Paul & Sabrina's cheap DIY 144v motor controller - Page 441 - Fuel Economy, Hypermiling, EcoModding News and Forum

adamj12b · 02-22-2011, 08:24 PM

Quote:

Originally Posted by LouMan

thanks Djbecker & Paul,
I only chose the hc04 hex becuase thats whats on the VLA's schematic to use.
anyway the hco4 has 6 invertors can use one to drive four for out put to the 4 vla's but also the only thing being driven inside the VLA is a opto led,
so theres no need to complicate anything just to drive 4 led's LOL

Paul what boards was you saling for $25 to help get money up I missed out on it?
I would like to get one if theres any left

Lou,

I highly doubt you need all 4 of those VLA modules to drive the IGBT's. What IGBT are you using? My guess is you could run 2 modules with 1 VLA. Might be able to run all 4 with 1 VLA. They are very powerful drivers. Let me know what IGBT u have and was it the VLA503?

-Adam

MPaulHolmes · 02-23-2011, 01:34 AM

Hey Louman! I think I have exactly 0 control boards left out of 10. I wish I woul dhave got 11 now. haha. I do have 1 power board for $45 if anyone wants it. Here's some pictures of the metals that came today!

no not a 2x4, a copper heat spreader! hahaha.

big awesome bus bars:

isolation strips. sort of long.

The bus bars came in 96" pieces since it's cheaper that way. That thing was sitting on my front porch. Oh ya!

The boards will be arriving on or around March 3. Oh heck ya. All the drilling will be done by then, and then it's time to assemble! We'll be driving or blowing crap up soon after that. burnouts here we come!

flores · 02-23-2011, 02:50 AM

He he he.. cool

do those bus bars really have to be that thick? They seam to be a bit oversized..

flores · 02-23-2011, 07:55 AM

"If it's worth doing.. it's worth overdoing" would Adam Savage say..

I get it..

MPaulHolmes · 02-23-2011, 11:49 AM

Ya, it makes for around 14watts of power loss from resistance at 1000 amps along the M- bus bar, where it is touching the powerboard. That's less than I thought, because I had ordered it thinking that 1000 amps was running down teh whole length of it, which it won't be. You will only get 1000 amps right at the end, after all the mosfets and diodes. At the back end, there will only be around 72 amps, then 0.8" after that 72*2 amps, and then 0.8" after that, 72*3 amps, etc... So adding up all the power losses from the individual pieces for the length of the bar is around 14w. Now, there will be some loss from the remaining inch or 2 at the end where M- sticks out, but that's just a few more watts. PLus, the dang mosfets will be putting out a heck of a lot more than that. I'm thinking that 1/4" x 3/4" would have been fine. haha. Oh well. At least now you have the equivalent of 00000000 GAUGE wire. Do they make octuple aught copper wire?

Oh, and I had been losing sleep over the loss of space for the current to flow on the bottom of the power board, and I wanted to add a little something special to the bottom of it. B- is just the battery amps, but I still wanted the full 1000 battery amps too. All the gaps between where the diodes poke through are about 0.1" wide, so I got some 3/32" square copper "wire" or "rod", I'm not sure which it is, and I'm going to solder that along the path, which should help keep those skinny little tracks cool. That's around 1" x 3/32" of copper cross sectional area, which is only needed for a few millimeters, so the power loss is going to be completely insignificant, and the bottom of the board will not vaporize!

harlequin2 · 02-24-2011, 03:54 AM

hey Paul, what are thge dimensions of that heat spreader?

adamj12b · 02-24-2011, 07:20 AM

Quote:

Originally Posted by MPaulHolmes

I'm thinking that 1/4" x 3/4" would have been fine. haha. Oh well. At least now you have the equivalent of 00000000 GAUGE wire. Do they make octuple aught copper wire?

Hey Paul,

They do! but after 4/0 they call it MCM. It starts at 250 and goes all the way to 2000. What you would be looking for is about 700MCM which has a cross section of 0.5498 in^2. If I remember correctly, you were using 1/2 x 1 bus bar. so this is a hair larger.

-Adam

MPaulHolmes · 02-24-2011, 10:40 AM

The heatspreader is 11" x 3/4" x 1.5". Actually, on each end there will be a 1/16" piece that has been milled down some so I can clamp it down so as to mill the top and sides so they are like a beautiful shiny mirror.

Adam... You are the man with the plan and you eat flan and you work for the ran(d) corporation.

harlequin2 · 02-24-2011, 02:52 PM

Quote:

Originally Posted by MPaulHolmes

The heatspreader is 11" x 3/4" x 1.5". Actually, on each end there will be a 1/16" piece that has been milled down some so I can clamp it down so as to mill the top and sides so they are like a beautiful shiny mirror.

Adam... You are the man with the plan and you eat flan and you work for the ran(d) corporation.

Is that the finished size after milling? If so, what size bar did you start with? I have to make one of these things.

MPaulHolmes · 02-24-2011, 03:16 PM

I'm just planning on shaving off maybe 1/100" or so, just deep enough so that it barely mills the whole surface. I usually do a test rectangle to see if the depth will hit everything, so the new size will maybe be 1/50" less for width and length, but 1/100" shorter for height, since there's no need to mill the bottom of it.