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"Range Anxiety" Mitigation Program (RAMP)

Discussion in 'Model S' started by ElSupreme, Sep 5, 2012.

  1. ElSupreme

    ElSupreme Model S 03182

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    When I was first looking at the Tesla I was convinced I HAD to get the 85kWh battery to do what I needed. After 8 months of logging my daily travel I think I can comfortably get the 40kWh. I drive close to 20,000 miles a year. I drive 55 miles round trip for work every day. You might be surprised how far a 40kWh pack can get you.

    So I have been keeping a log of all of my driving since January 13th of this year. That makes 236 records so far. I have a 3.5 week period where I didn't 'drive' as I was on vacation or in bed with a fever.

    I have a bunch of distance data. I took the total distance driven every day. My average daily trip distance is 80.8km (50.2 miles), if you take out the 3.5 weeks of not driving you get 87.8km (54.6 miles). Maximum was 673.6km (418.6 miles). My really long trip was to a funeral in the middle of nowhere Georgia about 100 miles from Augusta. An 85kWh Models wouldn't have made it. I was not able to charge at home over night 3 of the days. And 2 days I would only be able to charge at 120V in my dad's garage. But none of the non-charging days would cause any distance issues.

    I am logging everything to determine if I can get a 40kWh pack. Right now it looks like that is easy. I have 3 warning levels (for each battery), drive it like I stole it, drive it at 65 on the interstate, and hypermile (used 55 mph number from Tesla). My distances were estimated a long time ago (before the EPA range on the 85kWh) but I believe them to be still fairly good. The 40kWh ranges are 95.5 miles, 119.3 miles, 160 miles respectfully. As a reference I have the 'drive at 65' giving 223.7 miles for the 85kWh pack, which is pretty close to the MT number. I fully plan on charging in range mode (at this point) if I am going to drive over 100 miles in a day.

    As of today (236 records, 217 non vacation records) I have exceeded the 95.5 miles 6 times. I have exceeded the 120 miles twice. Once was the 400+ mile trip. The other was 3 separate trips on a Sunday. I was at home for about 4 hours between trips. I could have easily gotten enough charge to make it through the day. I could have easily taken my wife's car on one of the 3 trips. So I don't count this as a true failure.

    A lot of my trips are very close to the 95 miles. But I currently drive my car down past "0 miles to empty" about 80% of my tanks. And about 1/2 of my fill ups are with less that 1 gallon remaining in the tank. I have yet to run out of gas (except on gas station property, twice!) in a car. So I am very comfortable running to the very edge of range.

    I drive roughly 20,000 miles per year (a little low this year due to the almost 1 month of not driving). So I drive a lot. My driving is pretty well balanced, as in I drive roughly the same every day. But if you are feeling pressured to get a bigger battery I would really think about your actual driving habits. You might not need as much as you think.

    I plan on driving slower and 'better' as the battery degrades, as I currently drive really fast. I also plan on purchasing a replacement battery after about 150,000 miles if my driving stays in the same distance range. I expect about 80% capacity after 150,000 miles or 8 years.

    Do what you want with my spreadsheet. It may help you truly understand how far you really drive.

    View attachment RangeAnxietyMitigationSheet_2012-09-05.xlsx

    Some notes on my file.

    All distances are in km not miles.
    I have a running fuel, and predicted fuel cost at the top.
    The top green line has limit distances.
    The Reference tab can change your % multipliers for how far you think your car will go.
    Lots of things are automated. I only enter 4 columns: 'Distance', 'Notes', 'Fuel Cost', and 'PM Charge'.

    The little colored dots change color automatically. Green if you have plenty of range to spare. Yellow if you are within 25km (15.5 miles) from empty. Red if you go over the stated distance.

    Off to the very right I have a 70 mile LEAF range. As you can see I regularly put it into the red. And almost put it into the yellow every day.

    ASP = The plant where I have been working
    Ken = My office in Kennesaw, GA
    ATL = Atlanta Airport (ATL)
    Soccer = Varies in location all over Cobb County
    GT = Georgia Tech
    Publix = BEST GROCERY STORE EVER. Based out of Lakeland FL
     
  2. spatterso911

    spatterso911 MSP#7577 **--** MX#1891

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    Very slick, indeed. I think I'd still get the 60 if I were in your shoes. The unknown in your equation is time and it's effects on your 40 kWh battery. It forces you to make changes on the fly, and no one knows how this battery truly behaves as of yet.
     
  3. RDoc

    RDoc S85D

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    Keeping a log is a very good idea, particularly for those of us waiting for an X, lots of time to gather data.

    One thought on batteries. As has been mentioned elsewhere, the 60 kwh has the advantage of access to Supercharging, which isn't available for the 40 kwh batteries. IMHO, the Supercharging system may well be the major factor in not only what size battery to get, but Tesla's overall success. If it is a nationwide comprehensive system, particularly if it included battery exchange as well as charging, it could change the entire EV market.
     
  4. dsm363

    dsm363 Roadster + Sig Model S

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    I'd go for the 60 kWh as well and keeping track of your range would never be an issue with almost all of your trips. You'll may want Supercharger capability in the future as that would make a 400 mile trip a one stop charge up kind of trip. If you had a 10 mile round trip commute then the 40 kWh pack would be fine but you'll be cycling a little less than 50% of your standard charge in a typical day every day so the added warranty and range of the 60 kWh pack might be helpful 8 years from now.

    You are correct though that you could easily make a majority of your trips now and in the near future on the 40 kWh pack but think that the 60 kWh pack adds plenty of future flexibility and might be worth the upgrade. I've never regretted having about 200 miles of range in the Roadster and have taken a few 200 mile trips so the capability is nice. Everyone's driving needs are different of course so keeping your log is an excellent idea.
     
  5. ElSupreme

    ElSupreme Model S 03182

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    Here are two pics of my logbook I keep in my GTI.

    Log01.jpg
    Log02.jpg
     
  6. dsm363

    dsm363 Roadster + Sig Model S

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    You said all those distances are in km not miles, right?
     
  7. mnx

    mnx 2013 P85

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    This may or may not be obvious but it's more important what your driving habits will be in the future, then what you have recorded in the past. However, if nothing significant changes in the lifetime of your Model S, then no worries.
     
  8. ElSupreme

    ElSupreme Model S 03182

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    Yes all my distances are in km. An old college / bicycle habit. Plus as an engineer I hate standard units. Heat and power / energy are so hard using non SI units.

    - - - Updated - - -

    This is very true. I truly hope that I won't drive further than I am currently. The only saving grace is that I can drive 80 mph to and 75 mph from work currently.
     
  9. efusco

    efusco Moderator - Model S & X forums

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    First, well done!
    It looks like a 40kWh pack would work for you, but I think you'll be pushing things after battery range starts to deteriorate and if you find you are running AC and driving more aggressively than you currently do (which is very tempting in an EV). Thus, I'd be leaning toward the 60kWh pack in your position for those reasons as well as the others mentioned above. It also gives you a bit of a cushion in case the car fails to charge one night (breaker thrown, you forget, power outage, staying at a friend's place, whatever).

    That said, if cost is a significant concern I certainly think you could easily make due with the 40kWh pack and just accept that a few times per year you'll need to use an alternate vehicle.
     
  10. dsm363

    dsm363 Roadster + Sig Model S

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    You can easily fit the 40 kWh into your driving currently as mnx pointed out. It really is a matter of how much you want to future proof your car with bigger pack and battery warranty.
    At 20,000 miles a year you're exceed the battery warranty in 5 years with the 40 kWh pack and in a little over 6 years with the 60 kWh pack but add Supercharger hardware.


    With driving speeds like this, added range would help.
     
  11. neroden

    neroden Happy Model S Owner

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    This is why I will probably get far more battery than I need: There isn't a huge track record on any of these batteries.

    I have a driving pattern of driving extremely little every day, maybe 130 miles every month or so, and then occasionally suddenly needing to drive 220 miles or more, NOW, under arbitrarily bad road conditions. While the 60 kWh battery should be fine for that, it could be iffy; if its capacity drops over time, if driving on cold, snowy roads with the heater on uses a lot of energy, if I don't have time to charge up in range mode... I can easily come up with worst-case scenarios where I'd be very nervous without more battery. I suppose I could rent cars for such occasions, but that's less than attractive.

    Of course, a log wouldn't help alleviate this type of range anxiety. I already know I'll only want the extra range from the 85 kWh on rare occasions. :redface:

    I was thinking of starting a thread on battery management if you underuse your battery. Will it hurt the 85kWh battery if I only drive 15 miles a day practicaly all the time, with only the monthly longer trip? Does the software balance the usage of the cells for this scenario, or will I burn out some of my cells while others remain unused?
     
  12. dsm363

    dsm363 Roadster + Sig Model S

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  13. Zextraterrestrial

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    I went with way more battery than I need. But,the performance angel on my shoulder zsigned my mvpa(I hope he has the $)

    Nero, your battery should last 100years at that rate(if we do)

    ElS. Nicelog, did u say computer engineer?
    I have an XL sheet with every fill/mileage and location for my rav4 for 4 +years.
    But I'm civil E+ into chem & other stuff like art&gardening beer and bread
     
  14. ElSupreme

    ElSupreme Model S 03182

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    I am a Mechanical / Process Engineer. I kept a log of every fill up and tank for my Jetta TDI that only lasted ~20 months before a Maxima ended its life.
     
  15. Raven5000

    Raven5000 Member

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    I'm getting a performance and driving hard everyday to work. Hopefully I will get at least 180 miles with a 85kw pack. my commute is only 80 miles round trip but I want the extra battery so I never have to worry. In the sf bay area speed limits are 65 and almost everybody does 75. That's real world driving! Going 55 all the way to work I don't think so. What's the point of buying a high performance car if you can't drive it that way! Just my opinion.
     
  16. elecblue

    elecblue Member

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    Nice spreadsheet. Looks like the Model S would work (any battery size), but the Leaf would not. Having rented one in LA this summer I can vouch for that. Glad I didn't pay $40k for a car that can go about 70 miles on a charge. My EV conversion could do that and was home-built, so not much to brag about for Nissan (from a range perspective).
     
  17. jkeyser14

    jkeyser14 Member

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    Must be nice. Here in MD/DC rush hour traffic I'm thrilled any time the speed hits 40 mph.
     
  18. ElSupreme

    ElSupreme Model S 03182

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    #18 ElSupreme, Sep 24, 2012
    Last edited: Sep 24, 2012
    I tweaked my numbers based on the EPA 265 mile range. And some of the road tests getting mostly that. I also put in 85% of battery pack in standard charge mode. All of which gave me a little more range.

    The only real assumption left is if the 160/240/300mile ratios hold true to the 40/60/80kWh packs on normal driving.

    I feel confident that the 40kWh will get me everywhere I need to go. That being said if I stretch and get the 60kWh pack I will have a huge range buffer on ALL of my driving and can drive in whatever style I want while driving to both sides of Atlanta in a single day.

    I plan on crunching some financials in a month or so to really see what I *want to* afford (and probably *can* afford, as I feel they might be the same on this purchase). I got married and took my honeymoon in August. So I don't actually know how much money I have at the moment. My financials have stabilized this last month so hopefully I can gauge how much I can purchase.

    The numbers I tweaked:

    On the reference tab I am using 80% as my multiplier instead of 75% (top left of table) as it gives 240 miles on an 85kWh pack driving in range mode (I wouldn't get 265 as I travel at high speeds on the interstate). I also changed the formulas in cells J4-J6 as they used 80% battery usage in standard mode, which is actually 85% in the Model S (0.8 -> 0.85). I end up with ~110 miles on a 40kWh pack in standard mode.

    EDIT: Right now I want to cut off all my DirecTV and use that payment towards the 60kWh upgrade!
     
  19. gg_got_a_tesla

    gg_got_a_tesla Model S: VIN P65513, Model 3 Res Holder

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    More power to you, ElSupreme! 60 kWh is indeed the sweet spot in so many ways, tangible or otherwise. I'm hacking away too at all those pesky recurring monthly expenses that I get so little out of.
     
  20. ElSupreme

    ElSupreme Model S 03182

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    The real problem is convincing my wife we don't need DirecTV. Before we started living together I got all my TV over the AIR! HDTV broadcast is really nice. And I generally only watch movies on HBO, and for $7 a month I can watch all the Netflix I desire.

    Although I will miss "Game of Thrones"! :scared:
     

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