Paul & Sabrina's cheap DIY 144v motor controller

[Blue Bomber Man]

Excellent work! Glad to see this project is being so successful. At first I thought it was kinda noisy, but then external cam showed that is really quite quiet. I assume the interior is completely gutted and doesn't insulate any sound from the components.

Would measuring the input and output voltages of your controller be a valid way of establishing the units efficiency?

Looking forward to seeing the results from pushing it harder =)

Good luck and congratulations!

[MPaulHolmes]

The interior is COMPLETELY gutted! It isn't as loud as the camera makes it sound, though. It amplifies certain sounds. It is actually quieter than my regular car, as least to my ears.

That's a great question about the efficiency. I'm not sure. Maybe

the average V_in*I_in = V_out*I_out + HEAT_LOSS?

I need to think about that one.

I had to delete the video and re-upload it! It got muted on youtube because I had a song on there that was a copyright violation I guess. That's a first! Man, they are so touchy these days!

[bennelson]

This is going to make one heck of an INSTRUCTABLEs!

Wait until they have a good contest though!

I put up my instructable on "how to build an electric car" a few days before I found out about the $20,000 in Sears Tools contest.

The winner of that contest was a garbage car, and second place was some electric bike set up. If I had waited just a tad longer, I KNOW I coulda been a contender!!!!!

[MPaulHolmes]

Ben, we will own that contest! 2nd place was an electric bike?! hahaha! 1st was a garbage car? I have a garbage car! hehe. It was $40 (after the motor sold) and it's electric! hahaha!!!

I'm going to try and fine tune the process with a second controller. I think version 2 will be much faster and simpler. Plus, I'll be using 2 sided PCB for the power section, which will simplify things considerably. It's only 3 ounce copper though, so I might have to lay down some extra solder on the capacitor side. Doing the instructable is a great idea.

[TheSGC]

Wow, nice job! My EV is undergoing a motor upgrade at the moment, and I only have a 96 volt 400 AMP Kelly to get me moving, but it works.

I'm curious, what price are you thinking for this controller? The clear casing is just awesome.

I have a controller design in the works, but it's a modular based design and I probably won't have a working batch of prototypes until summer time and classes are over.

[MPaulHolmes]

My loose plan was to do up a super careful set of directions, and it would be nice if there could be at least 10 kits so that the prices at Digikey would be like 20% cheaper (because 10 is often the magic number for volume discounts). Then people would make their own. The directions will be simple enough that it would just be tedious and not very technical. People might have to outsource for their power board etching. I could do it, but it takes a few hours on the mill. I heard that china does it in bulk for like $40 or $45 per board, but there's also shipping. I might charge something like $35 or $40, since it's really tedious, but better than working at Taco Bell, which I might have to do this summer. Grr...!

Other than etching the power board, I think there are no other special tools other than drills and screw drivers and a soldering iron and high wattage soldering gun (for the power section). The gun can be bought for $30. I could do the soldering too. Maybe there could be different categories of assembly. Partially assembled, no assembly, etc... If it takes none of my time, then it won't cost anything (all the directions will be free of course)!

I'm hoping to maybe also sell the occasional controller on Ebay to supplement the cost of improvements like Sync-Rect and much higher power versions. Maybe even an IGBT version and an AC controller, and charger. All open source of course!

[Tango Charlie]

Congrats on the successful test drives! So very very cool!

[tinkerdave]

Congrats! Don't you just love it when a plan comes together!

Know of anybody that has done a BMW 318i conversion? Seems like the adapter plate is the toughest part.

Put me on the list for a controller kit!!!

Good Job!

[MPaulHolmes]

Thanks you guys! I've been working on a controller cost spreadsheet. It will depend on how the parts are ordered. It's sort of hard to explain. If a small group of people order the parts at the same time to the same destination, and then they get mailed from that location, you pay for one whopper load to be shipped and then middle man handling (but that's not that tough I bet! Maybe divvy out everything and then put them in a bunch of separate boxes, and then shipping to each house. The rather large benefit of this is that you can save between 10% and 50% on the price of components from digikey (and the heat sinks).

[MazdaMatt]

Paul!! CONGRATS! (been gone all weekend, missed 2 pages of posts!)

Huge milestone complete with ZERO burn wounds!

Okay, i need to be honest here... your control algorithm sucks. I am going to write a new one for you when I get a chance. How's this for a concept - Pedal position is DIRECTLY proportional to CURRENT. This way, your current limiter only matters in hardware failure, your low-RPM cruising is just as easy to control as your high RPM driving, you get fine current control in all situations. Pedal up is 0amps, floored is 499amps - always.