Paul & Sabrina's cheap DIY 144v motor controller

[sawickm]

Paul,

If you are having problems, send me the DesignSpark PCB you want gerber files for, I will create them for you and send you back a "gerber package" to have your board fabricated.

-Mark

[MPaulHolmes]

For "plot type" do I choose Artwork, Outline, or Drill Ident Drawing?

And under Settings, do I choose Plot Board Outline UNPLATED, PLATED, or both?

[sawickm]

Hi Paul,

Originally Posted by MPaulHolmes

For "plot type" do I choose Artwork, Outline, or Drill Ident Drawing?

The "plot type" should be "Artwork" for all gerber files.

And under Settings, do I choose Plot Board Outline UNPLATED, PLATED, or both

I would add corner markers (components) to all the artwork layers. But you could add the board outline to all your artwork layers. The board house will remove they if they don't need them.

I would also select "Unplated" for the board outline.

Check out the outputed gerber files in a "WYSIWYG" gerber veiwer to make sure that they are exactly how you want them.

-Mark

[jyanof]

The good news is that the controller still works. The bad news is that a couple weeks ago it went 'poof'!

Here's the story:

I drive to work, everything is fine. I get in to leave for lunch and notice the voltage meter reads 0V instead of pack voltage (it's after the precharge resistor, so it really measures voltage across the caps, and they weren't charging). Unfortunately, I thought the meter was acting weird, so I closed pressed the pedal which closed the main contactor. The car instantly lurched a few feet until the contactor opened and the dreaded smoke and dead electronics smell emanated from under the hood.

So, had it towed and took the controller apart. The whole album is here: Picasa Web Albums - Joseph - controller fa...

It looked pretty bad:



One bolt was blown apart:



Which one of these things is not like the other?



I tried to clean the bolt as best as I could...


One of the legs of one diode near the bolt was blown apart.


There's copper blasted onto the nearby bus bar and a trough was blasted into the solder.



Two of the nearby caps were blasted too. They turned out to be internally shorted.



This is what the bottom of the heat spreader looked like. A small channel was cut from the bore of the bolt hole to the outer edge.



The insulating PCB strip that touches the heat spreader mirrors the damage.


There was definitely something going on here between the B- layer and the insulation strip. The two layers were stuck together 360 degrees and pulling the insulating PCB off stretched it apart and made it baloon like that.




So, the theory is that the heat shrink that insulated the bolt from the B- and M- layers got compromised. Paul originally put it together and said that some of the bolts were a little tight going in. Maybe after a year and 6000 miles of vibration and thermal cycling, the threads of the bolt worked through the heatshring. Eventually, both the B- layer and the M- bus bar contacted the bolt and 144v started an arc that blew through some of the PCB copper and the bolt. The resulting plasma shot out between the cracks, bored the hole in the heat spreader and took out the diode leg and the caps.

The fix:

Fran suggested an easy check to test the mosfets. They resistance from Gate to Source should ready infinite. Turns out the one mosfet opposite of the blown diode read a few kOhms, so that was replaced along with the diode and caps.

I found some perfect nylon flanged bushings at Ace Hardware. They're 1/4" ID and 1/2" long and pretty much fit right into the holes already drilled through the heat spreader and PCBs. Some were tight. But, they should provide good insulation of the bolt and various hot things it passes through.



The flange diameter is 1/2", so the holes in the one insulation strip needed to be larger so the fit around the flange. Both the flange and the PCB thickness is 1/16".



Everything back together!



Given the amount of damage, 1 mosfet, 1 diode, 2 caps, and $3 worth of nylon bushings from Ace is not too bad! Paul was great helping with getting parts. If anyone has their controller apart, this modifcation would be pretty easy to do. It would take quite a bit of work getting the controller apart.

I've only taken a couple of trips with the fixed controller, but so far so good!

[bennelson]

Ya know, one of the most amazing things about these projects is that you CAN fix it.

Any of the problems I have seen so far with these controllers are things that could happen on a Curtis or Alltrax. But with the Open Revolt, you can FIX it.

Not so easy when the big boys won't give you a circuit diagram and fill the inside with epoxy!

[Weisheimer]

This is a great write up.
Thermal expansion/contraction and vehicle vibration can cause all kinds
of troubles and this is a good example including a fix.

Thanks Joe!

This isn't related, but I looked at your photo album and noticed a pretty nifty looking
electric AC system. Did you do a write up on that anywhere?

[jyanof]

Originally Posted by Weisheimer

This isn't related, but I looked at your photo album and noticed a pretty nifty looking
electric AC system. Did you do a write up on that anywhere?

I never really got around to doing a full write up. I didn't really get to test it until this summer and it's undersized so I'm not really satisfied with it. There were some guys on diyEcar that were talking about trying this, so I chimed in with my experience. (scroll about half way down).

EV air conditioning - Page 16 - DIY Electric Car Forums

[MPaulHolmes]

Oh, you were talking about Joe. Never mind what I just wrote. hahaha.

[Flatmann100]

Hi guys, Paul I just crossed the 2,000 mile mark and still going great.

Looking at the pics from Joe.... ouch! Sure do like the serviceability, priceless.

In the past couple of weeks I've been making some adjustments to my controller to dial it in with my setup. I am checking to see it’s happy at the end of the day by telling it how good a job it is doing with a pat on the hood for good measure.

[Nevyn]

The power board is the same no matter if you have the "regular" control board or the planned SR board, right?