Lost 40 miles range on a 11mile regular journey?? New Model 3

[TimothyHW3]

No, you don't know what the answer is because you don't know what the capacity is. If you have a full pack it might be 105 if you have 5% degradation it might be 100. This is your problem in your calculation - you are guessing.

You think that the gauge is static, but it is not - it is based on available kWh . This is the reason people see lower mileage while charging to 100%. Because the formula is simple ,- available pack divided by a fix constant for consumption, which ones again is 153Wh/km

But since you don'tknow the constant and you don't know the available capacity, you can't make any predictions. Once again, the only way to answer your question is, if you tell me the exact kWh available via OBD and I will easily calculate it via the 153,Wh/km constant.

If you have a car with 15% degradation of bad BMS it might as well be 85miles or something...

 

[AlanSubie4Life]

No, you don't know what the answer is because you don't know what the capacity is. If you have a full pack it might be 105 if you have 5% degradation it might be 100. This is your problem in your calculation - you are guessing.

You think that the gauge is static, but it is not - it is based on available kWh and since you don't know the constant and you don't know the available capacity, you can't make any predictions. Once again, the only way to answer your question is, if you tell me the exact kWh available via OBD and I will easily calculate it via the 153,Wh/km constant.

Degradation does not affect the constant as far as we can tell.

You don’t have to agree with me. Go ahead and test it for yourself though if you want. Or not.

 

[TimothyHW3]

Ok, this is the last from me on the topic...

A constant is a constant, it never changes...

Formula to display range: Available kWh according to BMS divided by constant(153 to 154Wh/km never changing)

Example:
77kWh brand new car: 77/154 500km at 100%
75.7kWh degradation 75.7/154 is 492km at 100%

If you drive a brand new car without degradation with a consumption of 180Wh/km your gauge will be as follows.
77/180 or 428km instead of the rated 500km at 154Wh/km

And if you have a degraded battery it will be 75.7/180 421km instead of rated 492km if you were driving 154Wh/km

Hope it is clear for everyone now and it helps.

 

[AlanSubie4Life]

If you drive with exactly 154Wh/km for 480km your car will report 0

I disagree with this. You’ll be able to drive a maximum of about 471km (maybe as little as 463km) at that consumption as indicated on the trip meter (not the CAN bus), from 310 rated miles to 0. And yes, after that you will hit a reserve of some amount...hopefully.

It is of course possible the “constant” is nonlinear at the bottom end of the range - and then I would be wrong about this. But for practical day-to-day measurements of rated mile/km use, you’ll see something proportional to the above. I’ve only checked the constant over a range of 100 rated miles to 310 rated miles - never below 100.

 

[TimothyHW3]

Well, you can disagree with me, but not with the facts. These are the facts. The constant is clear and measurable.

And no, there is no "some amount of reserve", and there is no "hopefully". With a BMS fully working you will hit the buffer which is measured by the BMS and will give you about 3.4-3.5kWh(measured by OBD) which is exactly the 20km missing. This has been actually tested and prooves the "theory"
I would post the Video, but it is in Germany and too long and maybe will be too confusing for you.
The guy hit the reset on the trip at 0km remaining and he drove 28km with a consumption of 138Wh/km until the car shutdown. This was on a brand new car so he had about 3.7-3.8kWh buffer. If you actually do the math you will end up at exactly 154Wh/km and 3.8kWh buffer

 

[T3slaOwner]

No, you don't know what the answer is because you don't know what the capacity is. If you have a full pack it might be 105 if you have 5% degradation it might be 100. This is your problem in your calculation - you are guessing.

You think that the gauge is static, but it is not - it is based on available kWh . This is the reason people see lower mileage while charging to 100%. Because the formula is simple ,- available pack divided by a fix constant for consumption, which ones again is 153Wh/km

But since you don'tknow the constant and you don't know the available capacity, you can't make any predictions. Once again, the only way to answer your question is, if you tell me the exact kWh available via OBD and I will easily calculate it via the 153,Wh/km constant.

If you have a car with 15% degradation of bad BMS it might as well be 85miles or something...

Maybe there is something in this forum I am missing, but when you don't quote the person you are replying to it seems hard to know who you are addressing and what you are talking about. One of your posts referred to someone calculating "310*230" and I can't find that anywhere other than your post.

 

[AlanSubie4Life]

Maybe there is something in this forum I am missing, but when you don't quote the person you are replying to it seems hard to know who you are addressing and what you are talking about. One of your posts referred to someone calculating "310*230" and I can't find that anywhere other than your post.

That was me he was quoting. I stand by that statement: Again, I'm NOT saying the battery capacity numbers he gives above are incorrect, or the internal numbers are incorrect - I believe them (and the reserve capacity) to be correct. It's just that the trip meter appears to read low relative to those numbers (whether it actually reads low or not really isn't relevant actually - it is what it is - all that matters is how the trip meter corresponds to rated miles usage!).

See here for a datapoint from someone recently:

Verification of Wh/rmi constant

I've done similar experiments - except in the case of certain extenuating circumstances (lots of regen, significant battery temperature changes, etc.) it always comes up with around the same 230Wh/rmi constant (only applies to AWD Model 3 vehicles). Anyone can do this themselves if they don't believe me, so there's really no need to take my word for it, or believe me at all! (Long drive, battery at rough thermal equilibrium, drive, look at Wh consumed, divide by rated miles used (being careful to minimize rounding errors).)

 

[T3slaOwner]

That was me he was quoting. I stand by that statement: Again, I'm NOT saying the battery capacity numbers he gives above are incorrect, or the internal numbers are incorrect - I believe them (and the reserve capacity) to be correct. It's just that the trip meter appears to read low relative to those numbers (whether it actually reads low or not really isn't relevant actually - it is what it is - all that matters is how the trip meter corresponds to rated miles usage!).

See here for a datapoint from someone recently:

Verification of Wh/rmi constant

I've done similar experiments - except in the case of certain extenuating circumstances (lots of regen, significant battery temperature changes, etc.) it always comes up with around the same 230Wh/rmi constant (only applies to AWD Model 3 vehicles). Anyone can do this themselves if they don't believe me, so there's really no need to take my word for it, or believe me at all! (Long drive, battery at rough thermal equilibrium, drive, look at Wh consumed, divide by rated miles used (being careful to minimize rounding errors).)

I've lost the gist of the conversation so it doesn't matter to me what anyone was saying. I was just trying to make the point of quoting so people can figure out who is responding to what. Here even that is not always enough since the forum only automatically quotes the previous guy and nothing he was responding to. Adding that back in manually is not so easy and leaving it in automatically makes for long posts if people don't trim. But at least one level is good.