Paul & Sabrina's cheap DIY 144v motor controller

[esoneson]

Congrats Paul, Do you want your stick of Beaman's Gum now?

Your maiden voyage was successful and you survived, what more could you ask for?

I know that those little mosfetties wouldn't let you down.

Now take a little time to think about your next adjustments and don't forget to record your changes.

Thanks for taking the risk.

Eric

[Intrigued]

Hooray! Major milestone!!!

I knew our mosfets wouldn't let you down. Just a little more training, and they'll be slinging around electrons like nobody's business!!!

[MPaulHolmes]

I'm reprogramming it right now. It is sort of sobering now, knowing what I type can cause property damage! hahaha!

[Intrigued]

Dude, you are like the Master of Your Domain;

All Powerful;

the Ruler of the Universe!!!


...was that lightning???

[MPaulHolmes]

Much smoother!!!! ya!!!! Before you could hear a faint sound in the motor from noise because of sloppy A/D conversions. I slowed down the Analog to digital converter sampling rate, and I lowered the delay when the hardware shuts down the circuit. Now I can drive up the driveway at very low RPM.

I decided to floor it down the street!!! hahaha! The car accelerated VERY well, and then the current just held pinned at the current limit. You can hear a faint sound when the hardware current limiting kicks in! It's so fun!

I wish I could feel this at a higher voltage.

Video coming soon!!! ya!!! Controller #2 will be super easy to make! ya!!!!!!!!!

[bennelson]

Originally Posted by MPaulHolmes

I wish I could feel this at a higher voltage.

Mwaha ha ah ahh ha ha ha!!!!.

If I e-mail you an e-moticon, will that be good enough?

If I test drive at 144V for you, I promise to create a mad scientist multicam video shoot.

Just think of how many video cameras I could strap to the car!!!


Hey guys, anyone got a laptop we could send to Paul? I remember programming my motorcycle's controller through my spare bedroom window with a COM extension cable!!!

Paul, what connection do you need for programming? COM? USB?

-Ben

[MPaulHolmes]

Hey Ben! That was a really evil laugh. It goes well with that crazy mad scientist look you get sometimes.

It's a serial plug. I don't know the name. It's on the back of most computers and it looks sort of like the plug to the monitor. Is that a COM plug? It's definitely not USB.

I'm going to put that caulking stuff around the edges of the box to make sure everything is sealed. It would be nice if air could flow, but I think the heat sink is going to be good enough for that. After like 5 minutes of pretty hard driving up hills and stuff, the copper heat spreader was barely above the surrounding temperature (I felt it). Ian has had some problems with his controller getting hot, but the copper heat spreader and the more efficient mosfets seem to help a lot. I still haven't given it any real hard test, since it would make me really sad if it broke on the first day.

[esoneson]

So Paul, what did you limit the amps to in the controller during your wild ride?

Eric

[MPaulHolmes]

That's a good question! It is less than or equal to 500 MOTOR amps, but the exact amount is a bit tricky to figure. I have a homemade ammeter whose accuracy remains unknown to me. Plus, it measures battery amps, which is different from motor amps.

In fact,

Ibatt = Imotor*PWM_DUTY (or close to it).

Hey! I could use that formula! haha, but I'm never really sure what the PWM duty is while driving.

I know for sure that the hardware shuts off the mosfets each time the naughty 500 amp like is crossed. Right now I wait until motor amps drops below 500, then wait 1 PWM period, then turn them back on. I have no idea how much the current decays in that time. So, I would guess that the current limiting is something slightly less than 500 amps. hehe, sorry for the vague answer. The acceleration feels stronger than the 400 amp controller, so I would guess that it's more than 400 amps.

The battery amps read about 320.

[MPaulHolmes]

We got a video put together of the first weenie test drive (like 5 mph) and the more robust 2nd test. The 2nd test is first, since the first test was really boring. haha! I made sure the windows were open, since I sort of expected things to catch on fire in the car, and for me to die. I was pretty scared. I had to take 2 advil afterwards, because of my near death experience stress headache. hehe.

I'll be attaching the stupid video any second now, if it would ever stop uploading! Geeze! Hurry up! It's late! So anyway, while I wait:

What do you use hippie paper for?
Write on, man...

There are 3 to's in the English Language.
There are 3 two's in the English Language.
There are 3 too's in the English Language.
Which one do I use?
There are 4 twoo's in the english language! haha!

Do-dee-doo-dee-dooo.... Still waiting for it to finish! man...

So, future plans:
Improve the process, carefully document each step of that process, and put it together in some sort of master directions book thing, with sources for parts, techniques for soldering, etc.... With pictures of every tiny step.

It was incredibly tedious to make this work. You really need attention to detail, but I think that with really really good, thorough directions, anyone can make one!

Youtube makes me mad. It's taking a really long time.

How do you catch a bear?
Dig a whole, put peas all around it, and fill the hole with ashes.
So, when the bear comes to take a pea, you kick him in the ash hole.

That actually works, by the way.

EDIT: It's still uploading! I had a copyright issue because of a song I had at the end, so youtube muted it. I removed the video and am re-uploading it! I'll attach it as soon as it's done uploading. grr...

Hmm... It's 4:50am! Man, what am I a Dairy Farmer?
Here's an interesting story while I wait:

My wife and I lived in Kenya for 6 months trying to adopt a boy from Mother Teresa's in Nairobi. He was born like 3-4 months premature, and was found on the street right after birth. The police brought him to Mother Teresa's, and one of the sisters there and she was able to get an IV into his tiny veins. Then she gave him oxygen for a long time. Anyway, Kenya changed their adoption laws, saying we couldn't adopt a "pre-identified" child, meaning Mother Teresa's couldn't choose which orphan was adopted. It was the job of the "adoption committee", some moronic Kenyan government organization that was newly created. So we sent him back to Mother Teresas after 6 months and came home. The end! I love governments. Always looking out for orphans.

http://www.youtube.com/watch?v=OGhNXSk6BEw

There are a few editing issues. I didn't watch it before uploading it, but you get the idea. hehe.