Low battery warning not early enough

[TomT]

Intuitively, I would say yes, though I have nothing scientific to back up that statement nor any idea of just how much slower would be optimum...

If 38 mph is the sweet spot for a flat road, does that sweet spot become a lower speed as the grade increases?

 

[edatoakrun]

Intuitively, I would say yes, though I have nothing scientific to back up that statement nor any idea of just how much slower would be optimum...

If 38 mph is the sweet spot for a flat road, does that sweet spot become a lower speed as the grade increases?

Notice the chart has rpm and torque on the 2 axis's. Extreme torque and rpm conditions, both low and high, are less efficient, so optimum-range speed is probably quite a bit lower than 38 uphill, and higher than 38 downhill.

Using climate control (energy used is a function of drive time) will also increase the optimum-range speed, and higher drag conditions (windows open) will lower it.

The very broad 95% efficiency area in the middle of the graph probably reflects the experience we've all had, of getting consistently good range at speeds between 30-45 mph, as long as you can limit power use (no steep grades) to two "bubbles" or less.

 

[JRP3]

Some simple testing could be done, drive the same trip, a distance of a few miles at 38mph, 30mph and 20mph and see how many watt hours it takes to recharge the pack for each trip. Use a kill-a-watt meter if the car or charger doesn't give an accurate figure. Obviously you'd need a route that would allow you to easily hold those speeds or close to it.