Model 3 Battery Capacity

[SomeJoe7777]

The post points to the available battery capacity being different in different Model 3 models based on the Rated Efficiency and Rated Range for the Model 3.

No it doesn't. What you are calculating has no relationship to reality because the numbers you're starting with (rated range and rated efficiency) also have nothing to do with reality. Tesla's 310 mile rated range is an arbitrary number. It's useless for calculations to find the real available battery size.

The only number that is physically fixed and real is the available battery capacity in kWh. That number is around 73 kWh. All calculations have to start from this number to have any bearing on reality.

With 73 kWh of energy available in every LR Model 3, the range you can get out of the car will directly depend on what efficiency you can muster with your driving. The more efficiently you drive, the farther you will be able to go.

With 73 kWh of energy available, if you can drive efficiently enough to average 235 Wh/mile, you can drive the car 310 miles. That holds true for EVERY model 3 with the long range battery, regardless of any other configuration. Drive such that you get that efficiency, and you can achieve the "rated" range of 310 miles.

The problem is that it's a bit harder to average 235 Wh/mile in an AWD Model 3 than it is in a RWD Model 3. And it's a LOT harder to do it in a Performance Model 3. Whereas in a RWD Model 3, it's not too hard to actually do better than 235 Wh/mile, and therefore achieve better than rated range.

The EPA calculations are marred by measurements of wall power instead of battery energy, and are then fudged/derated by Tesla. They're useless as far as calculations. The rated efficiency line on the Energy Graph is not particularly useful either. It had little bearing on reality in the Model S when I had mine. In my 85D, I could achieve the rated range of 270 miles driving with an efficiency of 287 Wh/mile. That was hard to do in the Model S, but possible in the dual-motor versions. It was nearly impossible in the RWD cars. However, the "rated" line usually corresponded with a value of 305 Wh/mile or so, and therefore didn't indicate what you needed to achieve with efficiency in order to make rated range.

So in summary, the rated range and rated efficiency numbers are kind of meaningless. Any conclusions you derive from those numbers are also kind of meaningless.

 

[NewTMSMan]

I haven't looked at the at the new Energy Graph for the Model 3, but from the pictures I'm not seeing a rated efficiency number, only an average which is from the last few miles of driving. There is a constant used for rated miles, different for each car. I'm not sure you are using the right numbers.

The Model 3 RWD rated range was reduced voluntarily by Tesla so that the AWD cars, which are less efficient, would have roughly the same rated range. Given the the battery is the same for all, the RWD is more efficient, and Tesla claims all version have 310 miles rated range, yes, the calculated battery sizes would be larger for AWD than RWD. In reality, the RWD will be able to travel farther than the AWD, maybe even by the 6% you calculated.

TL;DR, the 310 mile range is an inaccurate made-up number that should not be used to calculate battery size.

The Energy Monitor Graph shows a line for the Rated Efficiency, that I then used detailed measurements to assess the value. A friend actually drove her Performance Model 3 easy enough to match the line on the screen (actually hit just below the Rated line) and verified that my measurements gave the same result. I used the same method for the RWD chart another friend provided. This clearly shows the Rated Efficiencies shown in the charts is different. Would be great if any RWD, AWD or Performance owners could validate what the Rated Efficiency in their cars show in V9.

Once you know the Rated Range for all Model 3s is 310 miles and there are difference in Rated Efficiencies, then there has to be a difference in the Rated, or Available battery capacity, otherwise the math simply doesn't work. Does not mean the packs are physically different, but may mean the available energy is limited in the RWD to put the Rated Range on par with the Performance and AWD cars.

My question would be how do you explain the reports of RWD owners getting 350-375 actual driven miles on their odometer?

How about you and your AWD buddy just start driving and see who runs out of juice first?

Pretty easy to get 375 miles even if the battery available capacity is 6% less in the RWD.

Miles = 375
Available Battery Capacity = 73.5 kWHr (my number from above)
WHr/mile = 73500 / 375 = 196 WHr/mile

As we know the hypermilers got in to the low 100s (110 according to the article) it is possible to get to 196 WHr/mile if you travel below 55 MPH, the EPA Dyno Test even showed much lower potentially as well.

 

[SomeJoe7777]

If you want to actually find the real numbers that the car is using to calculate rated range, there is only one way to do it.

• Charge to 100%, note the starting battery range number in miles, call this Rs.
• Take a long, constant, steady drive with as constant a power utilization as you can muster -- no stops, no speeding up & slowing down, no change in HVAC during the trip.
• Drive until you're down to about 2% battery, note the end battery range number in miles, call this Re.
• Find the average efficiency in Wh/mi since last charge from the trip meter, call this E.
• Find the actual number of miles you've driven since the last charge from the trip meter, call this D.

Rated efficiency in Wh/mile = (E * D) / (Rs - Re)
Actual usable/available battery capacity in kWh = (310 * Rated Efficiency) / 1000

I guarantee that this calculation will result in the same battery capacity and same rated efficiency for every LR Model 3.

 

[brianmeow]

while we are on the battery topic, i need help understanding why my driving distance dropped from 247 miles to 239 miles in the past 4 days (around 2 miles a day) while i set the charging cap at 80%. I live in SoCal and night time temp had dropped to low 60s in the last few days. I have a LR non-AWD model 3 and my avg wh/hr is around 220. Thanks.

 

[NewTMSMan]

No it doesn't. What you are calculating has no relationship to reality because the numbers you're starting with (rated range and rated efficiency) also have nothing to do with reality. Tesla's 310 mile rated range is an arbitrary number. It's useless for calculations to find the real available battery size.

The only number that is physically fixed and real is the available battery capacity in kWh. That number is around 73 kWh. All calculations have to start from this number to have any bearing on reality.

With 73 kWh of energy available in every LR Model 3, the range you can get out of the car will directly depend on what efficiency you can muster with your driving. The more efficiently you drive, the farther you will be able to go.

With 73 kWh of energy available, if you can drive efficiently enough to average 235 Wh/mile, you can drive the car 310 miles. That holds true for EVERY model 3 with the long range battery, regardless of any other configuration. Drive such that you get that efficiency, and you can achieve the "rated" range of 310 miles.

The problem is that it's a bit harder to average 235 Wh/mile in an AWD Model 3 than it is in a RWD Model 3. And it's a LOT harder to do it in a Performance Model 3. Whereas in a RWD Model 3, it's not too hard to actually do better than 235 Wh/mile, and therefore achieve better than rated range.

The EPA calculations are marred by measurements of wall power instead of battery energy, and are then fudged/derated by Tesla. They're useless as far as calculations. The rated efficiency line on the Energy Graph is not particularly useful either. It had little bearing on reality in the Model S when I had mine. In my 85D, I could achieve the rated range of 270 miles driving with an efficiency of 287 Wh/mile. That was hard to do in the Model S, but possible in the dual-motor versions. It was nearly impossible in the RWD cars. However, the "rated" line usually corresponded with a value of 305 Wh/mile or so, and therefore didn't indicate what you needed to achieve with efficiency in order to make rated range.

So in summary, the rated range and rated efficiency numbers are kind of meaningless. Any conclusions you derive from those numbers are also kind of meaningless.

Sorry but you have it backward. Show me anywhere that you can prove what battery capacity is available for use in the car? You won't find anything, the best you can show is from the tear down of one car with the actual battery capacity available. As we already know Tesla has a history of handicapping the battery capacity in their cars, the number of cells available tells you nothing.

Only way to show the difference is based on the Rated numbers. Which Rated number that I used was wrong? The Rated miles of 310 mile, or the Rated Efficiency that I took from Tesla's Energy Monitor chart?

What you can achieve in any given car with any given battery is meaningless actually without some independent measurement of the energy use per mile. Anything based on utilization that you read from the car itself can easily be manipulated with Miles being the only independent variable you can actually validate. Where exactly are you getting your independent reading for the Efficiency? I can choose any battery size and back calculate the required WHr/mile to meet the 310 mile range, which is exactly why I used Rated, as this is independent of any measurement and has to be internally consistent.

 

[SomeJoe7777]

Sorry but you have it backward. Show me anywhere that you can prove what battery capacity is available for use in the car?

See my second post above for how to compute the actual available battery capacity.

Which Rated number that I used was wrong? The Rated miles of 310 mile, or the Rated Efficiency that I took from Tesla's Energy Monitor chart?

The numbers aren't "wrong", but they have no relation to the battery size because Tesla picked them out of thin air. They arbitrarily decided to claim the rated range as 310 miles. That's a number that has nothing to do with the battery.

What you can achieve in any given car with any given battery is meaningless actually without some independent measurement of the energy use per mile. Anything based on utilization that you read from the car itself can easily be manipulated with Miles being the only independent variable you can actually validate. Where exactly are you getting your independent reading for the Efficiency?

This is a valid point, but I have no reason to doubt the efficiency shown on the trip meter. It appears to be an actual calculation of what the car believes it is using.

And therein lies my point. The end result of all of this is -- what do I have to do to drive this car some number of miles? What indicator can I use to assure myself that I can achieve the range I need to achieve? If the efficiency indicator in the car is actually inaccurate, that's OK as long as it's consistent. I can still use it as the indicator to help me achieve some target range because the car uses this value throughout its display and calculations.

Let's say I want to drive the car exactly 310 miles. To do this, I need to keep the efficiency number below some value. What value is that? The calculation I posted above will tell us. The number may be off, but that doesn't matter because the method will work.

If we want to cross-check the computed battery capacity against real-world items that we can measure, then we can measure how many kWh it takes to fully charge the battery, and then put in an AC->DC efficiency conversion factor to estimate how many kWh we put into the battery. This can get us a good confirmation that the computed number is at least close to being accurate.


The main point here is that your assertion that the availale/usable battery capacities may be different or somehow software-limited between the LR/AWD/P models is not based on factual real-world data. The method you are using is starting with flawed arbitrary data and cannot arrive at a correct conclusion.

 

[NewTMSMan]

If you want to actually find the real numbers that the car is using to calculate rated range, there is only one way to do it.

• Charge to 100%, note the starting battery range number in miles, call this Rs.
• Take a long, constant, steady drive with as constant a power utilization as you can muster -- no stops, no speeding up & slowing down, no change in HVAC during the trip.
• Drive until you're down to about 2% battery, note the end battery range number in miles, call this Re.
• Find the average efficiency in Wh/mi since last charge from the trip meter, call this E.
• Find the actual number of miles you've driven since the last charge from the trip meter, call this D.

Rated efficiency in Wh/mile = (E * D) / (Rs - Re)
Actual usable/available battery capacity in kWh = (310 * Rated Efficiency) / 1000

I guarantee that this calculation will result in the same battery capacity and same rated efficiency for every LR Model 3.

So then you are saying that the RWD and Performance Model will arrive at the same Rated Efficiency, using that test? If you are not and the Rated Miles are the same, how do you not arrive at different Available Battery Capacity between the 2 cars?

Actual usable/available battery capacity in kWh = (310 * Rated Efficiency) / 1000

If the Performance and the RWD do not have the same Rated Efficiency (which I showed they do not at least according to the Energy Monitor) then the Actual usable/availble battery capacity has to be different. Show me anyway this is not true using the formula you provided, there is only 1 variable.

 

[SomeJoe7777]

So then you are saying that the RWD and Performance Model will arrive at the same Rated Efficiency, using that test?

Yes, exactly. They will arrive at the same rated efficiency. This is because they have the same rated range, and the same battery.

The energy monitor is incorrect as far as rated efficiency, plain and simple. It was also wrong in my Model S, so this is no surprise.

 

[NewTMSMan]

Yes, exactly. They will arrive at the same rated efficiency. This is because they have the same rated range, and the same battery.

The energy monitor is incorrect as far as rated efficiency, plain and simple. It was also wrong in my Model S, so this is no surprise.

Yes! Agreed! So either the Rated Efficiency in the Performance or the RWD car shown in the Energy Monitor is wrong (which is possible as I mentioned in my earlier posts) or if they are different the only option is the available battery capacity is different.

I would agree that charging from a low level of 2 comparable cars would provide the information needed to validate which is correct (do not agree relying on in car measurements would help as they can be adjusted). I have a HPWC and a Performance Model 3 and can independently measure the charge I put to the cars using an Aeotec power meter. What car do you have and can you measure a comparable charge?

EDIT: Meant to add I already checked this in both my Model S P100D and my Model X 100D and both are internally consistent and correct with respect to stated battery size and Rated Range using the Energy Monitor Rated Efficiency.

 

[SomeJoe7777]

What car do you have and can you measure a comparable charge?

I have both a RWD Model 3 and a Performance+ Model 3. I have a TED (The Energy Detective) unit that can measure kWh at the circuit breaker panel.

 

[TJKR]

No it doesn't. What you are calculating has no relationship to reality because the numbers you're starting with (rated range and rated efficiency) also have nothing to do with reality. Tesla's 310 mile rated range is an arbitrary number. It's useless for calculations to find the real available battery size.

The only number that is physically fixed and real is the available battery capacity in kWh. That number is around 73 kWh. All calculations have to start from this number to have any bearing on reality.

With 73 kWh of energy available in every LR Model 3, the range you can get out of the car will directly depend on what efficiency you can muster with your driving. The more efficiently you drive, the farther you will be able to go.

With 73 kWh of energy available, if you can drive efficiently enough to average 235 Wh/mile, you can drive the car 310 miles. That holds true for EVERY model 3 with the long range battery, regardless of any other configuration. Drive such that you get that efficiency, and you can achieve the "rated" range of 310 miles.

The problem is that it's a bit harder to average 235 Wh/mile in an AWD Model 3 than it is in a RWD Model 3. And it's a LOT harder to do it in a Performance Model 3. Whereas in a RWD Model 3, it's not too hard to actually do better than 235 Wh/mile, and therefore achieve better than rated range.

The EPA calculations are marred by measurements of wall power instead of battery energy, and are then fudged/derated by Tesla. They're useless as far as calculations. The rated efficiency line on the Energy Graph is not particularly useful either. It had little bearing on reality in the Model S when I had mine. In my 85D, I could achieve the rated range of 270 miles driving with an efficiency of 287 Wh/mile. That was hard to do in the Model S, but possible in the dual-motor versions. It was nearly impossible in the RWD cars. However, the "rated" line usually corresponded with a value of 305 Wh/mile or so, and therefore didn't indicate what you needed to achieve with efficiency in order to make rated range.

So in summary, the rated range and rated efficiency numbers are kind of meaningless. Any conclusions you derive from those numbers are also kind of meaningless.

SomeJoe7777: Couldn't have said it better myself. I don't see the point of trying to get a rated capacity to compare it between two cars.

 

[NewTMSMan]

I have both a RWD Model 3 and a Performance+ Model 3. I have a TED (The Energy Detective) unit that can measure kWh at the circuit breaker panel.

Any chance you could test both and report back even over a fixed % charge range for both to check actual charge vs change in %?

 

[NewTMSMan]

SomeJoe7777: Couldn't have said it better myself. I don't see the point of trying to get a rated capacity to compare it between two cars.

Pretty simple, either Tesla reported Rated Efficiency is incorrect or the RWD and Performance Model have different available battery capacities. Would have thought that was pretty clear by now.

 

[JeffK]

Only 66 kWHr with 110 WHr/mile and 606 miles.

Perhaps you didn't watch the video. The car showed it used 75 kWh thus disproving your math.

 

[RyanT]

I agree with SomeJoe7777. Just because you hit that line on the energy graph doesn't mean you'll get 310 miles. I've verified this with my Model S on a number of occasions (I would have to do better than it to get the rated range).

 

[SomeJoe7777]

Any chance you could test both and report back even over a fixed % charge range for both to check actual charge vs change in %?

I can, but to get a good reading I'll need to do it when the battery is at least down to 50%. That only happens once in a while on each car, so it might take a while. Also, the P3D+ is at the detailer right now getting window tint, paint correction, PPF, and ceramic coating, then it has to go get a dashcam installed. Won't have all that finished for 1-2 weeks.

 

[NewTMSMan]

I can, but to get a good reading I'll need to do it when the battery is at least down to 50%. That only happens once in a while on each car, so it might take a while. Also, the P3D+ is at the detailer right now getting window tint, paint correction, PPF, and ceramic coating, then it has to go get a dashcam installed. Won't have all that finished for 1-2 weeks.

Too bad no custom puddle lights .

If you do get the chance to check if both cars take the same energy input for the same change in % battery that would be great.

 

[SageBrush]

They may have the same battery, but it seems they do not have the same available capacity.

Range is usable kWh/EPA_rated_Wh/mile

EPA_rated_Wh/mile is the same across all Model 3

 

[NewTMSMan]

Range is usable kWh/EPA_rated_Wh/mile

EPA_rated_Wh/mile is the same across all Model 3

Uhh, want to provide a reference to that?

Again according to the Energy Monitor screens in the Model 3 the Rated Efficiency, Wh/mile in the Performance Model 3 is different than the RWD. They might not display the correct data, but I am using what Tesla provides.

In at least one case I have data for I can see a lower battery capacity available in the iOS App Remote S. 72 KWh displayed for RWD and 77 kWh displayed for Performance. Now n=1 data is not really useful, but if anyone else uses Remote S App and has a RWD Model 3, what does it display?

 

[JPUConn]

This thread makes me glad I use % battery remaining on the display vs rated range!