LCD Instrumentation for Cougar Controller

[harlequin2]

Hey Ian, how did you know a mosfet had blown?
I'm pretty sure mine are all working, but I have no idea how I'd know otherwise!

[ianbartie]

I blew 2 a couple of weeks ago when I was fiddling about trying to get the display to work. I had the controller in the car with the back off it so I could get to the control board. The control board is usually fixed to the base so it was hanging loose & I thing something was touching something it should not have been touching because when I turned on the ignition & the contactors closed there were some fireworks.
Inspection showed mosfets #2 & #3 were blown big time & 1 of their gate resistors had a very high resistance. Replaced the sad bits & put it back together with the back on this time.
I got a small pop when I turned everything back on - I though it may have been a tiny bit of crap from the previous event across the motor commutator or something. Could not find anything & nothing indicated anything happened to the controller because it was working.
During the week I was trying different controller settings, I noticed that the motor amps were not getting up to 511 like they were but more like 470 or so.
It was only because I had the controller out to make a keyhole mount for the bottom mounting screws (I discovered that I could not get to the botton screws with the front of the car on) I decided to have a quick look inside.
There was a small amount of soot that was not there before & a really close look showed #6 mosfet with a crack in it's case. I also found #10 gate resistor to be open circuit. Replaced these unhappy parts too.
No pops or smoke this time when the juice went on but this is when the display stopped showng motor & battery amps.

[harlequin2]

Aha, I see it all!
Fiddling is what Nero did and look what happened to HIM.
Not as bad as me connecting my original LogiSystems controller with B+ and B- reversed.......

[ianbartie]

I should know better by now but I just can't help myself.
I've labeled the controller M-, B-, B+M+ connections & have done the same to the cables so it is easy to match them up right.
It does seem that everyone who fools around with electric cars let some smoke out of something eventually.

[ianbartie]

I found the problem which was causing my display not to display serial stuff. Turned out to be the PCB header/connector for the serial info that I have used on the board.
It only has a finite number of plugs & unplugs & after that the connections become a bit erratic. Got a new one coming along with the bits to make up the charging monitor & some new mosfet clamps for the controller.
Will be OK once I stop unplugging the display 57 times a day to fiddle with it.

I seem to have the tacho bit sorted out now too although I had to resort to Plan B. I fitted the guts of an aftermarket SAAS tacho onto the VW dash panel after I removed the original drive setup. Fitted very nicely & even the spindle was the right diameter.
I had to use a Digital Speedo Corrector kit that I had lying around (also works on tachos) to get the tacho to read right because the SAAS scale & the VW scale were about 12% different.

I have the bits coming to get the fuel gauge working via the display & an LM2917 to hopefully make the temp gauge work like a battery amp gauge.

[mora]

I had peukert set at 1.15 in the latest .asm file I had saved. I changed it to 1.05 but still no noticeable change. I got funny behaviour of fuel gauge on video too, see

http://www.youtube.com/watch?v=rI2O1DhEVVI

It shows empty until 14% SOC is reached. Or does it have something to do with MTE/KTE?

[pnikolaj]

... especially when you are working with electronics.

I completed building the display about a month ago and powered it up with 12 volts and all was well. This past weekend I finally got a chance to mount it in the car. I spent 3-4 hours making the installation look real nice and decided it was time to connect the display to the traction battery. That's when the smoke appeared.

I failed to notice the pin-outs on the last page of Cougar LCD - PCB Assembly Instructions - Rev0.pdf and used page 9 of CougarLCD_User_Manual_Rev_1_3.pdf to determine the connections. I assumed that the pins read left to right and now realize after looking real close at the schematic that I applied 98 volts to the 12V feed for the buzzer. The board is now toast.

If anyone has a spare board they would be willing to sell I would greatly appreciate it. I now have a sad hole in the dash of my car that is begging for a display unit.

P.S.
I am offering my services to test instructions. Those who frequent the Paul & Sabrina's cheap DIY 144v motor controller thread will realize I made a similar error when connecting the controller for the first time- see post for a sample of my ability to mis-interpret instructions.

[Freyguy]

Originally Posted by mora

I had peukert set at 1.15 in the latest .asm file I had saved. I changed it to 1.05 but still no noticeable change. I got funny behaviour of fuel gauge on video too. It shows empty until 14% SOC is reached. Or does it have something to do with MTE/KTE?

Mora,
So you're saying that SOC stil drops too fast, even with 1.05? Could you send me your ASM file w/mods? I'd like to generate the hex file on my setup, then I'll send it back to you for programming.
Did you verify the resistance range & polarity of your sender first? Low resistance=full, higher resistance= empty. If this is not the case, then you would need a code mod to invert PWM.
If low resistance=empty, then depending on R20, it will probably sit at empty until SOC value (and "on" duty cycle) decreases to where average current through R20 is low enough to let needle climb to full.

[Freyguy]

Originally Posted by pnikolaj

... especially when you are working with electronics.
I failed to notice the pin-outs on the last page of Cougar LCD - PCB Assembly Instructions - Rev0.pdf and used page 9 of CougarLCD_User_Manual_Rev_1_3.pdf to determine the connections. I assumed that the pins read left to right and now realize after looking real close at the schematic that I applied 98 volts to the 12V feed for the buzzer. The board is now toast.

Pnikolaj,
Very sorry to hear about the board. If I had a spare I'd give it to you.
Schematics and wiring diagrams should never be used to determine physical orientation/location of connectors. Typically the silkcreen (overlay) on physical PCB would have a pin 1 indicator but I didn't have the room
An overlay drawing (like I included in the assembly instructions)or pin 1's called out on a picture of finished assembly are the next best thing.
I'll add the overlay to the manual right after wiring diagram. On wiring diagram I'll add note to reference overlay for pinout orientation. I'll make it part of package for version 1.4 release.

[mora]

Yes, SOC still drops a bit too fast. I'll need your email address for sending the file.

I didn't measure sender unit in any way when we took the car apart about one year ago. Stock '89 VW golf/rabbit. I didn't have a clue about Cougar LCD board back then, hehe. I thought I'll never need original fuel gauge but I saved it. Otherwise the fuel gauge interface works good, shows full when SOC is 100% and empty when SOC is 20%.