Paul & Sabrina's cheap DIY 144v motor controller

[taffy]

Hmm, I would be after some in the order of ....
1000Amps + but was going to settle for 500A. Hmm, i guess ill just go for broke first time round.

Naming:

100 Amp Little Miss Mosfet
200 Amp Oprah
500 Amp Cougar
750 Amp EV-1 (i think its owed something)
1000 Amp Delorean
2000 Amp "Going postal"... (Cause anyone going that fast is probably postal, were do i get 1?)

Group buy:
Not sure if Australia makes much sense there, we will see. Will price up what i can get here.

Donations:
$20 from me. How much do u need to build an entire controller, it was around $400 wasnt it?

What i am making: Drydanol - electric in welsh
Taffy's 2009 Locost

Photo's of build: I have been collecting the photos over this thread with an idea of trying to put together the construction process.

[MPaulHolmes]

That is going to be awesome Taffy!!! You won't have to search all over to piece it together. We're going to make it as easy as possible. The next build will have detailed pictures of each step. It will get better after that, because some people that know WAY more than me are helping me, but I'm sure this version will work really well. Also, the full parts list, and where to buy will be available too. There should be no searching involved. If we can get a group buy, I feel confident that it will be way less than $400! Maybe closer to $300, but I'll add it all up and see. Then we can estimate what a group buy would cost.

Right now,

[GrahamMc]

Taffy-

Hey. I noticed that you had a brushless DC motor on your list of parts. I do not think these motor controllers will work for one of those, but you will need to ask the others here to be certain that is true. I seem to remember this coming up and being informed that they only work for brushed dc motors.

[taffy]

Woops, i really should pay more attention to what box's i picked. No the motor is a series wound brushed DC motor, Warp 9. Which is a 32.3HP continuous and is happy to take 144V @ 190Amps all day long .

Thanks for picking that one up and please done give me heart failure like that in the future!

[bennelson]

A Warp9 with a 144V Open Source controller would be a really good combination.

A homebuilt controller would shave off around $1500 from the cost of that!

[esoneson]

Amen, Ben, amen.

Eric

[edown]

Hi, I’m Evan and have been “lurking” for about a week.. I’m converting a 92 Eagle Talon. I have a 96v, 30 HP motor from Ebay installed and have tested it with a 48V 300A Curtis.. I too decided to build my own controller and have a pile of blown IGBTs and Mostets to prove it! I wish I had found this string a month ago..
Anyway, I have a question.. Paul uses 24, 200v, 470mf caps. Is it OK to use 3 large, 4400mf 300v caps? Is it the total “mf” that is important?
I want to just screw mount 3 of them straight to the buss bars omitting the PC board.. I can get 10 of them for $30 on ebay right now..

[MPaulHolmes]

It depends a lot on the capacitors. You need a low Equivalent series resistance, so they don't dissipate too much heat with all the switching. People usually use lots of them because a bunch in parallel means the overall ESR is (in my case) 1/24*ESR_EACH.

You can try some large caps, but if they won't work, you'll know pretty quick. They'll get really hot. Try it! See what happens! It might be OK?

[MPaulHolmes]

I've got lots of progress to report on the control board and the driver board. I also ordered the part (I ordered 3 actually! ya!) that will allow for powering the contactor from inside the controller! I had one idea how to do this, and my little guardian angel emailed me showing me a really really awesome way to do it! The micro-controller now decides when the contactor shall turn on and off!

Like in "War Games", we took the human out of the loop!

QUOTE THE GENERAL: Gentlemen, we've been having men down in them silos since before any of you were watching howdee doodee! I don't know about you, but I sleep pretty well knowing those boys are down there!


Hmm... How about the pre-charge resistor? Heck! Let's take that part over too! Maybe we should even have the dang pre-charge resistor inside the controller? I don't know! That would be cool! That would cut down on wires to plug into the controller. Less human error.

You turn the car on and go! You turn the car off, and it's off! I like it!

I ordered some TINNIT Bright Tin Plate stuff. It puts a tin plating on copper! Now our copper bus bars can be nice and tinned and shiny! immune to corrosion!

Hmm... I've been working on the layout for the mosfet driver board (well, the "board" is only 0.8"x8" haha!). I'm going to have to surface mount the "through hole" parts. just a few. NO biggie! Then, the mosfet driver board is going to communicate with the control board by LIGHT! No electrical interference will be able to pass through! OPTO-ISOLATION! It's so dang awesome, I can hardly stand it!

I also am adding a zener diode (I never knew what those really were until today. Don't tell anyone! It's a secret. I'm the "expert" hahahaha!) to not allow voltage spikes from gate to source. It will clamp the voltage from gate to source to no more than 20v. The voltage from gate to source can now freely rise to 20v, and then all of a sudden, BAM! NO MORE! HAHA! If even a small voltage spike of 30v hits the gate, it can destroy the mosfet. That could have been what happened last time. Now, that potential problem is eliminated!

I'm dramatically improving the ground connection between the mosfet driver and the power section. wire with LOTS of surface area. The control section will have it's own nice peaceful ground. That is going to dramatically smooth out the signals, like from the current sensor!

I hope those crystals from china get here soon, so I can run that sucker at 16 MHz.

Note: The improvements have all come from not me! haha! I love open source!

[GrahamMc]

Paul-

By light? Do you mean fiber optics? Maybe we should crowd-source contracts to NASA because this thing is getting pretty high tech. Are you still in the $300 price range?