Paul & Sabrina's cheap DIY 144v motor controller

[watt-a-mezz]

Originally Posted by MPaulHolmes

hey, I got interviewed today!

Leaving Facebook... | Facebook

AND a couple days ago:
DIY DC Motor Controller

Hi,Paul. Looks like you have been busy. Listened to the podcast, and took a look at all of the pictures. I can see why you would want a pre made power board, the control board I could assemble (with large amounts of concentration). I would like to participate in a group buy, whenever you decide to do one. Hope the B'day party went well, and to you, and all the dads out there, have an awesome Fathers Day. Take care, Watt

[JayC]

Originally Posted by MPaulHolmes

hey, I got interviewed today!

Leaving Facebook... | Facebook

AND a couple days ago:
DIY DC Motor Controller

As announced on the cast, Make has a story in their blog:
Make: Online : Open source EV controller

[MPaulHolmes]

That's cool! I missed that part. Make magazine is a real magazine! That's hilarious! They also have an excellent article on making chocolate banana pops!

Hey Jimini! I think that 8" dual shaft motor would be perfect! Dual shaft is especially nice because you can easily add the rpm control later. We're going to add that feature to the controller in the next version so no-one can overrev the motor on accident.

[watt-a-mezz]

Was looking at the wiki for the controller and realized I had myself a duh moment. Power board is the one with the Mosfets, right? Did manage to find out how to tell them from the diodes, the legs are slightly different(diodes are square on top, Mosfets are rounded.) If I may, could I ask a couple questions, is there a reason that M- is pointing out the back, and how would you hook a pb-5 or 6potbox to it? Thanks, Watt

[MPaulHolmes]

watt! Power board is one with mosfets! ya! There are separate little connectors for the 2 PB-6 Pot wires. It's all good! And it doesn't matter which one you plug into which one. I have M- coming out the back, and B- and B+ coming out the front because of 2 reasons:

1. universal path length - Let's say you are an electron of electricity. Let's say you travel through the mosfet closest to the B- bar beginning (where the lug is attached) to the M- bar, and then all the way to the motor. That's nice.
Now let's say, you are an electron that travels all the way down B- to the mosfet furthest from the B- lug. You now go through the mosfet and are now on M-. Now you only have a tiny distance to travel to get to the motor.
Same distance! ya!

2. I don't have to cut the bus bars in any tricky way. I just take
3/4"x3/16"xLENGTH bus bars, drill holes in them, and attach them to the power section PCB. If they all came out the same side, they would be really close to each other. That's bad! ya!

I tried to salvage a copper heat spreader from the blown up controller, but all the old holes are in the wrong spots, so I decided to see if we can take $30 off the cost of a controller. I bought an aluminum heat spreader ($5.69) with the same dimensions, and just finished drilling all the dang holes in it. That will be Ben's heat spreader. I'm interested to see how it fares compared to the copper heat spreaders ($38 I think) that Joe and Adrian have. Also, I'm trying 16 of the old capacitors in Ben's controller. I think that will still be plenty. His will be a hair on the budget side. hehe. But if it works just fine, then we can drop the price down for parts by like $45 or $50 for everyone! Thanks for taking one for the team, Ben! haha!

Here's a direct link to the interview, not through facebook:
Evcast #246 ReVolting!

[watt-a-mezz]

Thanks for the reply,paul. Sounds like you have put a lot of thought into this design. The bars on my Kelly controller are rather close, I have to make sure the lug bolts don't touch. No wonder they burst into a cloud of smoky badness! Is the heat spreader the large block of metal M- sits on? I used to work with metals some years ago, and aluminum will dissipate heat more than copper, but you may have some warping. Copper is a whole lot harder(as you know from driling the stuff.) If it holds its shape it should work ok, kind of like an internal heatsink! take care, Watt

[MPaulHolmes]

Yes, the heat spreader is that big dang block of metal that sits on the M- bus bar. I heard that Aluminum can dissipate heat better, but also copper has a very high thermal conductivity, which I think means that it can suck the energy away faster from the mosfets/diodes, and then it's in contact with the aluminum plate that transmits the heat to the air more efficiently. (I think. hehe)

[wjdennis]

Originally Posted by blackpanther-st

Mosfets would be much preferred for this circuit as the voltage differences will always be minimal between the two packs.

Black Panther, this discussion has moved to another thread "Open ReVolt as Charger". But with the setup you mention, how would I control the amount of current that the lower C pack delivers? The purpose of the controller was to not let the lower C pack go above 70A. If the two packs were just connected through Mosfets, I wouldn't be limiting that. In that case, I might as well just do away with the Mosfets altogether and just connect the two packs directly to each other.

Bill

[adamj12b]

Hey Guys,

Thought some of you might like this, A video of one of the power boards being milled on my machine. It takes about 30 minutes total with changing tools and mounting the PCB to create a board. Thats alot better then Pauls 2-3 Hours by hand.

Enjoy

-Adam

http://www.youtube.com/watch?v=dZPjVxux4x4

[MazdaMatt]

*sigh*... beautiful