Paul & Sabrina's cheap DIY 144v motor controller

[MPaulHolmes]

I wrote an 18 page assembly (it's not that bad. there are a lot of pictures), but it's in Open Office, and it's 15 MB. I'm going to try changing it to PDF, and posting it on our web site and on the wiki. ya!

I found that there were a few holes in the process as far as pictures were concerned. Also, there were a few spots where some video is needed, so I'll do that.

[fritzgutten]

Hey Paul,
if you wanted me to I would be willing to do some editing, i'm an open office user and an unemployed techwriter
I can get you a log in for my site if you want to drop it to me.
fred

[MPaulHolmes]

Yo, Fred! I want!

[blowncurtice]

i think there was a discussion on the heat spreader somewhere but I can't find it, can the heat spreader be alloy or should it be copper.

[MPaulHolmes]

I believe the heat spreader CAN be aluminum (but it can't be an aluminum can). That's what Ben's is, and it seems to work fine in my car. I haven't done any tests to time how long it takes the heatspreader to reach a given temperature based on a given current. Ian of Zeva uses aluminum. I've tried both aluminum and C110 Copper. Joe's is Copper. The copper heat spreader costs around $40 or so, and the aluminum one is around $5. If the difference is negligible, then I think I would use Aluminum since it's so much cheaper. Copper adds another couple pounds to the weight of the controller too.

[blowncurtice]

What are the case dimentions and what thickness did you use for the base plate.
John

[MPaulHolmes]

I think John is secretly working on something! hehe.

Enclosure inside dimensions: 3.5 inches tall, 6.75 inches wide, 11 inches long.
Wings (what are they called?): about 0.75 inches wide.

Baseplate dimensions: About 8 inches by 11 inches by 3/8 inches.

Go John!

[blowncurtice]

I am trying to cut the cost of the controller for myself, having said that I still want a very good reliable controller, hence I would go for the larger power capacitors in the latest version. I believe that someone on the forum is advocating extruded alloy plates bolted together for the case, this would probably have better heat transfer properties than sheet alloy bent to form a case like the one from Hondo,but I can get an alloy case bent up for no more than $15.00 and another$5.00 for a good base plate, combine this with an alloy heat spreader and I may not have the gold plated version but I think it will serve my purpose. I have a 1985 Camira station wagon,kerb weight with no passengers is 1135Kg, I have a 9" advanced DC motor and drive conservatively I try not to exceed 200amps and most of my driving is highway at about 80KPH this pulls less than 100Amps cruising and is mostly below 50Amps. I will have a case bent up tomorrow and post a photo and a better idea of cost, this may not help our friends in the US as postage would probably be expensive and those of us in Australia may be able to get it made localy cheaper or if they prefer make one from extruded aloy but for those interested this may be an option.
John

[MPaulHolmes]

Hey John!

Joe was telling me that this controller with the larger capacitors takes quite a bit longer to precharge. Like 10 seconds with a 500 Ohm resistor instead of the few seconds that the Curtis 1231C would take. The nice thing is, the more ripple caps the better, but you could probably get away with smaller ones I think.

[JayC]

Originally Posted by MPaulHolmes

I think John is secretly working on something! hehe.

Enclosure inside dimensions: 3.5 inches tall, 6.75 inches wide, 11 inches long.
Wings (what are they called?): about 0.75 inches wide.

Baseplate dimensions: About 8 inches by 11 inches by 3/8 inches.

Go John!

I would call them mounting flanges if I understood you correctly.

BTW, working up a BOM for an SMD version of the controller is a PITA, kudos to those that worked on these.

Jay