Paul & Sabrina's cheap DIY 144v motor controller

[MPaulHolmes]

Hi Alvin! Alvin's settings are the old code. t-rr is 6. Kp = 8, Ki = 1 I think. I think Alvin's code actually has the same bug that Hondos has. If the throttle gets too much noise on it, then the software shuts down the code because it assumes that it has a bad throttle. So, Alvin, if you ever want the reprogrammable one, just let me know and I'll mail you a chip. But if you are happy with it, then that's fine too. It's no big deal though. Either way.

[apowers]

Hi Paul. I'm satisfied with the smoothness but I want a little more pep. I have been busy
with other gremlins like voltage sag(fixed that) charger problems not fully charging
I think I have fixed that. I am just putting miles on it now to get more cycles on the batteries. I been riding around keeping the amps down about 50. When I bought the componants I bought a couple of extra atmega8's. I downloaded the avr studio. And the RTD explorer. I have not figured out how to use any of it. The compiler takes to long to download on dial-up(thats all thats available here) so I may not be able to do anything with it. Also I got the base plate from the same place as the heat spreader. The heat sink came from Heatsinks USA.
Thanks
Alvin

[MPaulHolmes]

Hi Alvin! You are having the same problem with acceleration as Hondo is having. I'll program a microcontroller and mail it to you in the next few days. Then you can use the RTD explorer and change the chip settings to how you like it. You will have to give the pot that's on the control board a bit of a turn clockwise. I think about 60/300 of it's total range of motion should do it.

[NiHaoMike]

By the way, this is page 255, which means we are almost out of byte territory! We can do it! Come on 256 = 0b100000000

To be pedantic, since the numbering starts at 1, you're not going to exceed the byte addressing limit until page 257. Unless you map 0x00 to a dummy page 0 instead of page 1, that is.

[MPaulHolmes]

Dang it! Mike is right! Makes me mad...

[esoneson]

Ok, usually I stay out of these things, but.......
A single 8-bit byte can store values from 0 though 255 ( 256 different values).
Any offset (i.e. definition of boundaries) of that single 8-bit byte requires additional space.
I.e. another offset value stored somewhere.
So.........0-255 is the range of values capable of being stored in a byte, unless, of course, the high bit is interpreted as a negative number, then you have 127 negative values, negative 0 and positive 0 and 127 positive values, which, when added up gets you 256 values.

8 bits is 8 bits, no more, no less. The program or the compiler may 'hide' the additional values, but parts is parts.

Eric (I promise I will never do this again)

Congrats Paul on such a long, interesting, and focused thread. Very useful to all.

[MPaulHolmes]

"focused-ish" hehe

[vpoppv]

Hi Paul! Here's the first of a million questions! ( I promise that I won't make you answer more than 999,999 after this one). I just got done watching your video again, and you said that "throttle is proportional to current and nothing else", how is it normally set up, like on a Curtis?

[MPaulHolmes]

On a curtis, throttle proportional to pwm duty. In other words, half throttle means half of the battery pack voltage goes to the motor. That causes jerky starts. Curtis did a little workaround for the jerky starts, though, but it does mean that they have to start at a lower frequency to be able to keep the high currents under control. They get the curtis whine (very annoying 1500kHz frequency) as a result.

Throttle proportional to current means half pedal = half of the maximum avalaible torque. Full throttle = maximum torque. So, if you take off from 0 rpm, it is VERY smooth, and you don't have to do any stupid stuff like the curtis whine.

[ianbartie]

There are hardware kits for the motor controller available here http://www.digitalhometech.net.au/in...roducts_id=193.
They have all the fiddly fixings, clips & stuff. They also have a very nice case with a machined heat sink & twin fans.