lorenfb wrote:Then not very useful, not having remaining Ahrs/kWhrs, i.e. only SOC and range are not helpful when you have a "shrinking gas tank". Hopefully, Jim (LeafSpy) will continue his efforts in providing a "TeslaSpy", if he hasn't
provided one yet. Even though future BEVs will have much less of an issue with range anxiety, it's still very
helpful to know the actual remaining (& @ 100% SOC) battery capacity either in Ahrs or energy in kWhrs
Tesla's rated miles (RM) serve as a proxy for usable capacity and are used as such by Tesla drivers. It is also a more user-friendly metric than kWh or Ah. Something I can say with confidence, having used it to stretch the range of my car on a recent road trip by comparing the RM to actual miles left and keeping an eye on how the difference varied with terrain and speed; it is straightforward and intuitive in a way that kWh and Ah would not be.
In my car one RM is 300 Wh/mile so if my accumulated trip energy usage has been 330 Wh/mile, something that Tesla displays on the dash, I know that I need 1.1 x as many RM left as actual distance left. If I fall short of that number I can slow down and reduce my energy usage. If the number of RM left is greater than 1.1 x actual distance left to go I can speed up, if I wish. In actual usage one can just compare the difference between RM left and actual miles left. If that number is shrinking one might be using energy too quickly to make the destination, depending on the size of the difference. The trip plot provides an even easier way to measure progress in fuel usage versus distance since it displays current SOC, projected battery SOC at the destination, compensates for terrain, and does the calculations automatically.
Where temperature, HVAC use, and the like come into play is in actual energy usage for the trip, something that is displayed on the dash in Wh/mile. Most of the time leaving on a trip leg with a sufficient buffer makes watching the numbers unnecessary. If I leave with 170 RM to make a 90 mile trip leg I certainly don't have to pay attention to energy usage under most driving conditions. It also is irrelevant for local driving since the range of the car greatly exceeds my local driving needs (70 mile grocery shopping trips with large elevation change, for example). But the energy in the battery information is there if needed.
I just got a headache. It's overly complex and still relies on historical averages. Even with my ICEVs,
I discount the range estimate and utilize the gas gauge. Using either Ahrs or kWhrs is analogous
to having a gas gauge which essentially is a true measure of capacity. Besides the typical consumer's
unfamiliarity understanding of those terms, most BEV OEMs don't care to have the consumer become
aware of battery degradation. Unfortunately, most all future BEVs won't ever provide a true measure
of remaining battery capacity.
With my monitoring of my Leaf over the last 3.5 yrs (47K miles), I can very reliably estimate my range
as a worse case estimate of about 2.2 miles/Ahr. Yes, my estimate is based on averages just like the Leaf's
GOM (poor), but at least I can see in real time how the actual capacity is changing and NOT relying on
historical longer term estimates. That's one of the reasons many of us utilize LeafSpy and/or LeafDD.
Furthermore, having access to the actual battery Ahrs, allows my determining
how low the battery
will be discharged during a current trip before a re-charge.
Leaf SL MY 9/13: 64K miles, 49 Ahrs, 5.1 miles/kWh (average), L2 charges to 100% > 1000, max battery temp < 95F, min discharge point > 20 Ahrs