One of the critical assumptions in EV TripPlanner is the Wh/RM of each vehicle; it is the foundation upon which all the other adjustments are made to determine power consumption for a trip. After running some scenarios, most of the models use 300 Wh/RM, which is also what Tesla tech support told me they use. But in looking at my own MS 90D w/19", I've concluded it uses 290 Wh/RM.
I arrived at this by evaluating this equation half a dozen times and always getting 288-290 Wh/RM:
30mi average Wh/mi / (Rated range / Projected range) = Wh / RM.
Of course the calculations can also be done in km and Wh/km and then converted to miles.
Applying the 290 Wh/RM to my 100% range of 292 yields a usable battery of 84.7 kWh which also seems about right (i.e., ~ 5 kWh battery reserve / buffer). By comparison my BMW i3 has a 3.2kWh reserve/buffer based on BMW's published numbers.
The values are all displayed as integers so we're going to get a little more variation in the Wh/RM than if we had one decimal of accuracy, but I suspect they are going to cluster pretty tightly.
I'm suggesting a three step process:
1) Some of the more critical readers need to verify that the above formula will yield the assumed Wh/RM. If that flunks, then game over.
2) If the formula is correct, we need a few owners of each model/wheel combination to do the math and determine the assumed Wh/RM for their car.
3) We compile the results and send it to Ben Hannel so he can update EVTP with the corrected numbers. Then we'll all have more accurate projects for our road trips.
Let's try step 1, does this make any sense?
I arrived at this by evaluating this equation half a dozen times and always getting 288-290 Wh/RM:
30mi average Wh/mi / (Rated range / Projected range) = Wh / RM.
Of course the calculations can also be done in km and Wh/km and then converted to miles.
Applying the 290 Wh/RM to my 100% range of 292 yields a usable battery of 84.7 kWh which also seems about right (i.e., ~ 5 kWh battery reserve / buffer). By comparison my BMW i3 has a 3.2kWh reserve/buffer based on BMW's published numbers.
The values are all displayed as integers so we're going to get a little more variation in the Wh/RM than if we had one decimal of accuracy, but I suspect they are going to cluster pretty tightly.
I'm suggesting a three step process:
1) Some of the more critical readers need to verify that the above formula will yield the assumed Wh/RM. If that flunks, then game over.
2) If the formula is correct, we need a few owners of each model/wheel combination to do the math and determine the assumed Wh/RM for their car.
3) We compile the results and send it to Ben Hannel so he can update EVTP with the corrected numbers. Then we'll all have more accurate projects for our road trips.
Let's try step 1, does this make any sense?