2015 Turbo X, Maximum Speed?

[ferrellms]

Today I was able to cruise on the flats in full Turbo mode with the 691 Wh Turbo S battery on my 200W base Turbo. I was able to sustain at least 27 mph with assist still running. The cutout was just above 27 mph. I logged a mile in 2:16 which is 26.5 mph. Cadence was around 90 rpm. This is definitely faster than I could go (by maybe 1 or 1.5 mph) using the 468 Wh standard Turbo battery.

Hard to see how the battery could make a difference in top speed, given that the nominal voltage output is the same for all the Turbo batteries. I have tried the 3 different Turbo batteries in my Turbo X and haven't noticed any real difference. In each case, the assist stops at 26-27 mph. It is possible that there was a fuller charge in the new battery, which will increase output a bit until some discharge takes place. Or maybe you were a little more excited with the new battery!

http://www.bixmart.com/nominal-voltage-of-lithium-ion-batteries_ep_54-1.html

 

[jamesthewright]

I consistently can get up to 26.5 mph before the motor cuts off however if I am energetic I have gotten it up to 31 mph on a flat (shortly), 33 downhill!

Cheers!

 

[Douglas Ruby]

Hard to see how the battery could make a difference in top speed, given that the nominal voltage output is the same for all the Turbo batteries. I have tried the 3 different Turbo batteries in my Turbo X and haven't noticed any real difference. In each case, the assist stops at 26-27 mph. It is possible that there was a fuller charge in the new battery, which will increase output a bit until some discharge takes place. Or maybe you were a little more excited with the new battery!

http://www.bixmart.com/nominal-voltage-of-lithium-ion-batteries_ep_54-1.html

The issue is not battery voltage or the 691 Wh vs. 468 Wh. Here is what I believe is happening.

1. With both the 468 Wh and 691 Wh batteries, the speed cutoff is either 25 Km/h or 45 Km/h as set in the battery configuration. If set to 45 Km/h, the bikes with the 200/250W GoSwissDrive motors appear to shut down at 42 Km/h.
2. The controller in the battery is the key determinant, not the motor itself, for implementing the cutoff at the indicated speed.
3. Speed sensing is dependent on the wheel diameter setting also set in the battery. The higher the set diameter, the lower the rpm of the wheel at the cutoff.
4. With the bluetooth interface, I can modify the wheel diameter setting in the 691 Wh battery.
5. By setting the wheel diameter at 2150 to 2200 mm (which is less than the actual diameter), I was able to fool the controller into thinking I was going a bit slower than I actually was.
6. I think this effect (setting a smaller wheel diameter than actual) was what gave me .5 to 1 mph.

Note that the effect described above does not account directly for the difference in speed cutoff (42 km/h vs 45 km/h) between the 200/250 W motors and the 500 W motor in the Turbo X. BUT the battery controller knows that it is connected to a base Turbo motor instead of Turbo X motor, so there may be something there that affects the interaction. Also, with the 691 Wh battery, I was able to set Acceleration Response to "Race" which helps with the initial "punch" as you start accelerating. This makes the bike "feel" stronger with the 691Wh than the Normal setting that is the default with the 468 Wh battery.

It also may be that these settings (wheel diameter, top speed cutoff, and acceleration response) are used to "initialize" the motor when the bike powers up. If that is the case, then the actual cutoff is implemented inside the motor based on settings downloaded from the battery. This would account for the difference between the 200/250W motors and 500W motor and would explain why GoSwissDrive specs say that the lower power motor cuts off at 42 Km/h while the 500W motor cuts off at 45 Km/h.