Paul & Sabrina's cheap DIY 144v motor controller

[krispyllama]

Finally read threw this blog. I have been reading for about a month (at work on breaks and on the cell, no real internet) I'm amazed at the work being done here, very inspirational. I can't wait to make a project of my own. I'm thinking of starting with an electric mountian bike cause of the gears. But back to the point. I find it interesting about the liquid cooling idea. I have not personally set up a system but I have seen many working mineral oil systems in computers and it can be easily setup for this. Also do you have the finished parts list and all info on your lighter bike version of the controller. You seem to be so excited with the car version that you skipped it (or I missed it) well I'm off to finish my work and get some rest. I hope to be a very active member on here. Keep up the good work all.

[MPaulHolmes]

krispyLlama! I love the idea of liquid cooling. I'll put together a parts list for the 72v 40amp bike controller. I never actually put one in a box with a heatsink and drove around. I only ran the bike in the garage, but it worked really well.

I've been working on the power section of the car's controller. Here are a few pictures:



Just a quick partial assembly. B+ and B- bus bars drilled and attached.


Here's a front view. There is a single capacitor temporarily attached. There will be a total of 24.


A view of the capacitor board side.


Another picture, for no particular reason.

I think I'll finish the power board and then break the control board circuit into pieces and test each part.

[Tango Charlie]

Originally Posted by MPaulHolmes

...I'll put together a parts list for the 72v 40amp bike controller. I never actually put one in a box with a heatsink and drove around. I only ran the bike in the garage, but it worked really well...

Would 40 amps be enough for a motorcycle? I looked at Bens Kawasaki conversion, but didn't see how many amps it uses.

[bennelson]

It would help if I had an ammeter on my motorcycle....Then I could tell you.

I do have amp-limiting as a feature on my motorcycle's Altrax AXE controller, so I could just set it to a max of 40 or 50, drive around, and see how it works.

That would have to wait until spring though. The cycle is in storage and I REALLY don't like riding in the snow...

[Intrigued]

Originally Posted by bennelson

That would have to wait until spring though. The cycle is in storage and I REALLY don't like riding in the snow...

WooHoo! When I was a kid I did it a lot! (Suzuki 120: light bike) Trying to take off was like "Advertures In Fish-tailing!!!" Used to pull the sled behind the bike! Anything over 30 will freeze your Bippy off, to borrow from Rowan and Martin's Laugh In... (Gotta have 39-itis to know about that one...)

Finally found a good pair of leather gloves so I could hang on to the Suzuki, which sure made things a lot more fun. There's nothing like trying to move tingling fingers that are well frostbitten...

Got caught in a hailstorm one time. Felt like I was going through a gauntlet where they were throwing baseballs!

...oh, wait a minute! Controller thread!!! ...bunch of words I don't know... AMPS!... bunch of words I don't know... VOLTS!... bunch of words I don't know... COPPER!

[Tango Charlie]

Originally Posted by Intrigued

...oh, wait a minute! Controller thread!!! ...bunch of words I don't know... AMPS!... bunch of words I don't know... VOLTS!... bunch of words I don't know... COPPER!

Ha! Join us here in the Nosebleed section of the bleachers! We're all gazing in on Paul and going, "Wow, that's really cool. Don't know whatinheck izzy talkin' about, but it's really cool. When he's done, maybe I'll build me one..."

Thanks, Ben. Come spring we'll revisit the amps question. An open source/homebuilt/low budget controller just might be the impetus (for me) to follow in your footsteps with an electric motorcycle.

[MPaulHolmes]

Originally Posted by Intrigued

...oh, wait a minute! Controller thread!!! ...bunch of words I don't know... AMPS!... bunch of words I don't know... VOLTS!... bunch of words I don't know... COPPER!

A dang copper gave me a ticket a while back. Some people think copper is an element. It's actually made of doughnut grease and pork.

Here's some more pictures of the progress for the power board. I finished soldering the capacitors. It was super easy with a 250 watt (I think) soldering gun from Radio Shack for $30! ya!


This is a picture of it temporarily and partially assembled.


And a side view.


And with an old diode on display. The silver things attached to the copper heat spreader press the diodes/mosfets against it to keep it cool.


The bars with all their dang holes!


With a layer removed.


And another layer removed.


Bottom of capacitor board, with capacitors soldered in place ya!


Little plastic things to keep the bolts isolated from the bottom of the board. They are to hold the M- bus bar in place! ya!

[bennelson]

That is looking SO good!

[esoneson]

Great job Paul! Your detailed explanations along with great pictures are making this a truly Open Source Project that can be followed by just about anyone........even a software guy like me.

Keep up the good work, you are making 144 Volt EV dreams a possibility.

Amazing magic.

Eric and the dogs.

[MPaulHolmes]

Thanks you guys! Your encouragement means a lot to me! Ben, I hope you can forgive me... Your heat sink needed to be "modded" (like your wife awhile back! Her leg done got broke!). Nothing serious. But to keep the integrity of the copper heat spreader, I am drilling a hole down the top through a couple fins, and then I'm drilling and tapping the top of the copper heat spreader, so I can bolt the heat sink to the heat spreader from the top rather than from below. That will leave more copper, and it's not fun drilling through 1.5" of copper.

I ordered some electrically conductive silver paste stuff ($25... gasp) to ensure a solid connection between the bus bars and the pcb. The bolting is probably plenty, but I don't know.. I just wanted to make super sure, and to increase the contact area.