Range Anxiety how close do you cut it - and have you been bit?

[Big Earl]

1000 miles a week is an insane amount of driving to do in an electric car. Glad you have found a way to make it work.

I’m right there with him. 8,900 miles in just over 2 months. I’ve run it down to 9%, which I prefer not to do because it takes longer for the Supercharger to ramp up. The sweet spot is an arrival between 12% and 15%.

I think a lot of folks are in for a winter surprise. Be sure to leave yourselves an extra buffet and don’t plan on charging first thing in the morning (a cold battery won’t charge).

 

[Big Earl]

Auto wipers have been terrible for me compared to my Audi...

That being said, I did have a free range questions.

1. Why does range decrease 10-20% in the rain? I know @voip-ninja said resistance. Is that because the air is heavier, thus more wind resistance. Is it more tire friction. Both, neither?
2. With the cold, is it exponential the loss due to cold, linear, or does it plateau. I.e. do we lose say 20% at 40° and 40% at 0°. Or is it more so 40% across board. I assume linear.
3. This is the big one for me... Why does speed have such an impact. I know that is the killer with EVs but I still do not understand. My 3 is in the shop finishing up PPF and have my ice that I have yet to trade in. I get constantly 25 mpg. I tested today driving faster or slower constantly on highway (25 mph Delta) and noticed a 5-10% change in consumption at most. In my 3, that would be 25% or more. That leads me to believe wind resistance ia a big, but not the biggest factor. Rather the motor is that much less efficient at higher speeds. Am I correct here?

Thanks all!

Audis use a bespoke rain sensor whereas Tesla uses camera vision. The vision programming needs time to improve before it will perform as well as a dedicated sensor.

1.) range is reduced in the rain because it takes more energy for the tires to displace the water on the road’s surface. The same applies for snow.

2.) cold temperatures can have a varying effect on range. On a long trip, the range impact isn’t as bad as a bunch of short trips. The biggest factor is the additional heating required for the battery and interior. Short trips mean more heat cycles, which uses more energy.

3.) speed has such a big impact due to wind resistance, which increases at the square of velocity. Head winds and tail winds have a similar impact on range. Driving 70 MPH with a 10 MPH headwind is similar to driving at 80 MPH.

 

[Nate977p]

Audis use a bespoke rain sensor whereas Tesla uses camera vision. The vision programming needs time to improve before it will perform as well as a dedicated sensor.

1.) range is reduced in the rain because it takes more energy for the tires to displace the water on the road’s surface. The same applies for snow.

2.) cold temperatures can have a varying effect on range. On a long trip, the range impact isn’t as bad as a bunch of short trips. The biggest factor is the additional heating required for the battery and interior. Short trips mean more heat cycles, which uses more energy.

3.) speed has such a big impact due to wind resistance, which increases at the square of velocity. Head winds and tail winds have a similar impact on range. Driving 70 MPH with a 10 MPH headwind is similar to driving at 80 MPH.

On the wipers, I agree. But this seems to be one place they got a bit too excited; use the wiper sensor that works well instead if thousand of hours of R&D. I'd rather them take risks and most of the time they have a great, unique, class leading product. This is one that did not have that result, but will improve

1) Gotcha. So it is to due with tires, not a change in wind resistance.

2) Makes sense.

3) This I still do not understand. I understand wind resistance but the efficiency decrease on an EV seems drastically worse than my ICE. Is there really nothing else at play?

 

[Nik a]

Got down to 6% the other day, most days i finish up around 12-15%

 

[Big Earl]

On the wipers, I agree. But this seems to be one place they got a bit too excited; use the wiper sensor that works well instead if thousand of hours of R&D. I'd rather them take risks and most of the time they have a great, unique, class leading product. This is one that did not have that result, but will improve

1) Gotcha. So it is to due with tires, not a change in wind resistance.

2) Makes sense.

3) This I still do not understand. I understand wind resistance but the efficiency decrease on an EV seems drastically worse than my ICE. Is there really nothing else at play?

The ICE masks it’s efficiency loss by being horribly inefficient to begin with. If you test a gas car’s fuel economy drop in the rain, I think you’ll find that it’s similar to an EV ... about 10%.

It also doesn’t help that a lot of people don’t pay attention to their fuel mileage. I’ve spoken with many people who roughly estimate how many miles per tank they get rather than how many miles per gallon. The EV presents the information in a way that’s harder to ignore.

 

[lolder]

I actually may get one of those little Honda's....

They won't charge a Tesla.

 

[spinbackwards]

Range will start to be affected by temperatures below 60 as you apparently are beginning to discover. Absolutely rain will have a huge impact on range, probably cuts a minimum of 10-20% off due to the added resistance.

If making a longer drive in cooler temps where range/charging is a factor it's probably better to simply drive slightly below the speed limit if necessary to get the maximum range possible. You can also turn on the seat heaters and turn off the cabin heat which will also give you a few extra miles.

It somewhat boggles my mind that cars with 300+ miles rated range on a 100% battery charge still leave people running the battery dry but gee, here we are.

The first rule of Tesla club is buy the biggest battery you possibly can. I can only imagine the stories we are going to see when ma and pa kettle join the forum to piss and moan about their SR car leaving them stranded in the middle of Minnesota in the dead of winter.

Really? What's the payback in being a Tesla snob?

 

[brobinson]

I got down to 15 miles on both ways going from the Cleveland area to Baltimore. The built in trip planner really doesn't factor in all of the variables it needs to. I left from my house to breezewood PA (254 miles away) at 305 miles charge and arrived with 15. On the way back, I planned on stopping twice anyways, but inclement weather really forced my hand. On paper, I should be able to make it out there with only one stop.

 

[Nate977p]

The ICE masks it’s efficiency loss by being horribly inefficient to begin with. If you test a gas car’s fuel economy drop in the rain, I think you’ll find that it’s similar to an EV ... about 10%.

It also doesn’t help that a lot of people don’t pay attention to their fuel mileage. I’ve spoken with many people who roughly estimate how many miles per tank they get rather than how many miles per gallon. The EV presents the information in a way that’s harder to ignore.

That I think I can buy. If an ICE is typically 30% thermally efficent MAX, and wind resistance causes a 30% loss in efficiency, that will impact that 30% efficent ICE way less than a 95% efficent EV.

I have an extremely details Excel sheet of my MPG for nearly every mile I've driven the current car, so thats not me

On my other point, are the motors much less efficient at higher RPMs?

 

[Nate977p]

They won't charge a Tesla.

Why do you say that? I've seen YouTubes of them charging an S. I agree they would be very slow (~3 mph) but better than nothing if stranded.

Really? What's the payback in being a Tesla snob?

???

 

[Helmuth]

there are multiple threads on folks that had sudden car shut down at <20 miles left, no warning provided (model s and x)... take home message: be prepared for inaccurate battery range at less than 10%

Had it happen two weeks ago. Car shut down with 12 (rated) miles left (4% SoC). Less than 1 mile from the Supercharger I was driving to...
Had it towed to the Service Center since I could plug it in at the Supercharger without any energy left to unlock the charge port. They jump started the 12V battery m drove the car inside (which I didn’t know was possible) and charge it at their Supercharger, switched out the 12V battery (free of charge!!!) and I was good to go again!

 

[Saghost]

With an ICE you can throw a rock and find a place to refill the gas tank in about 5 minutes.

Unless you're driving in the Midwest or Mountain West, especially in the middle of the night. Worst range anxiety I ever had with any car was my 84 Chevy pickup in the middle of a Sunday night in rural Utah in the late 90s. Stations are 40+ miles apart, not always labeled clearly - and 90% of them were closed.

 

[voip-ninja]

Unless you're driving in the Midwest or Mountain West, especially in the middle of the night. Worst range anxiety I ever had with any car was my 84 Chevy pickup in the middle of a Sunday night in rural Utah in the late 90s. Stations are 40+ miles apart, not always labeled clearly - and 90% of them were closed.

Have lived in CO my entire adult life and have driven in rural Utah in the dead of night too. Still easier to find a gas station or even someone who will pull over and offer to give you a few gallons of gas than to find a place to charge electric car at anything better than a snail's pace.

 

[voip-ninja]

Really? What's the payback in being a Tesla snob?

Probably less drastic than the payback of being ignorant of the limitations of an EV and being left stranded in the middle of nowhere.

 

[lolder]

Why do you say that? I've seen YouTubes of them charging an S. I agree they would be very slow (~3 mph) but better than nothing if stranded.




???

The YouTube I saw the Honda wouldn't work but a Generac did. It costs $700 and weighs 50 lbs. I think paying attention to charge level is a better idea. In the M3, the battery icon turns orange with 20% remaining and red with 10%. A gas car fuel gauge usually reads empty when there is several gallons of fuel remaining in the tank which may be about 10%. Driving a Tesla to the red is like running to empty. Bad idea.

 

[rafacq]

Yesterday I got bit...

I was driving to the Ardmore, OK supercharger (on US 70 between Waurika and Ringling OK if you want to see on map), it was about 40 miles away and I had 70 miles on the battery. Seems like an fine margin, but do not really have a choice since there are not any other superchargers near. Well I got turned around on the highway. A tanker truck had overturned and the road was going to be closed for the rest of the day while they cleaned up an oil spill... With the required U turn and new route it would add about 60 miles to the trip... So, I turned around and started on the new route. The map of course kept wanting me to do uturns. Eventually the map changed to the new way and it was already flashing that I would have negative battery. Used search on the cell phone and found an RV park. Had to pay $20 to rent a stall and charge for about 2 hours using the 15-40 plug. So, it took about 3 hours longer (hour driving and 2 hour charging).

Lesson learned: when they finally get the Wichita Falls superstation built (still says 2018 estimate, hopefully next year), I will always stop for 10-15 minutes to get an extra 50-60 miles added. My driving route is Norman, OK -> Wichita Falls, TX-> Ardmore OK about 230 miles in an AWD model 3, usually gives me 25-30 spare miles range (highways speed limits from 65 to 75 on route). When winter comes I will probably have to slow charge at one of my businesses for a while (have a 14-50 plug) in Wichita Falls.

As you may know, there will be no SC in Wichita Falls, instead it is being built in Henrietta, TX, which is about 20 miles southeast of WF. Hoping it opens by the end of this month, Sep 2019.

 

[TomLee]

That I think I can buy. If an ICE is typically 30% thermally efficent MAX, and wind resistance causes a 30% loss in efficiency, that will impact that 30% efficent ICE way less than a 95% efficent EV.

I have an extremely details Excel sheet of my MPG for nearly every mile I've driven the current car, so thats not me

On my other point, are the motors much less efficient at higher RPMs?

My guess is that the Tesla M3 was designed to boost its efficiency in every aspects, being its shape, its weight, even its aero wheel cover. So small impact to the ICE car maybe a big impact to TM3. Tesla claimed the aero cover boost the range for 3% to 5% on it's own, while I've never heard any ICE car get a range impact by changing it's wheel.

 

[vickh]

Had it happen two weeks ago. Car shut down with 12 (rated) miles left (4% SoC). Less than 1 mile from the Supercharger I was driving to...
Had it towed to the Service Center since I could plug it in at the Supercharger without any energy left to unlock the charge port. They jump started the 12V battery m drove the car inside (which I didn’t know was possible) and charge it at their Supercharger, switched out the 12V battery (free of charge!!!) and I was good to go again!

did they say why it shut down with 12 miles? Charge port not opening is a big problem. Couldn't you or they do that manually

Why would the 12 V be a factor?

 

[vickh]

Audis use a bespoke rain sensor whereas Tesla uses camera vision. The vision programming needs time to improve before it will perform as well as a dedicated sensor.

1.) range is reduced in the rain because it takes more energy for the tires to displace the water on the road’s surface. The same applies for snow.

2.) cold temperatures can have a varying effect on range. On a long trip, the range impact isn’t as bad as a bunch of short trips. The biggest factor is the additional heating required for the battery and interior. Short trips mean more heat cycles, which uses more energy.

3.) speed has such a big impact due to wind resistance, which increases at the square of velocity. Head winds and tail winds have a similar impact on range. Driving 70 MPH with a 10 MPH headwind is similar to driving at 80 MPH.

Good points.
So what's the optimal highway speed?

How about windows down @ say 30mph vs AC?

 

[StellarRat]

Be sure to leave yourselves an extra buffet

Is that why they call you "Big Earl"?