This never happened to me before

[dwegmull]

In my experience, I can achieve parity between the two readings by driving at a constant 55MPH.
If I keep my energy consumption below that, the estimated range will be greater than the ideal range (by 5 to 10 miles). This happens on days when I drive only on local streets with 35MPH speed limits and few quick accelerations.
My regular commute includes a mix of highway (65MPH) and local roads, moderate changes of altitude and several traffic lights on roads with speeds around 50MPH. Under these conditions, my estimated range is shorter than ideal by 10 to 20 miles.

[TEG]

A little 'trick' someone recently told me:
At the start of a long trip, set the trip meter to 0.
Then watch the miles add up on the trip meter, as the estimated miles remaining goes down.
Add them together mentally and compare the trend of difference between that sum and the original projected miles when you started.
If you are quick with addition and comparison you can calculate on the fly how your driving style is affecting your range better than the vehicle's own guess.
You are also armed with additional knowledge about the type of terrain and driving conditions you are likely to encounter in the near future.

[wycolo]

A little 'trick' . . .

Isn't that more or less what the 'range est' meter (under the speedo) is trying to do? That is the only one I can see anyway: remove prescription sunglasses, lean foreward, try to focus. Given ~10 miles or so of normal driving, it seems to recalibrate and when you end your trip it is right in line with the TS guage.
--

[slcasner]

Yes, TEG, we've been using that technique for many years in the EV1, RAV4-EV and now the Roadster.