Paul & Sabrina's cheap DIY 144v motor controller

[MPaulHolmes]

Almost $5, SOIC8 package. The attiny is like $0.80 or something. And if I'm using 6 of those, it adds up. The transformer is actually a line filter. 1:1 turn ratio. I used 3mH last time, and 1mH this time. If you put in around 15v, you can get about 13.8v on the secondary. All 6 outputs agree to about +/- 0.05 volts.

[sawickm]

Originally Posted by MPaulHolmes

Almost $5, SOIC8 package. The attiny is like $0.80 or something. And if I'm using 6 of those, it adds up.

Thanks for the info on the transformer Paul! The IR2085 was just an example i'm sure another could be found cheaper. If you bought them in quantities of 200 they would be half the cost. But the price would still be 3x the price of the ATTiny's. How much work is it to program 6x of those ATTiny's?

-Mark

[MPaulHolmes]

EDIT: If I only need a single attiny, then I only need a single one of those! haha duh what was I thinking!? hahaha.

Oh you just need a single attiny driving a single mosfet driver which pushes and pulls 6 line filters. They take me about 30 seconds to program each one, and I gladly work for $10/hr, so that means it's worth it. haha. Another benefit is if the attiny were to fail and quit pulsing, all 6 supplies go to zero at the same time.

[isaac_alaska]

It's hard to see, but the entire top of the capacitor bus plates are covered in 7 mil adhesive backed electrical insulating mylar. so even with the lid off the enclosure, it would be pretty difficult to short anything out



Had to build an input filter to the dc-dc converter so the voltage can't rise faster than 10V per uS. i series connected a 5 amp fuse, 68uH inductor, and 10ohm NTC thermistor. as the thermistor heats up, its resistance drops to less than half an ohm. excellent automatic pre-charge


Another view of my input filter



You can see all the filter caps. I used a Vicor dc-dc converter, which was a little cheaper and WAY smaller than anything else i could find. however, it's pretty much just a converter (mine was built to charge a battery, they custom build them one at a time.) They dont' come with any internal safetys or fuses or anything.



Couldn't figure out how to make the wiring look nicer on the dc-dc converter. it's hard to add terminals to an axial capacitor with leads that are probably 30 awg. so i fixed it!

[sawickm]

Originally Posted by isaac_alaska

isaac_alaska,

Where are you mounting the batteries? Under the seat of the snowmobile? It looks like the new controller takes up the whole engine compartment!

Nice EV project can't wait to see it run! We have a winter storm heading to Southeastern Michigan tonight 5 to 8 inches of snow, could use your electric snowmobile around here tomorrow!

Keep up the good work!

-Mark

[isaac_alaska]

Mark, I'll be in Michigan with it on march 3rd! Up in houghton... Not exactly southeast but the same state anyway haha. Batteries fit above the motor and extend back into where the fuel tank went

[DJBecker]

Originally Posted by isaac_alaska

Mark, I'll be in Michigan with it on march 3rd! Up in houghton... Not exactly southeast but the same state anyway haha. Batteries fit above the motor and extend back into where the fuel tank went

In Houghton, where MTU is located?

One of the guys that I used to work with moved there to be a professor at MTU. He comes back to the east coast occasionally, and lends a hand with our EV project. He was a one that figured out that our armature was spinning on the stationary motor shaft. That was after months of trying to figure out if the screeching noise going uphill was caused by the motor controller firmware (modified countless times), bearings (replaced), transmission (replaced), coupler (re-made five times), armature position (spacers on case and bearing seat re-cut on a lathe).

I understand that it's warm and sunny there most of the time. Everyone has snowmobiles, but it's never cold enough to use them. Or something like that.

[MPaulHolmes]

Originally Posted by keathreen

When i goes to home ,my husband alays worry ,what should i do?

ROFL. What the heck?! I think you should never ever goes home ever again. Then he will stop worrying.

[isaac_alaska]

Originally Posted by DJBecker

In Houghton, where MTU is located?

One of the guys that I used to work with moved there to be a professor at MTU. He comes back to the east coast occasionally, and lends a hand with our EV project. He was a one that figured out that our armature was spinning on the stationary motor shaft. That was after months of trying to figure out if the screeching noise going uphill was caused by the motor controller firmware (modified countless times), bearings (replaced), transmission (replaced), coupler (re-made five times), armature position (spacers on case and bearing seat re-cut on a lathe).

I understand that it's warm and sunny there most of the time. Everyone has snowmobiles, but it's never cold enough to use them. Or something like that.

Yeah, exactly at MTU! they are entering an electric machine of their own, it's rear-driven, which offers lots of benefits on a track powered vehicle. wisconsin maddison will also be there, as well as south dakota school school of mines, a group from canada, and i think a couple of others.

incidentally, here's another video of the machine, the camera guy came and jumped on and interviewed me while we drove around haha

http://www.youtube.com/watch?v=s1sbd...&feature=share

[MPaulHolmes]

And who can forget these?!

http://www.youtube.com/watch?v=GiSRnK-w1Ms

http://www.youtube.com/watch?v=0CL2D...pUE5yHsf5AQd9-