Vado 3 assistance query

[modelaero]

Hi - I have a Vado 3 and I use BLEvo. Since I bought it, I have had peak power set to 100% on all three modes and assistance levels (usually) of 15%, 50% and 75%. In the Trail and Turbo modes, I can feel the bike giving max power to assist but in the Eco mode, I never get the max power. If I analyse the .csv data from BLEvo, I can see the rider power vs the bike power and it never gives as much boost on Eco.
The graph below shows assistance off, eco, trail and turbo with the assistance highlighted in blue. The same short circuit is ridden four times with a short steep hill to generate max power from both bike and rider.
The rider power (grey) is the about same in all four modes (OFF, eco, trail and turbo) but the motor power (orange) just does not peak in the eco mode.

In the graph below, the same circuit is ridden with assistance set to OFF, 0%, 50% and 100% according to the dataset above. and peak power set to 100% on all three power modes. The results are almost identical. The effect does not seem to be related to assistance level. It seems that in Eco mode, the peak power is limited, despite requesting 100%.
Has anyone else seen, or suspected, this effect? Rider power = orange, bike power = blue.

 

[Stefan Mikes]

@modelaero:
I don't want to analyse the graphs but what I can understand is...

Specialized 1.2E (Brose C) motor data:

• Maximum assistance (max boost): 2.8x
• Maximum mechanical power: 420 W
• Maximum electrical power: 525 W (that's what BLEvo reports). (Estimated motor efficiency is 80%).

Case A
If you are in 15% assistance, the boost will be 0.15 * 2.8 = 0.42.
To get 420 W mechanical power, you need to input: 420 / 0.42 = 1000 W of leg power into the cranks. It is not doable for a human being.
If you input 400 W yourself, the motor will respond with 400 * 0.42 = 168 W (battery power draw = 168 / 0.8 = 210 W)

Case B
If you are in 50% assistance, the boost will be 0.5 * 2.8 = 1.4x.
You input 400 W, and you shall get 400 * 1.4 = 560 of mechanical motor power. It is infeasible, you get 420 W of motor mechanical assistance (525 W of electrical power draw).

Case C
Exactly as the Case B: You have maxed the motor out.

Now, it should be very clear for you why the Max Motor Power should also be limited: to differentiate between different Assistance Modes, and to conserve the battery charge for longer rides.

Case D
Assistance/Max Motor Power = 15/30%. Input 400 W. The motor is now capped at 0.3 * 420 W = 126 W. See Case A: Now, you will get 126 W of mechanical motor assistance instead of 168 W.

Case E
Assistance/Max Motor Power = 50/50%. Input 400 W. The motor is now capped at 0.5 * 420 W = 210 W. See Case B: Now, you will get 210 W of mechanical motor assistance instead of 420 W.

Case F
Assistance/Max Motor Power = 75/100%. The motor is now at full 420 W max mechanical power. Input 400 W. You should be assisted at 400 * 2.8 = 1120 W but the motor can only assist you with 420 W mechanical (the motor gets maxed out).

I hope this explanation is clear. As I can see your leg power is high, I recommend seriously reducing both Assistance Level and Max Motor Power to differentiate the boost and battery consumption between the modes.

Interestingly, you seem to be an ideal user for Specialized SL e-bikes that offer 1.8x max assistance and less than half of maximum power compared to your Vado 3.0!

 

[modelaero]

Thanks for the reply Stefan. Just a quick time limited response at the moment. Your maths are perfectly understandable and I will experiment further. What I still don’t get, is why in the second graph, when 0% power is set (as opposed to OFF) the motor still generates power.
More later…

 

[Stefan Mikes]

Thanks for the reply Stefan. Just a quick time limited response at the moment. Your maths are perfectly understandable and I will experiment further. What I still don’t get, is why in the second graph, when 0% power is set (as opposed to OFF) the motor still generates power.
More later…

No idea. I am "e-bikeless" at the moment, so I leave the matter to your experiments!

 

[Allan47.7339]

It could be an anomaly but it looks like you shifted power at the same point on both curves. There seem to be two peaks at the end of the run assuming the flat spot in the graph at 04:19 is the end of a run and about 3:20 on the second graph is the end of a second run? Marking the start and end of each run would be helpful and if you keep the colors consistent between the graphs it's easier to understand. I assume the left vertical axis is watts and the right is just integer power switch setting?

It is possible for amateurs to hit 1000 watts but usually only for a very few seconds.

 

[modelaero]

I've done some more study on this now and I think there are some problems with the Blevo app when it reports assistance levels, and therefore what it reports when it calculates the data. Bear in mind this is on a Vado 3, not one the bikes for which the app was written.
Below is the thumbnail graph of a recent ride, when the majority of the time, the assistance was either OFF or in ECO mode. The app reports that, after an initial time when the assistance is switched on, it never goes below ECO and briefly goes to TRAIL and TURBO modes. In fact, for a lot of the ride, the assistance was switched OFF. Rider power grey, motor power orange and assistance levels (on the right side, levels) 0,1,2&3 for OFF, ECO, TRAIL & TURBO.

Below, is the same power data with a logical analysis of the times when both rider power and motor power are present, representing times when the assistance is either ECO, TRAIL or TURBO (it is irrelevant which). There are many occasions where only biker power is being recorded, corresponding to when the assistance is OFF. This is at odds with the reported BLEvo data in the .csv file. I shall have to analyse the data further and perform some calculations to see how they stack up against Paolo's, but it may take me a while... Incidentally, the assistance level is shown as an arbitrary number 2.