realize (nor informed by Tesla Salesperson) that a 22" RIM would cost me 10-15% decrease in range!!! not to mention the $5500(?) i had to pay for these Onyx Rims

Given no-one mentioned about the potential impact of the 22" RIM, this could be a potential factor into t less desirable range

gtimbers | 1 augusti 2019

I have a Model X 100D from March 2019, just before the refresh. Mine is rated at 295 miles. When set to range mode, EPA numbers suggest that 310 w/m will give rated range. I have tested this and you will get about your rated range if you keep consumption around 310 - 312 w/m. This is essentially impossible in real world highway driving. I can do 335 or so If I hypermile and limit my top speed to 70 mph. A/C is on.

mbirnie51 | 1 augusti 2019

My MX 75D is a March 2017 build, running v 2019.24.4 with 38,400 miles: There are 2 concepts at play here, first is capacity of the battery pack; the second is the range you can get from that battery pack.

You must understand that as your vehicle ages and gets more mileage on it, the CAPACITY of the battery pack will degrade slightly or dramatically depending on how you drain the battery and recharge it. A slight degradation occurs if you keep your discharge to above 15% and your recharge to 90% as suggested by the owners manual. A more dramatic degradation will occur if you constantly run your battery down to 0% and continually recharge to 100%. Keeping within Teslas suggestion, over time it has been shown that a Tesla with over 100,000 miles will have a reduction of the capacity of about 1.5 to 2%. So my 75KW pack would have a 100% charge of about 73.5 KW at 100,000 miles.

On to RANGE. New my vehicle would recharge to 236 miles at 100%. Now my lifetime watt hours/mile is at 346 and I can get 210 miles of range at 100% recharge. Wow, I "lost" 26 miles of range. That figure is what the battery icon on the dash shows. It is calculated by some algorithm, but can be done by hand calculation as follows. By design, Tesla will only allow you to use 72.5KW of a 100% charged 75 KW battery pack, they sequester about 2.5 KW to keep systems working and prevent bricking of the pack. So, if you divide 72,500watts by 346 watt hours/mile you get 209.5 miles of range. My asumption is that my capacity has degraded from 75 KW to about 74.5 KW at this time.

Now, if I go on a trip and keep in mind what @ Tesla_Tap and @ johnse say and some how reduce by consumption rate to 310 wh/m, I will go further than 210 miles (233 miles). The battery icon still goes down mile per mile based on lifetime rate of 346, but I can go farther cause I still have some capacity left in my pack.

Consider I recharge to 90%, so my capacity is 67KW upon start of a trip leg. I'll get to a Super Charger with 15 miles of range and have consumed 56KW of energy. That means I actualy have 11 KW left in my pack and 8.5 KW available to use. Even at 346 wh/m I should be able to travel another 25 miles.

So I don't fret over my loss of range on my icon, I know that by better driving habits, I can go over 240 miles on my battery pack. The biggest worry one should have is degradation of battery pack CAPACITY. Keep within Tesla's suggested discharge/recharge rates and your vehicle will give you 3 to 400,000 miles no problem.

ckilaru | 9 augusti 2019

I had my X for about 2 weeks now. For regular weekly commute I charge it to 80% and then let it run down to 20%. In the most recent charge, I'm averaging 370Wh/Mi and I observed a total phantom drain of about 12KWh. I'm getting about 170 to 185 miles. On the other hand I recently went on a 100M freeway trip (50M round trip) and I averaged 270Wh/Mi. My guess is, if you are going on long road trip you can get 325 or even more miles on a 100KW battery. But when you charge the car and use it for regular commute over multiple days, you won't get the best mileage as there will be some phantom drain.