Some battery and range numbers to kick around

Some battery and range numbers to kick around

Okay so I tried the trip tracking feature on the model 3 performance today. According to today's numbers I used 13 kW out of the battery and went about 61 miles. I didn't feel like I drove anything out of the ordinary, if anything maybe a little more aggressively.

So with those numbers that means I get about 4.69 miles per kilowatt, which means that if I drove the same I should be able to get about 351 mi given that I have a 75 kilowatt battery in this car.

Here's the weird part. Even though 13 kilowatts being used means I should have 80% of the battery left, The Tesla is telling me that I only have 71% left. And it's estimating that I only have 220 of range left.

At the end of the day, I think Tesla's own estimation of the range is not very good. Just keeping the numbers as simple as possible and using the amount of kilowatts you use out of a 75 kilowatt battery, the Tesla is just wrong and it's estimation of 71% left. Where does that number even come from?

Anyone else have any experiences like this? Or know what's going on? It seems like Tesla wouldn't want to freak everyone out all the time with its overly conservative range and percentage numbers.

gballant4570 | 25. November 2019

Perhaps Tesla actually knows how many available kw is in the battery. And don't forget rounding - can make a difference when you're rounding to whole kw. Add that to the not well known method of estimating SOC miles, and it's never gonna add up very nicely. But the car's data may well be just as good as the way you are arriving at yours.

chase.chick | 25. November 2019

See I think that the amount of kilowatts used divided by the amount of kilowatts in the battery is a pretty hard and fast metric. The battery is either a 75 kilowatt battery or it isn't. And unless the trip app is giving me bad numbers on how many kilowatts I use, I'm not real sure where to go from there. Even if I round up and say I used 14 kilowatts, that still doesn't make up the difference.

Bighorn | 25. November 2019

Let’s speak the proper terms if this is going to make any sense. The battery capacity is in kilowatt hours. KW is instantaneous power. 13 kWh is approximately 18% of the 72.5 kWh capacity. I suspect you were starting at the 90% SOC and therefore, nothing to see here.
71% * 72.5 kWh * 1 mile/234 Wh = 220 miles. Again, totally expected result.
Tesla’s math is just fine.

gballant4570 | 25. November 2019

chase.chick, the Model S and X battery sizes were part of the car config names - but they were nominal numbers, not exact numbers. The Model 3 battery size has not been mentioned or confirmed by Tesla, but has been guessed at. Some guesses have been more educated than others, and there used to be a number of discussions on this forum about the subject. Available kwh for driving in the LR config has been estimated to be as high as 73, but that is not a known fact. The total capacity has been estimated to be around 83 kwh, but using the nominal convention that would be stated as 85.

Bottom line, when you calculate using 75 kwh you will not be accurate. Not much hard and fast about it.

FISHEV | 25. November 2019

" I think Tesla's own estimation of the range is not very good."

I think you'll find the Estimated Range is pretty accurate. You can play with it by selecting last 5, 15, 30 miles in the Energy Display to see different iterations based on the last miles driven.

It's getting colder now so that also affects the range.