I charge daily Monday through Friday to 90%. On Friday I left work with battery showing 278 miles @ 90%. 90% of 75kWh is 67.5 kWh. I drove around quite a bit all weekend and arrived at work today Monday with battery showing 30 miles left. My trip meter shows that I have driven 201.3 miles @ 248 Wh/mi 50kWh total since last charge. If the battery pack is around 75kWh minus the consumed 201 miles @ 50kWh, minus 7.5 kWh from charging to 90% instead of 100%. Shouldn’t I have around 17.5 kWh & 70 miles left instead of 30 based on the 248Wh/mi I’ve been averaging. I understand there’s some phantom drain which is normally 2-3 miles overnight but here I’m missing 40 miles over 3 days of driving.
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Help me understand battery consumption
- Thread starter Redrick00
- Start date
The manual doesn’t go into much detail about how that 248 number is generated. It is possible that it is strictly drivetrain efficiency, and doesn’t account for other drain like cabin heat/conditioning, headlights, computer/camera/screen, idle vampire power etc....
Spread over three days that doesn’t seem too bad.
Spread over three days that doesn’t seem too bad.
There is some battery reserved that we dont get access to... just like an ICE car that has a gas tank thats 17 gallons, and you drive it till its "empty" (either on E or showing dashed lines for range left) and fill it and it only takes 15.9 or 16 gallons.
I've never had that be the case on an ICE. If they say the tank is 17 gallons and you run out of gas, you're putting 17 gallons in, or damn close to it. Now yes, sometimes the gauge goes to E prior to it being empty, but that doesn't mean you don't have usage of the fuel capacity that is present if you run it dry. Where the other 25kWh went is a perfectly valid question. The "fudged range" as I understand it is above and beyond what is supposed to be a usable 75kWh.
Polly Wog
Member
There are a lot of posts on this subject within the TMC forum, covering all of Tesla's vehicles, and not a lot of folks know the formula that Tesla uses. We do know a few things though: 1) The rated range is based upon "usable" capacity, not total battery capacity; 2) The wh/mi calculation does not include energy used when the car is sleeping, idling, warming up, etc.; 3) The wh/mi calculation DOES INCLUDE the HVAC and battery conditioning energy while the car is moving (in drive or reverse, at least).
There is some battery reserved that we dont get access to... just like an ICE car that has a gas tank thats 17 gallons, and you drive it till its empty and fill it and it only takes 15.9 or 16 gallons.
If
Never happened for me, in 39 years of driving, and I have driven my ICE cars many (MANY) times down to where the dashed lines show on mileage left, or the dial was UNDER the "E".
I actually ran out of gas about 300 feet from a gas station this time last year in my 435, saying "I can make it, I can make it", and had to push the car into the gas station with help from my son, who I called to help me, and when I filled it up I still did not get the rated gas tank capacity. It was roughtly 1/2 a gallon under.
So back to the OP's question here...
First, while using 75kWh as a battery capacity may get in the ballpark, it looks more like it is 73-74kWh to get 310 miles. Others have determined about 236-238Wh/mi for parity which is 73.1-73.7kWh...anyway...daily vampire losses seem to be 1-2% per day, probably closer to 1%, so that is ~9.3 miles of loss there. If you do ANY kind of pre-heating then that could definately account for the rest of the losses...Even if you aren't preheating, and now I could be wrong but I will say this because it is likely...as soon as you get in your car if you have the HVAC system on before, it will automatically turn on so I THINK any of that usage BEFORE you step on the brake won't be counted in your Wh/mile. Also looking at your car with the app will increase the "vampire" losses.
First, while using 75kWh as a battery capacity may get in the ballpark, it looks more like it is 73-74kWh to get 310 miles. Others have determined about 236-238Wh/mi for parity which is 73.1-73.7kWh...anyway...daily vampire losses seem to be 1-2% per day, probably closer to 1%, so that is ~9.3 miles of loss there. If you do ANY kind of pre-heating then that could definately account for the rest of the losses...Even if you aren't preheating, and now I could be wrong but I will say this because it is likely...as soon as you get in your car if you have the HVAC system on before, it will automatically turn on so I THINK any of that usage BEFORE you step on the brake won't be counted in your Wh/mile. Also looking at your car with the app will increase the "vampire" losses.
The thing is, I have only been on these specific boards for about 3 weeks or so, but am not new to car forums by any means. On these boards the "wtf is wrong with my mileage????" is obviously a hot button. Its definitely top five in post topics. I get it, I really do. I am also a new owner of an EV. For a lot of model 3 owners, this is there first EV so they (and I) are understandably sensitive about every little thing.
This is no different than people asking / talking / complaining about why their ICE engined car does not get its stated mileage. Even coming from "luxury" (using that term loosely) manufacturers like BMW, whose cars I have driven for the past 12-15 years as new leases every 3 years, every week to 10 days, someone would come on the forum and say:
"Is there something wrong with my car??? I am not getting XX mileage, and I am using the right gas, and driving gingerly" etc etc etc.
For ICE cars, people are used to the fact that they would not get the stated EPA mileage unless they baby the car, and even then its difficult. BMWs also have an estimated range till empty, and (like the tesla) it changes as you drive.
People worry about their top end max range, but likely are not driving it very often, if at all. I do to, I am 100% guilty of this. With that being said, trying to figure out where the X or XX miles went, running calculation numbers etc. There is a term called "analysis paralysis". Data is good, sometimes too much data is bad, if a person does not have the appropriate way of evaluating that data.
My original post was just to say "ICE cars do this too" which they do. I stand by the fact that, if one actually looks at the gas tank capacity in the spec sheets for their ICE car, and then gets and looks at their receipt when they fill up at the gas tank (as I have, keeping receipts for my diesel powered car in case there was a problem at fill up), they would see that even on "E" they are at least a gallon short of the capacity.
I have read enough here to read that teslas also have a minimum and maximum "reserved" area of the battery, AND that the stated range is given to us by a computer algorithm that seems to calculate range based on "stuff".
I get that people (again, including me) are hyper sensitive to it, because as I said its new. We can look to our roadster, Model S and Model X "senpai's" who, if we read, all tell us they went through this, and all came to the conclusion that range isnt an issue, just drive and enjoy it".
So, shoutout to the Model S and X Senpai's, from your Model 3 kouhai's. Thanks for helping us get through this, and thanks for repeating "its going to be ok" to all of us nervous, anxious, excited model 3 owners.
This is no different than people asking / talking / complaining about why their ICE engined car does not get its stated mileage. Even coming from "luxury" (using that term loosely) manufacturers like BMW, whose cars I have driven for the past 12-15 years as new leases every 3 years, every week to 10 days, someone would come on the forum and say:
"Is there something wrong with my car??? I am not getting XX mileage, and I am using the right gas, and driving gingerly" etc etc etc.
For ICE cars, people are used to the fact that they would not get the stated EPA mileage unless they baby the car, and even then its difficult. BMWs also have an estimated range till empty, and (like the tesla) it changes as you drive.
People worry about their top end max range, but likely are not driving it very often, if at all. I do to, I am 100% guilty of this. With that being said, trying to figure out where the X or XX miles went, running calculation numbers etc. There is a term called "analysis paralysis". Data is good, sometimes too much data is bad, if a person does not have the appropriate way of evaluating that data.
My original post was just to say "ICE cars do this too" which they do. I stand by the fact that, if one actually looks at the gas tank capacity in the spec sheets for their ICE car, and then gets and looks at their receipt when they fill up at the gas tank (as I have, keeping receipts for my diesel powered car in case there was a problem at fill up), they would see that even on "E" they are at least a gallon short of the capacity.
I have read enough here to read that teslas also have a minimum and maximum "reserved" area of the battery, AND that the stated range is given to us by a computer algorithm that seems to calculate range based on "stuff".
I get that people (again, including me) are hyper sensitive to it, because as I said its new. We can look to our roadster, Model S and Model X "senpai's" who, if we read, all tell us they went through this, and all came to the conclusion that range isnt an issue, just drive and enjoy it".
So, shoutout to the Model S and X Senpai's, from your Model 3 kouhai's. Thanks for helping us get through this, and thanks for repeating "its going to be ok" to all of us nervous, anxious, excited model 3 owners.
I don’t agree on your second point because yesterday after charging I drove for 19 miles for a total time of 45 minutes. There was a lot of time stopped idling at red lights. My trip meter since last charge showed 19 miles 4kWh @ 209 Wh/mi. My trip meter since time I started driving also shows 19miles 45 minutes at the same 209 Wh/mi which tells me the calculation included the time spent idling.
The problem is that on ICE vehicles you know the total capacity and you have an idea of the reserve amount. My wife’s KIA has a 17.4 Gal tank and if I run it to E I add close to 14 Gallons to refill, so I know there’s close to 3 1/2 on reserve. I’ve driven my wife’s KIA for 30 miles under E with no problem.
Sorry, just want to nit-pick for a sec. E does not mean Empty. Engine shutting off due to no more gas is EMPTY. Then and only then can you start to compare how much gas it takes to fill the tank vs spec capacity.
If you read my post you would see that I indeed ran my BMW empty as in ran out of gas on the street, and it still did not take the stated capacity of the tank. In any case, the Tesla's "empty" is no different than E on a ICE cars gas tank.
EDIT:.. hmm I thought I said that somewhere but dont see it. In any case, yes I have run my ICE BMW down to empty as in stalled on the street, about 300 yards from a gas station. I needed to call my son and have him help me push the rest of the way.
Even in that situation it did not take the stated capacity. In fact, it was almost 3/4 of a gallon short of the full stated capacity of the tank according to the manual, and indeed was "empty" as you say.
Someone would also need to calculate their range in the tesla by running it till it stopped as well, since "0 miles" would not be "empty".
It has been my experience in driving my 85 that, the mileage I get depends on how I drive, what the temperature outside is and if things like Ac and or heat is being used. If I accelerated quickly then I burn mileage. So 1 mile takes more energy and consequently I lose mileage. I just don't worry about mileage and how much I should get anymore. I drive for fun, so if 1 mile takes more energy and I have to charge more....it doesn't matter. WAY cheaper than gas!!
Yeah I did read your post. So that gas pump automatically shut off EXACTLY when the tank was full? How do you know this?
AlanSubie4Life
Efficiency Obsessed Member
Just want to say...this is not true. The rated range has nothing to do with "stuff". It is the capacity of the battery (whatever it decides that is, but for a "new" battery it appears to be about 75kWh (there is debate on this number, but it's close to this) divided by a constant which is about 242Wh/mi (so 75kWh/242Wh/mi = 310miles). These are somewhat approximate numbers, but the point is that the rated range is not given by an algorithm (with respect to driving style) and does not change unless battery capacity is determined to be lower or higher for some reason (VERY cold temperatures, age, etc. yes that's an algorithm but a little different than what was implied).
I think he meant in park, before you start driving, when he said "idling". The key point is that that "since last charge" data does not include losses when you're not in the car (which to some extent you already knew - but it's more than just the vampire/phantom losses, depending on exactly how you used the car). It probably doesn't include losses when you get into the car, before you put it in drive, either. When it "stops" and "starts" counting EXACTLY, I don't know. Anyway I think that's likely the reason for your 10kWh discrepancy, can you think of situations where you might have been sitting in park for any period of time? It's definitely high for 3 days of vampire drain but that could also happen under certain scenarios where the car decides not to sleep.
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Lol...
Im not sure what your point is. I will explain my point again in case its not clear what I am saying. I am saying that the tesla reserves a part of the battery just like an ICE car, so trying to calculate usage because one has a 75kW battery and wondering where the "extra" miles went is futile.
Just like an ICE car, you CANT run it all the way empty, because when its empty its still not empty. When you run out of gas (as in stopped the street), there is still gas in the tank but you cant USE it so its "empty". When you fill the tank till the gas gauge stops its "full" as full as you can get it but there is a reserve there, so one can never completely fill or empty an ICE engine, and the tesla is the same.
What point are you trying to make thats different from what I am saying?
The bolded part doesnt = "stuff"? Its an "approximate number divided by a constant, that changes when the battery capacity is determined to be lower or higher" per what you stated (and I dont disagree with at all), but how does that make me saying "stuff" not true?
EDIT: In any case, I have derailed this particular "battery consumption" thread enough.
AlanSubie4Life
Efficiency Obsessed Member
I just edited my post (as you posted) to make that more clear. I understand what you're saying, but the fact is for the OP's question, this is not the reason for his loss. It just isn't. This rated range number simply does NOT change over the course of a few days - unless there is a software bug (there was a while back but that has been resolved a couple months ago). He's in Los Angeles. Rated range has nothing to do with driving style, vampire losses, temperature (below 10F or above 100F, maybe), RWD/AWD/P3D, etc.
Correct, in an ICE car when you run out of gas you haven't run out of gas, but how do you know there is still gas in the tank vs just in the lines going from the tank to the engine? Where is the fuel line connected to the tank specifically in any particular car.
Trying to calculate anything on the Model based on a 75kWh battery is futile because no one knows any official number for the capacity except Tesla since they haven't released that information.
I'm not saying that NO car has a "reserve" but where that reserve is in relation to the specified tank capacity is not cut and dry.
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