Paul & Sabrina's cheap DIY 144v motor controller

[MPaulHolmes]

Originally Posted by GrahamMc

Yeah I think maybe some rigorous testing may be in order before the bulk purchase. I am really proud of you guys, you are restoring my faith in humanity.

Definitely rigorous testing first! Oh come on, now! Humanity is still sort of a spicy meataball...

[MPaulHolmes]

I got the 16.000 MHz quartz crystal oscillators in the mail from China today. I think there are 50 of them. You only need 1 per controller, so that's good. Now I can run that dang program at 16 MHz instead of 8 MHz. I tested programming the micro with the crystal hooked up, and I programed the chip to run at 16 MHz, and it seems to be working fine! I haven't tested it yet, because the control section is still not done.

Also, an interesting side note: When the AVR type of microcontroller's internal RC (resistor/capacitor) oscillator is used for the system clock, it's only accurate +/- 5%, but you need +/- 2% when attempting to transfer data back and forth through the serial port, which the controller now has (well, pretty much anyway. Not tested yet. hehe) The 16 MHz crystal provides that precision clock! ya! So, extra awesome!

Oh ya, if you are ever really hungry because you had the flu, and got better pretty much, and you have tons of jelly beans, don't eat all of them, because it will make you really sick again.

[eco_generator]

Originally Posted by MPaulHolmes

it will make you really sick

Yes, yes. I got really sick from the lack of sleep reading through this whole thread for the last couple of nights!

And for the people who says it's 70+ pages... you really need to adjust your settings in the User CP.

And oh yeah, excellent job so far!
(But I still might sue for damages from the lack of sleep...)

[edown]

Happy Happy, Joy Joy!! I finished my prototype power stage and it works GREAT... I used my last 50A mosfets (7 total) and 5 of the STTH6002 diodes with one 12,500mf cap… I put the car up on blocks and in 4th gear and ran it at 50 mph, 72 amps (48V) for about 6+ minutes and it barely got warm.. I took it up to about 105A.. I can’t believe how good the output square wave is.. And I was using just one mosfet driver... Also the single cap never got warm.. (It got very hot fast and blew out a 250 amp fuze when at first I had the cap in backwards, somehow the cap still works).. Notice I used no circuit board for mosfets, diodes or cap’s.. I plan to use the same format for my full scale version with 3 caps and my M- buss will be 1/4” copper soldered in to a (square tube) box for water cooling..
Question Paul: I want to use 3 or 4 mosfet drivers in my final version, should I couple the driver outputs or not? Or do you think the driver you use is OK to drive 12 mosfets?

Suggestion: I put an LED on the driver output for a visual aid.. It helps with trouble shooting and just lets you see things are working before turning on the main contactor..

I hope the pictures work..

<P><IMG src="http://edown.welldamn.net/ebay/controler1.jpg"> <P><IMG src="http://edown.welldamn.net/ebay/controler2.jpg"> <P><IMG src="http://edown.welldamn.net/ebay/controler3.jpg">

[edown]

HELP!
I can't get the pics to work

[eco_generator]

Here you go:

[edown]

[edown]

Thanks so much.

[MPaulHolmes]

That is awesome! Man! Those are some SQUARE square waves! ya! Way to go!! I love it! I would definitely say that cap can handle it! ha! YA!!!

Originally Posted by edown

Question Paul: I want to use 3 or 4 mosfet drivers in my final version, should I couple the driver outputs or not? Or do you think the driver you use is OK to drive 12 mosfets?

It depends on the mosfet driver and the gate resistor values. The IXDD414PI can put out 14 amps when it needs to, but my 10 mosfets with 30 Ohm gate resistors uses a peak of 4 amps, so you can do 12 mosfets on a single driver. The only thing to think about is how far away some of the mosfets get which delays their turn on times SLIGHTLY. I would suggest you use 1 driver for 1-10 mosfets, or 2 drivers for 12-20 mosfets. You just want to make sure everything is pretty symmetrical so that the drivers get turned on at the same time. Let's see, 20 mosfets would be 1000 amps. You aren't making a zilla are you?

EDIT!!!
Don't connect the outputs of the mosfet drivers. Have each driver just drive it's own group of mosfets. That's the word from the experts. I had that same question.

Originally Posted by edown

Suggestion: I put an LED on the driver output for a visual aid.. It helps with trouble shooting and just lets you see things are working before turning on the main contactor..

I'm doing an LED indicator on the next version. That's a really good idea.

[MPaulHolmes]

I have never tried 2 mosfet drivers, but I'm going to. EDown, if you try it, let me know how it goes. That would make for potentially a very powerful controller.

eco_generator: I'm so sorry! Please don't sue! hahaha!