Wednesday, December 10, 2014

Tesla update and trip planning

Just scheduled the installation of the electric charger in my garage, the day before Christmas, Wednesday Dec 24th.  Car was scheduled to be delivered about then, but I read about a delay on the line, so it may arrive later.

Reading an interesting thread on the Tesla board.  Trip planning with a Tesla is different than in a gas car for more reasons than I expected.  Yes, the first thing is to make sure you can recharge along your route.
  What's interesting is trying to minimize the amount of time on the road, or I should say, minimize time charging.  As with most rechargeable batteries, the charge rate is greatest when the battery is empty, with the speed being reduced as the battery gets filled.  To minimize your charging time you should be as close to empty as possible when you start charging.  Therefore, when you do charge, you want to only get enough miles to make the next charger, plus a small safety factor.
  There's also the question of speed: does the extra charging that's needed if you drive faster take longer or less time than you gained by driving faster.  The Tesla needs 14hp to go 65mph and 26hp to keep 85mph.  Going 85 gets you to the next charger 150 miles away, in 1 hour, 52 minutes, while at 65mph it would take you 2 hours 18 minutes.  With the 26 minutes saved, you need to charge roughly twice as much power.  If it would take 30 minutes to charge enough for the next 150 mile stretch for the 65mph car, would it take 56 minutes to do the same with the 85mph car?
  The followup question would be about skipping a charger.  Going west from Denver, there's a charger in Silverthorne, Glenwood Springs, and Grand Junction.  Then Green River, UT.

  90 miles from Silverthorne to Glenwood Springs
  86 miles from Glenwood Springs to Grand Junction
101 miles from Grand Junction to Green River, UT

Knowing I need to recharge in Green River, UT, would it be faster to charge at all four or faster to skip one?  Looking at the route Tesla took in their cross country ride this past winter, it looks like they stopped at every charger they could.


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