Supercharger - Burbank, CA (Service Center, no longer on nav map)

[roblab]

Agreed, I would never take that risk. That is cutting it way too close since the in-car nav does not factor in headwinds, air temp, and obviously cannot predict accidents that might require you to take a detour.

The in-car driver, though, CAN factor in all those things, and speed up or slow down according to what the car calculates for arrival battery percentage. A detour could be a game changer, but they are rare. One could pull over and wait, but that might be no worse than waiting at a supercharger. Chances are, it's fairly easy to figure out how far you can drive down the road.

 

[ecarfan]

our trip computer knows about elevations and calculates them into our estimate

Yes but the Tesla nav does not factor any headwinds, air temperature, any rain, possible delays due to accidents that of course it cannot predict, etc.

If you want to trust the onboard nav when it informs you that you will arrive at the next Supercharger with 2% charge remaining, that's up to you. I would never trust it that much, and I advise against anyone doing so.

 

[ecarfan]

The in-car driver, though, CAN factor in all those things

Yes an experienced Tesla driver can attempt to compensate for those factors. But I have read too many stories on TMC about experienced drivers who ran out of charge while incorrectly estimating the amount of charge it would take to reach their charging destination because they failed to realize how much extra energy was required due to rain/headwinds/cold temperatures etc.

 

[TaoJones]

Yes but the Tesla nav does not factor any headwinds, air temperature, any rain, possible delays due to accidents that of course it cannot predict, etc.

If you want to trust the onboard nav when it informs you that you will arrive at the next Supercharger with 2% charge remaining, that's up to you. I would never trust it that much, and I advise against anyone doing so.

New owners should read that, and this twice:

Nav will advise "good to go" at between 7-13% over rated. Blindly following this, especially in unknown territory, is foolish. Or naive. Or both. It is also a good way to get the "slow down to 45mph" message within 10 minutes of departure.

With headwinds and relatively flat ground, 1.3x wasn't enough. That said, generally speaking, +20% over rated is a good minimum threshold for the unknown, but +30% is better. Here's why: it's more efficient to use 15 minutes at SC A than to lose 30 minutes driving 25mph under the limit to get to SC B with 1-2%. Even if you get to 5% and speed up, that time is gone. Over the course of an 800-mile day, that adds up, which decreases sleep and in turn increases risk.

Moral of the story:

Don't trust Nav at least until you've traveled the respective leg *in both directions*, and do download and review the .csv file from evtripplanner.com, which takes a fair amount of the guesswork out of the equation by listing net elevation per leg.

Trusting Nav, or any sole source of info, is a great way to become acquainted with a flatbed.

 

[ShotgunF15E]

No. I don't buy that. An electric does not run out of juice when stopped, unlike our gas car driving friends' cars.

And up thread, concern about driving over to Tejon, maybe arriving with 2%. If we remember, our trip computer knows about elevations and calculates them into our estimate. Also, if we remember, one can make it to the destination if one can keep from creeping the speed up.

If a person could set their cruise to 65 instead of 70, or hey, even 60 instead of 65, the loss of time would be maybe half an hour instead of several hours. People don't think. Waiting is not our only option.

When I was stuck in traffic with the AC running because it was 108 degrees outside and all the fans were running to keep the battery cool too, it sure as hell does drain the battery. The only Tesla I've ever seen stuck on the side of the road was for the same reason. Two hours in gridlock in the middle of I-5 between LA and SF. No thanks. I'll charge a couple extra %...

 

[4SUPER9]

Yes but the Tesla nav does not factor any headwinds, air temperature, any rain, possible delays due to accidents that of course it cannot predict, etc.o.

Headwinds on the way to Tejon? A definitely possibility, with MAJOR impact on range. Rain? Uh, this is Southern California. No rain here in years. Where have you been?

 

[ecarfan]

Rain? Uh, this is Southern California. No rain here in years. Where have you been?

I grew up in Southern California and am aware of the weather, and of course it does in fact rain there as I'm sure you know.

My point was that the onboard nav does not take into account multiple factors that can effect real world range and owners need to be aware of that.

 

[whttiger25]

I had a fierce headwind driving north down the Salinas valley on Sunday that took about 6-7% away from my expected range, driving a reasonable 70mph.

 

[4SUPER9]

I grew up in Southern California and am aware of the weather, and of course it does in fact rain there as I'm sure you know.

My point was that the onboard nav does not take into account multiple factors that can effect real world range and owners need to be aware of that.

I got your point. I was just making a joke. Not a good one obviously.
Seriously though, I have not seen any rain there in So Cal hat was significant enough to change range here in several years. I miss it

 

[whttiger25]

I got your point. I was just making a joke. Not a good one obviously.
Seriously though, I have not seen any rain there in So Cal hat was significant enough to change range here in several years. I miss it

What about rain reduces range? Is it additional drag? Lower temps?

 

[4SUPER9]

What about rain reduces range? Is it additional drag? Lower temps?

Oh Rain definitely does that. I have seen it myself when I was driving out of town. My point is only that we are in a horrible drought, and I am done with it. El Nino was a total bust down here.

 

[whttiger25]

Oh Rain definitely does that. I have seen it myself when I was driving out of town. My point is only that we are in a horrible drought, and I am done with it. El Nino was a total bust down here.

I ask because I'm a new owner and thus have not driven the car in rain yet

 

[Cosmacelf]

I am only guessing here, but with sufficient rain, the car tires have to continually splash the water out of the way as it drives, which might increase wheel drag, not to mention "air resistance" drag pushing not only wet air but also wet rain drops out of the way. Real rain does indeed increase drag noticeably.

 

[TaoJones]

What about rain reduces range? Is it additional drag? Lower temps?

Both. Rolling resistance, mostly.

If you really want to torpedo range, combine a high speed limit, any elevation, rain, dropping temperatures and a nice headwind. 100% of an 85 battery won't get you 190 miles. And slowing down (the most effective remedial action) only gets you so far, no pun intended.

I remember reading from Dr. Straubel's treatise about tires (probably still at tesla.com's blog section) that LRR accounted for up to 3% at a certain speed with the Michelins. But I don't remember much discussion about rain specifically. I'm wondering now only because I just replaced the OEM Michelins after 55,000 miles with OEM Goodyears (the first variant - not this Spring's new Eagle Touring variant about which little is known other than what's listed at Tire Rack). Presumably I'll take a 3% non-LRR hit, but as I make ready for Oregon in a bit, here, the word "rain" does come to mind. Fortunately, there are more SCs along the coast and there are already good Chademos where the SCs aren't.

 

[4SUPER9]

Rain has an impact on rolling resistance. It also has an effect on aerodynamics. Humid/wet air is thicker than dry air. The harder the rain, the worse range. Am I correct?

 

[ecarfan]

Rain has an impact on rolling resistance. It also has an effect on aerodynamics. Humid/wet air is thicker than dry air. The harder the rain, the worse range. Am I correct?

I would think a heavy rain, putting more water on the road and coating the car with water, would negatively impact range more than a very light rain..

Rain really does make a difference, and the onboard nav does not yet factor it in.

 

[4SUPER9]

I would think a heavy rain, putting more water on the road and coating the car with water, would negatively impact range more than a very light rain..

Both of these attributes make sense, but I was also making the assumption that rain increases air resistance and wonder if this is correct. It seems to make sense to me. Even without rain, I would think that humid air is thicker than dry air and may affect range (though less so than actual rain). Anybody here have any data on this?

 

[bxr140]

Even without rain, I would think that humid air is thicker than dry air and may affect range (though less so than actual rain).

Humid air is actually less dense than dry air--humidity is just water vapor (H2O) which displaces the heavier Oxygen (O2) and Nitrogen (N2) molecules that make up most of "air". Its why humidity rises.

Most of the efficiency loss in rain comes from the additional drag/rolling resistance on the tires as they push water out of the way. There's also some component associated with the vehicle impacting a zillion raindrops [which are denser than air] , but its probably pretty small.

 

[napabill]

You can't predict that with LA traffic with any certainty. You get caught in ONE traffic jam cause of a wreck and next thing you know YOU'RE on the evening news as the tool who ran his Tesla out of juice on the 405. No thanks. How much do you pad for SoCal traffic? Good question.

You're thinking of traffic backwards. Traffic jams are GREAT for range! You can drive 350 miles at 30 mph. It's when the flow of traffic is 70+ that you run into problems.

 

[whttiger25]

You're thinking of traffic backwards. Traffic jams are GREAT for range! You can drive 350 miles at 30 mph. It's when the flow of traffic is 70+ that you run into problems.

Not if you are running the air conditioning or heater.......