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Life With 2013 Tesla Model S: The Good & The Bad At 600 Miles


2013 Tesla Model S electric sport sedan on delivery day, with owner David Noland

2013 Tesla Model S electric sport sedan on delivery day, with owner David Noland

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Two weeks and 600 miles ago, I took delivery of a 60-kWh 2013 Tesla Model S electric sport sedan.

I won't dwell on the ear-flattening acceleration, nor the magic-carpet ride and handling, nor the mesmerizing 17-inch touch screen controls.

Those features have been exhaustively  analyzed and reported by far more expert authorities than I. 

I'll just say that I was expecting a world-class cutting-edge luxury sport sedan, and that's just what Tesla Motors [NSDQ:TSLA] delivered.

But there have also been a few things I didn't expect. 

Here are some of the little surprises--good and bad--that I've noticed in the Model S so far.

Vanishing regen

One of the joys of electric driving is regenerative braking.  Lift your foot off the "gas" pedal, and the car slows aggressively as the drive motor turns into a generator and sends current back into the battery.

Strong regen is not only energy-efficient, but also gives the car a sporty, responsive feel, like engine braking in a  gas car in a low gear.  Electric-car drivers call it "one-pedal driving." With strong regen, you'll hardly ever touch the brake.

Different electric cars have different levels of regen.  The gentle Nissan Leaf is designed to feel like a standard car [but has two different settings for Regen, D and ECO].

The Chevy Volt has two regen settings, one that mimics conventional gasoline cars, and a second stronger one that allows for one-pedal driving. (I drive my Volt in this "L" mode virtually 100 percent of the time.)

Tesla's first car, the two-seat Roadster, had particularly strong regen, a popular feature with its performance-oriented owners.

The Model S, like the Volt, has two settings: Low, which mimics conventional cars, and Standard, which follows in the one-pedal tradition of the Roadster.

I was eagerly anticipating  the same sporty, responsive regen feel that had hooked me in the Volt.

Not so much, it turns out.

To my surprise,  regenerative braking in the Model S virtually disappears when the battery is cold. Starting out on a winter's day, it feels disappointingly like any old ICE car--even with the regen on the highest setting.

As the battery warms, the regen gradually increases. But it can take a maddeningly long time to get back to the max level.

Model S vs Volt

On a sunny 40-degree day last week, it took almost 25 miles of driving for full regen to come back. On my typical shorter trips around town, I never get it back. I'd guess that overall, perhaps only a third of my driving so far has had full regen available.

Blame the Model S battery management system, which is programmed to limit the charge rate when the battery is cold.

Under normal circumstances, abruptly backing off the gas pedal at high speed can send a jolt of up to 60 kW into the Model S battery. Tesla engineers believe such bursts of charge are not healthy for cold batteries, and therefore limit regen accordingly.

The Model S has a dashboard dial that shows exactly how much regen current is flowing back into the battery at any given moment.  Its maximum reading is 60 kW.

When regen is limited, a dotted line appears on the dial, and the  meter won't go beyond it. On a cold day, the dotted line starts out at around the 15-kW mark and gradually moves up to the 60-kW level before disappearing altogether when the battery reaches its normal operating temperature.

By contrast, the Chevy Volt's regen is unaffected by temperature. It's the same sporty feel, winter or summer. Apparently Chevy engineers don't see a problem with high charge rates for cold batteries.

Do they know something Tesla engineers don't? Or vice versa?


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Comments (49)
  1. re: tire pressure. Ford transit connect calls for 49 psi in the rear. (36 front)
    I guess if you average them the model S still wins :)
     
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  2. I wouldn't call the Transit Connect a car... That's weird about the drastically different tire pressures! Big rigs run 100+ psi I believe.
     
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  3. I think that's because the rear tires in the transit would get squished under a heavier load if they were at a lower pressure
     
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  4. Hi David. Regarding the overnight battery drain when unplugged; Could this possibly have to do with the inactive sleep mode feature in the Model S? Elon Musk was in Oslo, Norway recently and touced on this issue. He said something about this feature being currently disabled as Tesla is working on it. I believe he also mentioned this would be active again for the European deliveries.

    In short, the sleep mode will reduce the energy loss to around 0.3% (per day?), compared to several percent for when it is disabled. Check out this video from Elon Musk's visit in Oslo for more details on this and other issues: http://www.teslamotorsclub.com/entry.php/65-LIVE-Elon-Musk-speaks-in-Norway-about-Tesla-s-European-plans?bt=250
     
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  5. Exactly, the high vampire loads appeared after they disabled a faulty sleep mode. Once they fix sleep mode the vampire loads will mostly go away.
     
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  6. Battery draining overnight when unplugged: 2 different cases: 1) Warm weather, 2) cold weather.

    In both cases, the electronics pull something (10-200W?) just staying awake.

    BUT, in cold weather, I believe I read that the pack is kept warm constantly, even though it doesn't need to always be. The low temperature is actually ok for the battery. But before you can drive the car, the pack has to warm up. In order to keep the owner from having to wait to drive, the car keeps the battery warm all the time.

    Ideally, cold-climate customers should have an option in software to turn this behavior OFF, and schedule when the battery should be warmed and ready to drive in the morning.
     
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  7. The regen shutting off in the cold is interesting. It seems to work the opposite in my experience with BMW electrics. In the MINI-E and ActiveE the regen works no matter how cold it is, but if the batteries get too hot it will disengage. The reason being the charging process makes the cells even hotter so if they are getting too hot you don't want to make them even hotter.
    The MINI-E had a primitive passage thermal management system so when it was over 95 degrees out and I would have the A/C on and be driving aggressively, I could get the batteries up to 115 degrees and thats about when the regen would disengage. The ActiveE has a proper TMS so it's much harder to push it to where the regen diminishes.
     
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  8. Regarding disabled sleep mode, check out Elon's comments in this video at about 48:20: http://www.teslamotorsclub.com/entry.php/65-LIVE-Elon-Musk-speaks-in-Norway-about-Tesla-s-European-plans?bt=250
     
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  9. I will be joining you as a Tesla owner when their gen III product is sold. You do know that the Volt electric motors can work in opposition to each other to avoid over charge/regen to the battery.
     
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  10. The apparent loss of range is, mostly, not the battery being drained. It is that the cold batteries are less effective at delivery the energy, thus the estimated range goes down.
    A better measure of the actual drain is to leave the car plugged in, don't drive it for a full day after it is charged, and measure how much the car draws.
    It will 'refill' once a day. In my experience that has been about 4kWh (still a lot).

    In general most of the estimated range loss on the dash will return as you drive, warming up the batteries.
     
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  11. It's my understanding that the Model S, unless in sleep mode (which is currently disabled), tries to keep the battery a sensible temperature, so that you can just jump in a drive off without losing too much range. I think this is what is draining the battery when unplugged and using your house's electricity when plugged in.
     
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  12. Any car gets better efficiency in the warmer weather. Warm air is less dense than cold air, and the aero drag is reduced in warm air. Higher humidity air is actually less dense than dryer air at the same temperature, by the way. This is counter intuitive, I know. Also, higher elevations will have lower drag, as well.

    So at the very least, the Model S will coast better as the weather gets warmer. A related point: coasting is the most efficient way to drive, so learning to drive with the lowest regen possible (and putting it into "neutral" whenever possible) will yield the lowest energy consumption. I'm pretty sure that Tesla has regen on the brake pedal, right? So, when you need to slow down, regen is always available.

    Neil
     
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  13. The regen is on the accelerator, not the brake.
    As for coasting, it is efficient as long as it doesn't slow you down. If you have to speed up you will burn more energy regaining speed than you would maintaining it, wouldn't you?
     
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  14. You coast when you want to carry speed, like on down slopes. You use regen only when you need to slow down. This saves a lot of energy because you accelerate less. Using the kinetic energy of the moving vehicle is best used to keep moving the vehicle. When you use regen, you lose a fair bit of the energy; though obviously this is much better than friction brakes.

    Here's a comprehensive ecodriving guide:
    http://ecomodder.com/forum/EM-hypermiling-driving-tips-ecodriving.php

    Neil
     
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  15. Nope, the Model S brakes are strictly friction. Any time you use them, you're wasting energy.

    With the Volt, on the other hand, you still get regen with moderate brake pedal pressure.
     
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  16. Well, that is too bad. All other EV's out there at the moment have regen both on the accelerator and the brake pedals. A couple - the Honda Fit EV and the upcoming VW e-Golf have free-wheel coasting in the economy mode; which makes a lot of sense to me.

    Neil
     
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  17. Car and Driver disagrees with you about the value of regen on the brake pedal. They made a big deal about how the Tesla "brake only" was superior. They felt that nobody has mastered a smooth transition from regen to brake in one pedal. I have a Model S and a Prius, and after driving both for some time, I think I agree with them.
     
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  18. In terms of practical application, I disagree with your point about coasting being more efficient. Driving with high regenerative breaking in the Volt causes me to begin slowing earlier and, thereby, allows me to recapture more energy then I would through a later, harder break that's beyond the maximum regenerative breaking level.
     
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  19. There are more comments in this thread
  20. To correct the comments on the Nissan Leaf, it has two different settings for Regen, D and ECO. I live in Utah and leased our Leaf in October 2012. The average at the beginning was 26.3 kWh per 100 miles. As winter temperatures set in our lifetime average dropped to 27 kWh per 100 miles. We've been careful to wear warmer clothes on cold days and using the seat heaters and steering wheel heater rather than climate control whenever possible. Recently, our lifetime average returned to 26.3 kWh per 100 miles. I live in Utah and it isn't as cold here as many places, but my first winter experience with a Nissan Leaf has been very good.
     
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  21. Regarding no regen when the battery is cold, is there a way to precondition the battery and cabin? Like programming the car to warm itself up at 7 AM every week day if it is plugged in? You would think that should be a feature of a mobile app for the car.
     
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  22. Yes, there is. In addition, many report seeing a quicker return of regen.
    It all depends how cold the batteries are and how quick they warm.
    It doesn't really bother me, but the quickest way may be to just give the car a bit of 'range' mode charge at full amps.
     
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  23. The weaker cold battery regen never bother me as I anticipate very little and simply accelerate/brake as needed. However you are absolutely correct - simply give the car a bit of max range charging and presto, full regen!
    His other issues are either minor (to me) or being remedied by Tesla.
    BTW, was the author working on an ICE before taking that picture? Those jeans !!! :)
     
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  24. The overnight range drop has to do with the temperature of the batteries. Once they warm up the range should return to what you expected.

    Gas cars also change energy density based on fuel temperatures.

    This is normal behavior.
     
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  25. i was going to grill your ass hard when you were whining about regen not being as strong as you wanted it to be until i read page 2 about hypermiling and how coasting is a strong feature of this car.

    well written! Although you do realize both volt and the tesla uses lithium ion but what separates the two is the chemistry used to package the battery. I forgot what the separators were but they allow different characteristics to how the battery is used.
     
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  26. So... what's your address? ;)
     
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  27. David - Coasting fool. If you ever come to California: http://www.dmv.ca.gov/pubs/vctop/d11/vc21710.htm

    Any regrets about not getting the Tech package?
     
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  28. It's not that it's cold but because the battery is 95% or more charged why it's not regenning to protect the battery pack such high overcharging rates will do to it.

    Most of the damage to Lithium comes from charging over 98% or going under 5% charge. Neither is smart if you want your lithium pack to survive.

    Most EV batteries are murdered, not dying a natural death by owners doing such things to them. Like running a car without oil. By cutting regen until the battery can safely take it is the smart thing to do to keep owners from killing it.
     
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  29. Suggestion: keep a foil bag in the car, and slip the FOB into it before leaving. Remove from bag to start.

    Also, use the new phone app to warm the car before starting out, on "shore power". You will have full regen and accel right from the get-go.
     
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  30. if not a foil bag, a simple aluminum lozenge container.
     
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  31. Interesting observations you share. Thank you. One issue I was told was that in the Roadster the Wh/mile was only based on currents to the motor which does not include heater, thermal management or accessories loads. How is it done in Model S? I hope they have improved this.
    One reason that the Volt my take more early regen is that even fully charged the battery is at about 80% SOC so it may be able to handle more regen since it won't over charge the batteries.
     
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  32. chemistry is the primary culprit of limiting regen when the battery is cold. Your Volt does a slightly better job since it has a gas engine backup which uses 80% of that gas to provide heat. hard to stay cold that way.

    Other than that a great illustration of trade offs. A lot of LEAFers cry about TMS on the LEAF but with 21 Kwh usable, TMS is simply too much overhead. your Tesla will only see a slight improvement in Summer because hot air is less dense. temperature will do nothing for the batteries because that TMS is making it "summer like" in the battery pack 24/7.

    your mistake is taking the Tesla's range predictions too literally. you say you lose 10-20% in winter but you lose 25% over night? hate to say it but that is also winter lo
     
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  33. Actually, the Volt engine doesn't always comes up. It depends on the temperature and setting. But at least, the Volt battery is better "insulated" than the Tesla design.
     
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  34. I think the efficiency difference between your Volt and your Tesla S is probably due to heat usage and battery temperature. Does Tesla comes with heat pump?

    Volt uses a lot of power to keep the battery at constant temperature where Tesla allows the temperature of the battery to drop to a much lower level. The temperature differences also explain the regen difference in cold weather.

    Look at the design and location of the battery. Tesla S' battery pack is exposed under the car where the cold air will cool it much more efficiently than the Volt battery where most of that is hidden inside the car. I think Tesla was more worried about heat due to the power of the car AND the type of Li-ion battery used.
     
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  35. You didn't randomly quote people from other forums without contacting them for this article so that is a big improvement. Congrats.

    The Volt also only uses about half the battery pack so it has some place to put the extra energy from regen that a 100% charge on the Model S doesn't. If you use the mobile app to preheat your cabin while plugged in, it will pull power from the wall and your loss of regen will be lessened of completely eliminated.

    Sleep mode will be coming back so this isn't something to be overly concerned about unless you are going on a very long trip and leaving your car unplugged the entire time.
     
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  36. @David: If you have issues with High Gear Media editorial usage policies (your first sentence), please take them up with me. As you know, I can be reached at john (at) highgearmedia (dot) com.
     
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  37. I don't see a problem with quoting from a forum. If accurately quoted and used in a contextually accurate manner, what basis is there for complaint?
     
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  38. If the entire post is quoted, the post is linked so people can read the entire conversation and the author was attempted to be contacted to provide any context behind the post then yes, it is fine. Not doing so is the journalistic equivalent of using something you heard a random person say on the subway as a primary source for an article. People get paid to write reviews for books on Amazon and other sites so random posts on the internet are not the best source for a real journalist.

    As seen by that NY Times article where they pulled quotes from the internet including the first few sentences of a much longer post on a forum, it doesn't get the entire story since his posts changed after he heard what Tesla had to say on the matter.
     
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  39. @David, regarding the 'range drop' with overnight low temperatures. It is not quite what it appears as batteries capacity to deliver power varies with temperature. Warm the pack up (without pluging-in, or driving) and reported range will come back up. You can experiment by checking on clear cool morning, then rechecking in warm afternoon sun. This will provide you some insight into the battery pack 'hidden' capacity.
     
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  40. I think many others have already commented on the points I'm interested in so I'll just thank Mr. Noland for the perspective.

    I will note that even in a freezing cold Michigan winter, I'm losing only 20-25% of my range in my Volt, much less than Mr. Noland stated. But I also tend to use the heat sparingly to maintain as much range as possible, so that may be the difference.

    I'm a little puzzled about the different approaches to regenerative brakes, but we'll see what the long term approach ends up being. Both Tesla and GM (and others, of course) have some seriously smart people working on these and to reach very different conclusions is interesting. I just know that I'm not smart enough to know what approach is best.
     
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  41. In California it is illegal to leave your car running with the key in it. Not sure if this would qualify, but if someone did steal the car and had the key, it would be hard to prove you didn't lend them the car. I don't care how safe the area, kids will be kids and leaving any high power device that can kill people locked and loaded is less than smart.
     
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  42. Sorry, David, but to me it is one of the eternal mysteries of the universe - how someone dumb enough to "always leave my keys in my car" (and publish the fact on the internet) makes enough money to be able to afford a $70k car.

    I hope you have discussed this parking peculiarity with your insurance company!
     
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  43. @Martin: You haven't seen David's house, have you? [chuckle] I have. When he says "deep in the woods, at the end of a long driveway" -- he's not kidding. He'd know if anyone were coming well before the person got to his Tesla.
     
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  44. My guess on the overnight loss - the battery coolant system.
     
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  45. There really isn't any need to guess. The vampire issue is a result of the sleep mode being disabled in the current version of the firmware.
     
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  46. Habits are made to be broken. When switching from ICE to electric one must break the habit of pulling into a gas station.
    As for habits of leaving keys in the car, try assigning a place to hang FOB far enough away from the car that does not transmit to the Tesla.
    As far as regen is concerned you are a little too comparative to other vehicles that do not give quite the mileage or performance the Tesla does. I love my regen system and I love my Tesla. As a matter of fact my wife drove it the other day and I had to turn the regen down and put it in creep mode to accomodate her ICE driving habits.
     
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  47. With Tesla's latest software/ firmware update you can now choose when to charge your car........just set the time (probably for off-peak rates) plug it in and just walk away. And when Tesla does announce it's updates you are notified by a little yellow clock icon that when expanded gives you a choice of what time to perform update.
     
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  48. David, Thanks for info re. the key.

    your question: Different hot cold batt performance. Probably due to different batt types. They are not the same types of Li batt.
     
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  49. "Which raises the question: if you've got regen braking, why bother to coast? By shifting to N, aren't you losing the chance to put free energy back into the battery?"

    Why would you raise such a silly question? It's not a perpetual motion machine. Of course coasting is better than regenerative braking. That's true of any type of car, gas or electric or hybrid or whatever, with any kind of braking system, friction, or regenerative (electric, flywheel, hydraulic), whatever.

    Also, you don't need to put it in Neutral to coast. Just press the accelerator a certain amount and you will coast.
     
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