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Using EVTripplanner, how many buffer miles should I add between SCs?

Discussion in 'Model S: Battery & Charging' started by Hometheatremaven, Aug 29, 2014.

  1. Hometheatremaven

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    I'm driving from San Diego to SF, and then on to Portland. I will use evtripplanner.com to calculate RM and stop at all the SuperChargers on the way.
    But I don't want to overcharge as it takes too long.

    After calculating the route's RM between SCs using EVTripplanner, what formula between each SC is best for reasonable peace of mind?
    RM + 50 miles? RM + 25%? Some other formula?

    Thanks.
     
  2. Myke Hines

    Myke Hines Member

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    I've seen that anywhere from 125-150% is a good estimate.
     
  3. Rlsarch

    Rlsarch Member

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    Just completed my first long distance this past weekend. my experience is that you will need to add +60 miles to target location. My trip was Orlando to Tallahassee cruise set to plus 70 mph. I found that managing the delta between my avg projected miles on the energy screen and distance left to target was a good gauge as to how well I was doing. example I started the trip with 155 miles to the Lake City supercharger and had 260 miles available, delta of 105 miles. Then i hit a very bad thunderstorm in Ocala and immediatly my delta was only 35 miles. after the storm cleared up it started to creap back up. I reached the target with 45 miles of avg project range left. So, in effect spent 215 miles of energy. Next leg of the trip was 95 miles and spent 150 miles of energy. Conditions really effect the effeciency so good to track the avg projected range. Return was about the same 50 - 60 miles of additonal range needed.
     
  4. Hometheatremaven

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    Thank you. I prefer to use EVTripplanner rather than my energy screen, as the website takes altitude etc into consideration.
     
  5. detlefo

    detlefo Member

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    I have driven from California to New Jersey and to British Columbia. I used EVTripplanner and found it extremely useful. My objective was to limit charging time so I always tried to arrive at the next SC with around 30 miles left. This provided peace of mind for unexpected detours or getting slightly lost. Of course, at meal stops I charged for the duration of the stop.
     
  6. Rlsarch

    Rlsarch Member

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    Good start yes, but does not give you changing conditions during the actual drive. For me, in Florida, that thunderstorm really changed the outcome. i would hate to have calculated it that close then hit a wind storm and not make the target all together??
     
  7. wraithnot

    wraithnot Model S VIN #5785

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    I usually shoot for a buffer of 25-30 miles over my best estimate of how much energy it will actually take and then keep track of things along the way and adjust as needed. On a recent trip from the SF bay area to Seattle, I found EVTripplanner with a 1.05 speed factor to be pretty close given how I drive, but your mileage may vary. The first road trip I took to the Pacific Northwest I was going to Portland and I forgot to add the buffer when figuring out how much range I needed at the Grants Pass supercharger. About 50 miles away from Eugene I realized things were going to be tight so I put the car in range mode and followed a nice slow moving truck the rest of the way. I pulled into the supercharger with 7 miles left and managed to keep my wife and our friend from realizing how close I was cutting it until we were just about to the supercharger. A missed freeway exit can cause real problems if you cut things too close.
     
  8. ZBB

    ZBB Emperor

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    #8 ZBB, Aug 29, 2014
    Last edited: Aug 30, 2014
    We did a 4,256 mile road trip this summer. EVTripper did a great job estimating -- in most cases coming in +/- 2 RM for each leg.

    As others have said, weather can get you in trouble. We had very strong head winds on one leg of the trip -- I ended up quasi-drafting a Semi at 60mph for about 25 miles, instead of driving the planned 75-77 (I planned at 1.1 speed factor) -- and still ended up within a couple RM of what EVTripper estimated (so had I driven at plan, it would have been a huge difference). We had another leg with light rain, and a couple legs with heavy tail winds too.

    For my planning, I did the following:
    1) Planned at 1.1 speed factor. That should be 10% over the limit. Most of the driving was at 5 over the limit (so not quite 10% over the limit)
    3) Added a 35 RM buffer for each supercharger leg.

    That ended up working really well. Most of the time, we ended up letting the car charge a bit longer than planned (since we were busy eating, enjoying a break or something...) -- so we usually left with more than a 35 RM buffer. The lowest RM we arrived at a Supercharger with was 28. Most were between 40-50 RM.

    Looking back on it, we could have cut 10-15 minutes out of all but a couple of Supercharger stops. But then again, only a couple of those were us waiting for the car, so will plan about the same for the next trip...
     
  9. Hometheatremaven

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    Thanks so much to everyone for your responses.
     
  10. invisik

    invisik Member

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    Yes in good weather conditions evtripplanner is spot on. I drove from Minneapolis to Nashville this summer and my rated miles exactly matched the physical distance at most stops. I usually charged an extra 50 miles for buffer. I even made an unplanned detour to the airport to pick up an associate and still had tons of miles left over.

    I admit I have not yet driven in bad weather... The estimations are excellent for good weather.

    -m
     
  11. Owner

    Owner Active Member

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    I have found EVtripplanner to be in general very accurate as long as you plug in the correct weather. A few cases where it was off seemed to have more to do with elevation changes. But in general it is a great guideline and I typically have a 10% buffer. Only experience driving really lets you get there with say 0 miles left in the "tank".
     
  12. jacobp

    jacobp Member

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    Here is my rule of thumb and I've never had even a hint of trouble: 150% of actual miles plus 25 miles.
     
  13. brianman

    brianman Burrito Founder

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    This (too high) kind of buffer would make many of the legs of my trips impossible. Then again, I've been told I'm bold, crazy, eccentric, "not normal", etc.
     
  14. Lawsteve

    Lawsteve MCATDT

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    I tried evtripplaaner for the first time before my Tampa to Panama City FL trip this weekend. It must still be a little rusty regarding the Lake City supercharger. Rather than routing me directly west on the 210 mile route from Lake City to Panama City, it sent me north to the Tifton, GA supercharger, and then southwest 198 miles to Panama City. Probably would have added at least 150 miles to the drive.

    Of course, it is quite possible I did something wrong on the settings for the site, but I didn't waste much time trying to figure it out.

    I decided to fiirgure out the trip myself. Made the direct route with about 40 miles to spare. I did hit a pretty strong thunderstorm on the way and watched my efficiency drop off tremendously. Fortunately we were only in the storm for about 20 minutes. A 45 minute storm would have made the arrival a little exciting.
     
  15. wycolo

    wycolo Active Member

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    Or 'the MAX', whichever comes first. :wink:
    --
     
  16. ZBB

    ZBB Emperor

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    Sounds like you used the "route through superchargers" button. That feature was added while I was doing the planning of our trip a few months ago -- so I got used to not using it. Instead, I mostly plan the route manually and use the "direct routing" button -- that would have avoided taking you through Tifton GA...
     
  17. jkliu47

    jkliu47 Member

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    In my most recent trip (2050 miles) from LA to Santa Fe and returning via Las Vegas, I beat evtripper's calculated average 391 Wh/mi by more than 15% (328 Wh/mi). Maybe its because I was in Range Mode, used CC or unintentionally drafted trucks by keeping with flow of traffic and staying in right lane most of the time. I also encountered only 2 short rainstorms and probably benefited from almost no headwinds on the trip.

    Nevertheless I still charged to at least 50 miles more than evtripper's RM estimate for each leg of the trip - more for peace of mind of my wife than anything. I will definitely use evtripper in future trips, with perhaps less buffer miles.
     
  18. jacobp

    jacobp Member

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    Exactly.
     
  19. joefee

    joefee Over 2 Million TMC page views

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    We just did a trip CA-CO: add 50 extra miles & take a hard copy route map if your going through internet dead zones, get your tires/wipers/breaks checked as part of a safety inspection (free at SC)....have fun!
     
  20. DennisLevitt

    DennisLevitt Member

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    I've taken several road trips, including California to Connecticut. I agree with @detlefo. I found EVTripPlanner.com to be very accurate and very useful. It takes into account distance, speed, elevation, cabin temperature, external temperature and payload. Obviously bad weather is a factor, and EVTripPlanner doesn't account for that. But San Diego to Portland shouldn't be an issue. Given all that, a 30 mile buffer is plenty IMHO.
     

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