Now, we will have an interesting subject for a while! I'm sure you Jeremy will find out yourself and tell us!
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I was trying to figure our how the ER was calculated based on my past use of BLEvo (which was able to calculate ER pretty accurately), the ER calculated by my Giant Trance E+ and by observing Smart Range on my Garmin Edge connected to the big Vado. My feeling is any Range calculation tool only looks at these parameters:
- Current remaining battery charge RBC (Wh)
- Current battery consumption factor BCFc (Wh/distance unit)
- Previous value of BCF, that is, BCFp
Anything else (your leg power, climbs/descents, wind and all other resistances, starts/stops) are all external factors affecting the three parameters above.
The Vado SL "brain" is calculating ER and RT all the time as you ride (regardless you have those parameters on your display or not). Meaning, the e-bike is constantly learning. The calculations are done frequently. (How often? I don't know! If you know anything about the numerical methods to calculate integrals, you also know the shorter the integration step the more accurate the calculation is).
Let's assume your last calculated BCFp was 4.60 Wh/mi (stored in the system memory). Your battery is freshly charged and the RBC is 320 Wh. The system has no idea of the external conditions when you turn the e-bike on. So, the ER = 320 Wh / 4.60 Wh/mi = 69 miles. Remember, it is just an
initial estimate. Let us assume you ride effortlessly with a tailwind on the flat in the ECO mode. The system can see that BCFc is lower than BCFp hence the Range Trend is
positive.
Now -- and it is very important -- the new BCFp is
an integral of the last BCFp and the newly measured BCFc! For instance, your new actual BCFc is constant and it is 3.90 Wh/mi. The value of BCFp changes: 4.60... 4.59... 4.58... and so on until it reaches 3.90, which might take a mile or so. But meanwhile the RBC dropped to 320 - 4.60 = 315.4 Wh, so ER = 315.4 / 3.90 = 80.87 mi. Estimated Range has increased over the mile!
I mentioned
integration done during the calculations. It is absolutely necessary! Fancy you go OFF. The BCFc = 0. If not the integration, your ER would
immediately become infinity! However, as the calculation uses integrals, your ER will slowly grow grow and grow, and it might eventually become
--- after the day spent only on pedal power. The same happens when you are coasting down the hill!
So you had an easy ride with the BCFp and BCFc stabilized at 3.90 Wh/mi. Now, you encounter a hill and pedal harder (forcing the motor to deliver more power and draw more from the battery). You might go SPORT or TURBO, Say the BCFc goes up to 9.0 Wh/mi. As BCFc - BCFp is positive, the Range Trend becomes negative! Now, the integrated value of BCFp goes up: 3.90...3.91...3.92...(...)...9.0. Now, let's say the RBC is only 270 Wh. Slowly, very slowly the ER will drop to 270 / 9.0 = 30 mi. Note: It was 80 before but it is now only 30 miles
estimated remaining range.
Obviously, as you coast while descending, and the BCFc = 0, integrating the BCFp will gradually increase ER.
Hit a headwind! The same happens: to maintain the speed, you need to use more motor power: negative RT and gradual decrease in ER.
What happens when you're slacking? If you keep
the same assistance then the ER will increase! Less leg power =
slower speed =
less resistance = less motor power demand = lower BCFc = positive RT = higher ER! However, go TURBO to increase the speed and the ER will drop off the cliff

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I absolutely don't know what is the battery minimum % for the Range calculation. I'm afraid it is 0%, as the designers seem not to think of anything outside the maths
P.S. Just some extra information: Range Trend is a differential while Estimated Range is an integral. Mathematics, Automation and Control!