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Realistic Range Expectations in Crummy Winter Weather
- Thread starter jeffnorman
- Start date
ChadS
Last tank of gas: March 2009
I'm not worried about you, PBill, but for our lurking friends that don't have a car and are worried about exactly this aspect, there are two very important considerations:
1. If you have another gas car in the family (true for the vast majority of Model S buyers), there is no reason for this to ever be a problem. If you aren't positive you can make the trip in the EV, just take the gas car. Just like you take your MDX to Costco instead of the 3-series sedan - you never know which day the 96-pack toilet paper special is running.
2. The only reason #1 isn't the perfect solution is that you won't want to take the gas car. The Model S is much nicer to drive, and cheaper and cleaner to boot. Cottonwood pointed out how to easily handle this case:
No matter what kind of car you drive, you will be anxious if you come close to running out of fuel with no fueling station nearby. The way to avoid anxiety is...to not do that! Always plan on getting more fuel well before you run out. For an EV, you can do some complicated calculations like the ones I have HERE, but the easier way is to always leave 1/3 of your range as a buffer. Make sure you know of a charging stop within 2/3 of the miles that your car says you have. I always plan my charging stops no more than 177 miles apart, and I never have to slow down, turn down the heat, or worry about getting there. Never! Driving an electric car can really be worry-free if you just follow that one simple rule. *
* Yes, OK smartypants, you might still run out before then if you are, say, racing the car on a track, or driving at felonious speeds in sub-zero weather with the HVAC cranked up to Hades. I'm talking about people that are taking a trip and want to get there. See the link in my signature for more details.
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I drive a daily commute of total 110 miles. Speed limit is 60, traffic normally runs in 72 for 80% of the commute. My expectations was 330 wh/mile in above 40F. And in temps around 40F this is what the car consumed. Now that the temps have dropped down below 20F. The car only uses 5% more energy. The only thing that eats range is short trips when parked in the cold for 30 mins at the time. The energy consumed then for the first miles are trough the roof. But for long trips im not worried anymore at all.
Al Sherman
It's about THIS car.
First, a plug for ChadS' link. He gets it, he's experienced, and his logic works. Very useful in practice, and theory.
I do the same distance drive (7 Miles one way) almost every day. I'ma very conservative driver and love the energy game. In the warm months I get 260-280 wH/mi both ways. In cold months (when you use heat and defrost) I get 300-330. I'm too lazy (absent minded) to preheat and sometimes battery and cabin warming can take the whole trip in extreme conditions. When the pack is cold, and you use heat and defrost the energy usage goes way up, and 7 miles generally wont be enough to average it down even if you drive conservatively. Your numbers seem completely in line for that short a trip in cold ambient temps. You'll be pleasantly surprised at how the numbers drop when the weather warms.
I do the same distance drive (7 Miles one way) almost every day. I'ma very conservative driver and love the energy game. In the warm months I get 260-280 wH/mi both ways. In cold months (when you use heat and defrost) I get 300-330. I'm too lazy (absent minded) to preheat and sometimes battery and cabin warming can take the whole trip in extreme conditions. When the pack is cold, and you use heat and defrost the energy usage goes way up, and 7 miles generally wont be enough to average it down even if you drive conservatively. Your numbers seem completely in line for that short a trip in cold ambient temps. You'll be pleasantly surprised at how the numbers drop when the weather warms.
Cottonwood
Roadster#433, Model S#S37
Yours is a nice simple rule, and for those not wishing to do mental math, adjust for altitude, etc, its a good rule. With 28-mph, 40-Amp charging at 14-50, 50-Amp RV Park connections, it seems backwards but you can sometimes make a trip faster by slowing down. The Silverthorne Supercharger helps me a lot on my Pagosa-Boulder runs, but I hate hanging out for hours at an isolated RV Park. That's why I'm getting the 50-mph, 70 Amp J1772 put in for me and other Colorado Model S users in downtown Salida. Because of scheduling issues with the electrician, its not there yet, but should be there any day now...
My personal rule is a reserve of 20% more rated miles than my distance to go (corrected for altitude) and is growing. I am willing to start a trip with less, but need places to charge if I can't get to that 20% and growing threshold. I use a free app on my iPhone that gives me GPS altitude and I know the altitude of my destination. 6 or 7 rated miles per 1,000 feet, and 20% are pretty easy calculations to do in your head if you like that kind of stuff. :wink: If not, the 1/3 left in the battery is a fine rule.
Superchargers are a wonderful thing. 70 and 80-Amp J1772's and dual chargers are a nice intermediate web. Living in a remote area of the country (the 4-corners region), that's life. Its like a gift from heaven that the Farmington Supercharger appeared in the 4-corners region for Elon's trip. :biggrin: Even so, I think the Pagosa and Salida 70-Amp, J1772's will help me and others for some time to come. See Farmington, NM to Silverthorne, CO with intermediate stops in Pagosa and Salida - Google Maps They just aren't there yet, and I am willing to hypermile in the cold for now.
ChadS
Last tank of gas: March 2009
Agreed, Cotton - my simple 1/3 rule is mostly about relieving range anxiety in newbies and letting them know that yes, it is easy to get where you are going in an EV. Being simple it is easy to communicate, but of course simple things don't always carry all relevant information.
For existing owners that want to know how to get there quickly, slowing down (and/or turning down the HVAC) can indeed be a useful tool when using L2 charging. That's what I love about Superchargers, you don't even need those footnotes anymore...I hope your area gets covered soon!
For existing owners that want to know how to get there quickly, slowing down (and/or turning down the HVAC) can indeed be a useful tool when using L2 charging. That's what I love about Superchargers, you don't even need those footnotes anymore...I hope your area gets covered soon!
jcaspar
Member
Hypermiling in the Winter...Brrr
Yesterday, I drove 228 miles with 2,000 feet elevation gain (12-14 equivalent miles, total 240 equivalent miles) in on a range charge of 255 miles in a P85, arriving with 13 miles left in the battery. The temperatures on the route ranged from 40˚ F. at the start to 12˚ F. on some passes, and probably averaged 26˚ F. or so.
The route was from the 70 Amp J1772 in Pagosa Springs at 7,000 feet to the Supercharger in Silverthorne at 9,000 feet. (169 N 7th St, Pagosa Springs, CO 81147 to Silverthorne, CO - Google Maps) I had hoped that the 70 Amp J1772 would be installed in Salida for this trip, but the electrician was delayed and I needed to get back to Boulder. :crying:
Range Consumers:
- Freezing Rain and Road Spray that Require the Defroster - Going over Poncha Pass, the temperatures dropped to 22˚ F., some freezing rain and/or road spray started icing up my windshield and obscuring my visibility, and forced me to go to full, high defrost, and turn off range mode to be able to see. In 10 miles, I lost about 4 miles of reserve range.
- Slush - Driving through slush is a real drag, literally. Going over Wolf Creek Pass there was a mixture of hard packed snow, wet roads, and slowly melting snow in between. I could feel the tires cutting through the slush. To minimize losses, I tried to keep the wheels on the hard pack or on the wet pavement. Even so, with the 45 mph speed limit over Wolf Creek, I am usually able to build several rated miles in the crossing. Yesterday, I lost a mile or two. Luckily, the lowest temps were about 27˚ F and I was able to rinse the spray and slush off of the windshield with the deicer, windshield fluid.
- Cold - Cold uses extra energy to keep the cabin and battery warm. I started just as a range charge ended, so the battery started warm. Also, during the range charge I turned on the climate control and set the temperature to 77˚ F. for about 40 minutes to store as much warmth in the cabin as possible. For the first 30 minutes of the trip, I was able to drive with the climate control off, and was comfortable with this stored heat. As the outside temps went down, I had to turn the heat on and off at its minimum 64˚ F. with the "blue, cool" defroster mode on to keep the moisture from my breath from fogging up the inside of the windshield. I wish the temp could be set to lower than 64˚ F. After the first half hour, I drove with my fleece, wool cap, and gloves on. The seat heaters are a good way to stay warm without using a lot of energy. I found that putting my fingers between my leg and the warm seat was a great way to warm cold fingers.
- Loss of Aerodynamics from Ice - See the picture below. I did not realize that I had this much ice in the wheel wells until I went over 60 mph on the descent off of Fremont Pass, the car (5.6) went into "Low" suspension mode, and the road pushed the suspension into compression. Boy, was that I surprise when the studded Hakas started grinding into the ice. I had no idea what was causing the horrible sound until I stopped and walked around the car. BTW, when over 50 mph, the car will not let you force it back to "standard" height with 5.6.
Range Extenders
- Slow Down - I knew this trip was going to be a challenge. Depending on how I felt I was doing, I set my maximum speed somewhere between 50 and 55 mph. Only after crossing the last pass, Fremont, when I knew I had Silverthorne made, did I take the speed up to 65 and 70. It was great to drive at speed with the heater blasting. I would have arrived with closer to 20 in the battery without this extravagance.
- Tail Winds - The effect of tail winds can be huge. After the big loss of range over Poncha Pass, and with the temperatures dropping, I was about to pull into an RV park with 14-50's, but as the park came into sight, it has a U.S. Flag out front that showed I had a great tail wind my direction. The forecasts were for this wind to keep going over Fremont Pass, so I decided to push on. Between Leadville and Fremont Pass, it was pure joy to watch the cold snow, ground blizzard push snow down the road in front of me.
- Hypermiling - Gentle, energy efficient driving helps. Accelerate and decelerate gently; when possible plan ahead and feather the accelerator pedal to decelerate without using regen. Use cruise control whenever safe. Gently enter and leave cruise control by matching the accelerator pedal position to the cruise speed when turning cruise control on and off.
- High Altitude - Density altitude is not quite as high when the air is cold, but its still better than sea level. For the aerodynamic losses, I probably have at least a 15-20% advantage on this drive that averages 8,000 feet over doing the same drive at sea level.
I did not know if I would be able to finish this drive on one charge, and there were at least two points where I was ready to stop and add a little to the battery. The fact that I knew of several places to charge along the way and was ready to do so if needed eliminated and range anxiety.
Plan ahead and bundle up. Hopefully, the next time I do this drive, the 70 Amp J1772 will be in Salida and I can drive a little faster and stay warmer. :smile:
Thanks! Great report. Very helpful for me in planning longer trips.
The key point, psychologically, is that this worry doesn't happen very often. I've found that I only have to worry about range on a road trip which I take maybe once a year -- or less! I worried about getting gasoline FAR more often than that, at least once a week.
Without research did my first long distance drive in the winter Chicago to Indianapolis..
A 200 mile trip used 240 rated range miles. Only 5 miles left on battery. 60-75 mph. Car prewarmed as we drove around before the trip. Heater on except the last hour of the trip. Range mode on.
Definitely had range anxiety the last half hour. Ouch.
On my return trip, with some suggestions from this thread, I cabin pre heated, charged to max range.
Probably most importantly, I slowed down so that I went only 60-65 mph with lots of cruise control. Heater used sparingly.
My 200 mile trip used only 200 range miles.
Much happier. No range anxiety whatsoever.
Slowing down by itself solved my range anxiety.
A 200 mile trip used 240 rated range miles. Only 5 miles left on battery. 60-75 mph. Car prewarmed as we drove around before the trip. Heater on except the last hour of the trip. Range mode on.
Definitely had range anxiety the last half hour. Ouch.
On my return trip, with some suggestions from this thread, I cabin pre heated, charged to max range.
Probably most importantly, I slowed down so that I went only 60-65 mph with lots of cruise control. Heater used sparingly.
My 200 mile trip used only 200 range miles.
Much happier. No range anxiety whatsoever.
Slowing down by itself solved my range anxiety.
At Colorado's altitudes, 62 or so seems to be the sweet spot where you can, in summer anyway, be confident of achieving greater than Rated range, without going so slowly that you're a hazard, at least in the lighter traffic on our rural interstate highways. But everything changes when the temps drop below freezing, as we all now know.
I have a regular Thursday evening route of 93 miles, with a 3-1/2 hour stop in the middle, over which in warmer weather I routinely consume right around 300 Wh/mi. Two weeks ago it was about 15 degrees F., and the trip averaged 343 Wh/mi; I preheated the cabin and battery before starting out, but the car wasn't plugged in at the halfway stop. This Thursday, the forecast is for temps to be really frigid, zero F. or below, with maybe a little snow. I'll report back on Friday with the results.
A friend of mine takes delivery of his P85 on Wednesday, the first day of the really cold weather. I will see him Thursday evening anyway, but I think I'll call him before he gets his car and let him know what to expect in the way of consumption, lest he think his new car is somehow broken.
I have a regular Thursday evening route of 93 miles, with a 3-1/2 hour stop in the middle, over which in warmer weather I routinely consume right around 300 Wh/mi. Two weeks ago it was about 15 degrees F., and the trip averaged 343 Wh/mi; I preheated the cabin and battery before starting out, but the car wasn't plugged in at the halfway stop. This Thursday, the forecast is for temps to be really frigid, zero F. or below, with maybe a little snow. I'll report back on Friday with the results.
A friend of mine takes delivery of his P85 on Wednesday, the first day of the really cold weather. I will see him Thursday evening anyway, but I think I'll call him before he gets his car and let him know what to expect in the way of consumption, lest he think his new car is somehow broken.
Cottonwood
Roadster#433, Model S#S37
I hope he does not have the super performance 21's, or if he does, is getting it delivered with some winter 19's. Those performance tires go to a glass like state at cold temps and can be very slippery, even on dry pavement...
Slow down and keep the heat on in Range Mode. There's no need to freeze!
Dropping your speed a couple of mph will compensate for heater use (assuming warm battery pack).
Mario Kadastik
Active Member
Ugh, thanks for the warning. I'm taking delivery of my Model S tomorrow and it arrives on the 21" wheels. Once registered at DMV I'm taking it to the tire shop to swap to 19" wheels and winter tires, but I will have to drive ca 6km in the city traffic and it's been snowing and it's a bit icy with temperatures around -2..+5C the past day or so. I'll probably keep 2-3x bigger distance than standard on this 6km trip.
I don't recommend you do this. Did 5km last year with the summer tires on a snowy road and I almost crashed the car two times. Performance summer tires are very dangerous in these conditions.
+1. Depends on the exact rubber compound, but be careful! I got caught in snow in my previous car last year, running Michelin Pilot Super Sports, and it was terrifying. Car tried to spin at 30 kph.
Mario Kadastik
Active Member
Remember, I'm > 1000km from nearest SC
And I didn't order winter tires from Tesla because I knew that they'd not get delivered in time (like all of Norway is waiting) so I organized my own set of wheels. Had Tesla sent me the TPMS in advance I could have organized the wheels to delivery location, but alas they didn't even send the second set with the car so I'll need to take the car to the shop and get the stuff managed out there. I've driven an Evo X with summer slicks in first snow conditions where it was ice with snow on top and loads of other cars with summer tires. I also drive cars on ice tracks etc so I do know some of how to handle a car that is on slippery conditions as we do get real winters here. I'll be careful and feather the accelerator and use regen for most of breaking.
even in moderate cold, the 21's are slippery. I've pretty much given up on them for up north, just not worth going back and forth. don't despair though, the 19's are almost just as cool ;~)... and in case you haven't seen the thread these are my favorite wheel option, allowing for tires with long life, better traction in varied weather conditions and improved range and they still look pretty awesome: http://www.teslamotorsclub.com/showthread.php/11271-19-quot-Turbine-Wheel-Solution/page48
