What is the most efficient travel speed?

What is the most efficient travel speed?

For us Europeans there is always a big question when we go on road trips and have to crosse Germany. Do we have fun on the Autobahn and drive fast, but charge more? Or is it less time consuming to drive slower and charge less? This week I took it to the test and compared driving 120 kph to 150-ish kph (wanted to do 160kph, but traffic was too heavy to allow for that)

Even though driving faster is consuming more, you don't need to charge that much longer due to lower SOC with high kW rate. Of course, the equation doesn't really add up anymore when you intend to drive 200kph for a longer time. At some point, consumption becomes too high and charging times too long.

seanreynoldscs | December 29, 2018

Okay from yesterday: with a heater I was getting 400Wh/m at 80mph and about 325Wh/m at 65mph for a difference of 75Wh/m. The charge rate for the bottom half of the battery is 114kW each hour.

So if you just plug in a 1000 mile trip to make the math easy you get about an extra 40 min of charging time over the 1000 mile trip but your drive time goes from 15.38 hours down to 12.5 hours confirming what bighorn said.

So... I’ll be going 80 the whole way back.

jjgunn | December 29, 2018

Eff it....use the juice! Drive 80 cuz it's fun! Just be near a SuperCharger when you're at 20% or less.

p.c.mcavoy | December 29, 2018

In the end, it will all depend on the exact trip and route you are traveling, especially in cases where superchargers are not right off the motorway and you end up needing to divert further. For specific routes one can always use a tool like evtripplanner and start playing with the speed factor to look at the impact on total trip time.

It also of course depends upon your tolerance (or luck) for the added time delay while you are stopped waiting for the local law enforcement officer to run your plates/registration and determine what ‘gift’ you’ve won as the speed for shortest trip time in many parts of the US likely puts you faster than the posted speed limit.

seanreynoldscs | December 29, 2018

Yeah why do we have speed limits anyway? Wasn’t it due to an oil shortage in the 70’s? I find it hard to believe that my Tesla at 100 is any more dangerous than a motorcycle or simitruck at 70...

So I’ll try 90 on the way home and post my results.

I have a radar detector so that we can give sweet smiles and nice waves to the camping officers out there in the arena. :)