Commuter Booster - Analog Throttle Trial

[adrian_sm]

Since I made the Commuter Booster / Brain Box with only a push button a number of people have hassled me about implementing an analog/twist throttle. Personally I much prefer the push button, but I have coded up a version of the firmware that can use a normal hall sensor throttle, so if people are that adamant they want to try it out on their drive, let me know.

If you want to know more read below

- Adrian

-------------------------------------------

[Note: all power levels mentioned below are battery side power, not output power]

Currently brain box which performs all the throttle duties uses a momentary button as the throttle, with three throttle mode
1) Power Level 1 - [Simple press and hold of button]
- motor speed is ramped up and a PID loop is used to maintain that power level
- typically set at 500w

2) Cruise Control - [Quick release and press again]
- this uses a PID loop to maintain the current speed, while still enforcing the Power Level 1 limit

3) Turbo Mode - [Two quick release and press again in succession]
- Same as one but a higher power limit
- typically set at 1000w

The v0.8c firmware now turns off the digital throttle, and only accepts the analog throttle.
- I have hard coded a minimum 200w power on the low end to help maintain the drive engagement
- Power1 in the settings is used for the upper end of the throttle range
- then the throttle position determines what the target power is between these two limits

I tested it at 500w (the power level I normal use the drive at) and found it pointless. I ended up using full throttle all the time.

Then bumped it up to 1000w and you start to get some modulation you feel you can use. But still found myself normally just pegging it at full throttle.
I came back from the test ride not liking it and really not wanting to waste my time on it further. This may be partly be due to the slow ramp up times I have by default via the PID parameters. These were deliberately set to smooth the engagement for the digital throttle, but not ideal for the feel of an analog throttle. Of course you can tweak the PID parameters via the settings menu, so feel free to try and optimise it yourself.

I have currently set the throttle up in a POWER PID mode. Normally the throttle on a typical ebiek controller actually sets the PWM to the motor which is only over-riden to enforce the current limits. I can do this too by changing a few lines of code, so hassle me if you think this would be better.

Soooooo .... if you feel like cracking open you Brain Box, soldering in a hall throttle and giving it a go, let me know and I'll shot you the instructions and files to flash the new firmware. You can always reflash to the old once you have finished playing.

- Adrian

P.S. Oh this version of firmware also supports adjusting the settings via your computer terminal screen, rather than button presses and the LCD display on the unit. This was mainly to support a setup that has no display attached.

 

[-dg]

Ok, silly question, but your comment about using full throttle most of the time has me wondering if on lower power bikes if there any need for a throttle at all. It seems to me that an on/off button would be enough control, with maybe some limit on ramp-up speed if you want to be fancy? Or is this impractical for some reason?

 

[adrian_sm]

Exactly what I do. Power limit, with ramp up and down control.
Works a treat. It won't suit everyone, but at lower power limits I find it great.

The cruise control and second power limit are just icing on the cake.

Having said that when rising in a pack of other bikes you may want more control. Hence the request for an analog throttle I guess.

 

[Glenn_M]

The riding in a pack comment is spot on. That's what I was thinking on Sat trying to control the speed with simple on/off (and pedaling) in the group. Hence my question about more throttle control.
However, also had forgotten about the cruise control option.
Think I'll just learn to the use the unit as-is atm before making changes.
Cheers,

Glenn

 

[adrian_sm]

I found myself just pedalling a lot of the time when I used the Commuter Booster in the previous group ebike rides. Being on a easy rolling road bike against predominently lower powered and heavier ebikes made it easy to keep pace. Then I just laid on the power to have some fun, catch-up with the high power bikes, or tackle the hills.

I use the cruise control most when going through school zones or shopping strips with lower speed limits. When on the open road I just keep it at power 1, and pedal as much as a I like.

For group ride situations I would probably just set the first power limit a bit lower, say 300w, and the second up around 1000w. As 500w tends to catch people when I am on the road bike. All depends on who you are riding with.

I would be interested to hear how much people use the cruise control function. If they are not using it, I could instead implement 3 power levels.

If people have other ideas., feel free to throw them out there.