Destination remaining charge WAY off??

[Chasesmithrel]

I had a little over a 2 hour drive and was charging my truck at a supercharger to be able to get home. When I finished the charge it said I’d get home with 13% battery. It use to be pretty good at estimating it so I though that was enough and got on the road. After about 10 minutes of driving it dropped down to 11%. I always expect +-5% so I wasn’t worried then it dropped to 10% then 9% but it was dropping pretty quick. After about 45 minutes of driving it went from arrival charge from 13% to 5%. Luckily there was a charger on the way. When I stopped to charge again I was still about an hour from my house so just over half way and I looked to see if I didn’t charge what I’d get home with and it said 1%. So in just a little over an hour of driving it when from getting home with 13% to 1%.
I wasn't hauling anything, tire pressure normal, had it in hurry mode(which is what I always keep it in). Is this the newest updates messing up the estimates? Has anyone else experienced this?
fsd 14.2.2.4

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[pi_4x4]

could it be the wind factor? if you're heading into a head wind, it might not calculate it as accurately.

 

[mongo]

I had a little over a 2 hour drive and was charging my truck at a supercharger to be able to get home. When I finished the charge it said I’d get home with 13% battery. It use to be pretty good at estimating it so I though that was enough and got on the road. After about 10 minutes of driving it dropped down to 11%. I always expect +-5% so I wasn’t worried then it dropped to 10% then 9% but it was dropping pretty quick. After about 45 minutes of driving it went from arrival charge from 13% to 5%. Luckily there was a charger on the way. When I stopped to charge again I was still about an hour from my house so just over half way and I looked to see if I didn’t charge what I’d get home with and it said 1%. So in just a little over an hour of driving it when from getting home with 13% to 1%.
I wasn't hauling anything, tire pressure normal, had it in hurry mode(which is what I always keep it in). Is this the newest updates messing up the estimates? Has anyone else experienced this?
fsd 14.2.2.4

You were averaging over 70 MPH which cuts range, was there a headwind also?
If the nav added a Supercharging stop, preconditioning can use quite a bit of energy/ range.

 

[henchman24]

If you looked at the energy app, it should explain why.

It is probably wind/temperature/elevation/speed related. I have a stretch I routinely drive that is a ~45-50 mi slight uphill (~1500' elevation gain) the whole way that frequently has a crosswind... and I speed by ~7-8mph. Routinely the estimate is off 5-6% because of that. Staying to the speed limit would probably cut that in to ~1-2%.

Hurry mode will allow speeding of up to 10-15mph in my experience, keeping at standard is ~7, and chill is basically 2-3mph over. Putting it in chill would likely have made a big difference.

 

[devdrone6]

What was the temperature outside, that matters too in addition to what everyone else said.

 

[Chasesmithrel]

You were averaging over 70 MPH which cuts range, was there a headwind also?
If the nav added a Supercharging stop, preconditioning can use quite a bit of energy/ range.

I was averaging 82 (hurry mode) which I know is way less efficient but I have always kept it in hurry mode and its never been that far off before. It seems to get worse at estimating destination battery every update. Maybe it is only estimating for standard now and I have to manually adjust for hurry mode. Not sure. I'm just confused because its never done this too me before.

 

[mongo]

I was averaging 82 (hurry mode) which I know is way less efficient but I have always kept it in hurry mode and its never been that far off before. It seems to get worse at estimating destination battery every update. Maybe it is only estimating for standard now and I have to manually adjust for hurry mode. Not sure. I'm just confused because its never done this too me before.

Is I-26 70 or 75?
Nav planning is based on posted speeds so Hurry will mess that up.
The Energy tab breaks out where the differences between expected and actual energy use came from.

 

[Chasesmithrel]

What was the temperature outside, that matters too in addition to what everyone else said.

It was in the 40s, and I didn't notice the winds being too crazy or anything.

 

[henchman24]

I was averaging 82 (hurry mode) which I know is way less efficient but I have always kept it in hurry mode and its never been that far off before. It seems to get worse at estimating destination battery every update. Maybe it is only estimating for standard now and I have to manually adjust for hurry mode. Not sure. I'm just confused because its never done this too me before.

The range estimate is not tied to FSD profile. They don't speak to each other. It is tied to the route taking into account weather and assume you drive the speed limit.

Two things... first, the higher the speed, the more any weather variation will impact the range estimate. At 82, if wind is higher than anticipated or is from a slightly different direction, it will cause the estimate to be off (and generally I think the wind estimate is not great with the CT compared to most models). If the temp is a few degrees colder than expected, the truck will have to work harder at keeping the battery temps up.

Second, what SoC do you charge to? What is your typical drain? If your battery hasn't seen the top of the pack or the bottom of the pack prior to this in a while... there could be some slight BMS sway. The battery could be off a few percent very easily.

It was in the 40s, and I didn't notice the winds being too crazy or anything.

This will be part of it. Hurry mode forces the truck to keep the battery at full power potential. Meaning it has to scavenge heat to keep the battery above 50. This is in addition to keeping the cabin warm. So the heat pump is working harder. Chill and sloth FSD don't require the battery to be as warm and won't attempt to warm the battery until near or below freezing.

 

[Chasesmithrel]

In short I know that hurry mode is not efficient but I have always used hurry mode and it seems to be worse now than it has been. I've made this same drive many times and when I first got the truck about a year ago it would underestimate the usage and I'd get home with more than it expected (even in hurry mode). With every update it seems be getting worse and worse. Just curious if others have experienced that or if I have just had a few out of the ordinary drives in a row.

 

[SCTesla]

It has been extremely windy in SC the last 2 days.

 

[henchman24]

With V14, the speed cap got eliminated. So the switch from V13 to V14 in that timeframe likely would have a portion to do with any change in estimate. If you previously set it to say 80 and it goes 82-85 now, it could be a large impact. Beyond that, it is likely simple variation. You can check the normal things to be sure... but odds are it just happened to estimate wrong.

 

[Chasesmithrel]

With V14, the speed cap got eliminated. So the switch from V13 to V14 in that timeframe likely would have a portion to do with any change in estimate. If you previously set it to say 80 and it goes 82-85 now, it could be a large impact. Beyond that, it is likely simple variation. You can check the normal things to be sure... but odds are it just happened to estimate wrong.

You're probably right, now that I think about it it really started when the FSD changed from being able to set a speed. I use to set it to 80 on the interstate and it stays at 82 in hurry now. I didn't think it would make that big difference but that is about the time that the estimates started being wrong. I wish there was a way for them to communicate and account for me using hurry mode. I may just need to slow down

 

[mongo]

You're probably right, now that I think about it it really started when the FSD changed from being able to set a speed. I use to set it to 80 on the interstate and it stays at 82 in hurry now. I didn't think it would make that big difference but that is about the time that the estimates started being wrong. I wish there was a way for them to communicate and account for me using hurry mode. I may just need to slow down

Yeah, aero load goes as the square of velocity and dominates at higher speed
82 is 37% worse than 70
87 is 13% worse than 82 (5 MPH headwind)
82 is over double 55
Rolling resistance is fairly constant in Wh/mile
HVAC and vehicle electrical load Wh/mile decreases with speed

 

[CyberGus]

I drove across West Texas this weekend, where the speed limits are commonly 70-80MPH. Even in "Standard" FSD, I maintained 85MPH for long stretches.

I too noted my "Arrival SoC" dropping and dropping... because my efficiency value jumped from the typical ~400Wh/mi to over 700Wh/mi (sometimes peaking above 800!!!)

That's worse than towing

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