View Full Version : elmoto-ish alltrax settings

12 August 2013, 1325
What might be "typical" starting settings for programming an alltrax (AXE 7245):

1. throttle up rate (default's 5)
2. throttle down rate (default's 5)
3. throttle curve (default's "custom" is parabolic...close to "progressive").

Interesting that "linear" isn't, well, linear.

Riding style will mostly be a combination of commuting and potential dual-sport off-road (dirt roads with some potentially steep grades). Max speed ~65mph.

Thanks much!

12 August 2013, 1647
I have a true linear curve if you want it.

I actually found a way to make my own custom curves. The custom curves are hex files for a PIC microcontroller. I used to program PICs, so I had some old software still on my computer. One of them contains a disassembler. By disassembling the hex file, I found that it contains a simple lookup table (a few instructions followed by 256 "retlw"-instructions). I made an excel sheet which generates all retlw instructions. I then used it to create the source for a linear curve, which I compiled and put into the Alltrax. And it worked!

I had the idea to make a "piggyback" controller, which would create a true "torque throttle" by reading the motor current through the serial port of the Alltrax (or an external sensor), as well as a throttle connected to the piggyback. It would then apply a signal to the throttle input, which would create the desired torque.

If you connect a light bulb or similar to the output of the controller, you can visually see the difference when you play with the different throttle rates. But it's probably more useful to test it on the bike. You may start with both at 1, and then increase from there until it's quick enough. When they are set at 1, it takes several seconds for the speed to ramp up.

12 August 2013, 1850
I have a true linear curve if you want it....I actually found a way to make my own custom curves.

Thanks for your generous offer bjn. And, nice sleuthing on the curve's lookup table. I guess if it has to be in a hex file, the RETLWs make sense.

I was just looking for quick/dirty throttle values people have tested in their bikes. For now, I have throttleUp=6 and throttleDown=12. The parabolic "custom" curve should be fine for now. If I find I can't get what I need from the up/down rate settings, then I might consider the curve down the road.

Also, interesting torque throttle concept. I read somewhere in the Alltrax docs the current sampling sent to the log is +/- 10%. That inaccuracy could matter with large current draws.

In the meantime, I'll try these settings and see what happens (famous last words).