Paul & Sabrina's cheap DIY 144v motor controller

[squiggles]

Originally Posted by MPaulHolmes

Go Adam, it's your birthday, light a candle, throw a party! Adam's going to test the voltage limits. I'm really excited. He has 24 12v SlA batteries for testing. Ya!

Beautiful pictures! I have got to get a program like that! I want water coolign too!!!!! not fair!

Google Sketchup, just found out about it a week or so back. Download for free and be 3D modeling in minutes. Loads of video tutorials and all, it is a real hoot.

[adamj12b]

Ok, I ran into a problem with testing to find out how high of voltage the components can go. The problem??...I dont have anything that can put a sufficient load on the components. Dose anybody have something I might be able to use or an idea of something to come up with? I dont have the cash right now for much, so the cheeper the better. I was thinking of a forklift pump motor or something comparable that could draw about 100A under a load. I was also thinking of some large stove heating elements, but I dont think I have enough for that idea to work. What do you guys think?


-Adam

[fritzgutten]

adam-
are you worried about the inductive load and all that jazz? or just seeing what power it can handle?
if so you just need something with more resistance than a dead short right?
how about a bucket of saltwater and a anode cathode setup? i really have no clue....but its an idea...oh yeah, if you do that, do it outside and NO SPARKS!

[adamj12b]

Yes, inductive load is very important. It needs to be just like its in a car.

-Adam

[MPaulHolmes]

Joe's controller had been going from 0 to 80 amps instantly, and then smoothly from 80 amps on up. I finally figured out what was going on! Ya! Long story short, it's easy to fix. In fact, I don't need a new coupler! The banging I kept feeling was the immediate transition to 80 amps. I just never had a motor current monitor, so I didn't know what it was.

Now I think we need some sort of filter on one end of the controller, and then a fan on the other end, and that will keep the air moving, to extend Joe's controller's life. Maybe the material in a car air filter?

[jyanof]

Originally Posted by MPaulHolmes

Joe's controller had been going from 0 to 80 amps instantly, and then smoothly from 80 amps on up. I finally figured out what was going on! Ya! Long story short, it's easy to fix. In fact, I don't need a new coupler! The banging I kept feeling was the immediate transition to 80 amps. I just never had a motor current monitor, so I didn't know what it was.

I tried out the code with the extra line in it, and wow what a difference!

the car is a lot smoother from a stop now and the throttle control actually feels a little better. I guess when you consider that before we gained almost another 20% usable range of throttle, it's quite a difference.

The motor amps can be controlled down into the single digits and I set the max throttlePos to 470. This actually correlates to an output of 487amps (according to the meter i have, anyway) and doesn't trip the overcurrent protection. When I was playing around with it before, 490 amps started to trip the overcurrent protection.

Good work Paul!

[MPaulHolmes]

Oh, I'm so embarrassed! hahaha!

[dlaing]

Originally Posted by adamj12b

Yes, inductive load is very important. It needs to be just like its in a car.

-Adam

You could pick up a coil of wire from a hardware store, attach all three conductors in parallel, add a resistive heater in series, and you have a good simulator of an electric motor. I did a really rough calculation on this coil and got 1mH, but it isn't well wrapped, so say 1/100 of that, so 10uH. I wouldn't put more that 45Amps through the 3 wires without a fire extinguisher nearby.

[jyanof]

Originally Posted by dlaing

I wouldn't put more that 45Amps through the 3 wires without a fire extinguisher nearby.

I've read about people submersing their test inductor and resistor in a bucket of water. Keeps them cool enough to withstand brief tests of high current. Might work better with wires that aren't plastic insulated...

I actually tried this on a smaller scale when testing my charger. I have a heating element out of a space heater and couldn't get up to 20A without it glowing red hot. Tossed it in a bowl of water and no problems, though the water turned a funky green color, so I didn't do it again.

[Royal]

I am trying to set up Paul's AVR program on VMLAB simulation software. As I am not good at programming I need a good copy of a VMLAB project file for Paul's software. If anyone has set this up on VMLAB please help me with this. Royal