Ben's "Cougar" ReVolt Controller

[bennelson]

The issue sure does seem related to the rain.

It poured all yesterday, and lightly all day today.

I wanted to run out to the grocery store, so I test turned on the Metro - no click. Green power indicator on, yellow logic light off.

I then put a box fan under the hood and ran it for ten minutes. Car turned right on after that.

[jackbauer]

hmmm. Interesting. One idea would be to dry the unit out and spray the control board with conformal coating to seal out any moisture. A likely area would be the crystal. Any disturbance to the tiny currents and voltages involved in the oscillator circuit may prevent the micro from starting.

[apowers]

I am using a cheap pot on the throttle and sometimes it does not start. I turn the key off and press the accelerator once then turn the key back on and it works . Corrosion on the pot I guess. There has been alot of rain around here too.
Alvin

[bennelson]

Originally Posted by apowers

I am using a cheap pot on the throttle and sometimes it does not start...
Alvin

That's pretty typical of cheap potentiometers. One of the few parts that I actually spent money on and bought new was a Curtis PB6 potentiometer.

I have that enclosed in a protective box.


Also, I talked with one of my electronics buddies last night. He said that to protect my circuit board, I could even just cover it with the same protective varnish that I used on my motor windings! Just mask off the LEDs and anything else I would want to see and blast away!

I will have to pull the controller out sometime soon, and check a few things over. When I do that, I will check the circuit board and decide what to do for maybe coating it.

Also, I think I want a little different case. It would be pretty cool to have one with a clear cover to show off the electronics. Maybe with some lights inside like those modded PC cases.

[adamj12b]

Originally Posted by bennelson

Also, I talked with one of my electronics buddies last night. He said that to protect my circuit board, I could even just cover it with the same protective varnish that I used on my motor windings! Just mask off the LEDs and anything else I would want to see and blast away!

Ben,

Before you do this, Take the board, and pop it in the toaster over at about 100-135 degrees F for about an hour. This will take all the moisture out of the fiberglass board and make sure it is DRY!. then coat it and I bet you will never have a problem again.

-Adam

[bennelson]

Should I use the whole wheat or sourdough setting?


I figured it would take at least a hair dryer. Low temp in some sort of oven sounds like a good plan.

[Tweety]

Hair dryer takes care of surface moisture... The fiberglass retains moisture though, so an oven is a must...

I honestly cant believe the board hasn't been varnished to this time! It's like 101 in electronics... You protect stuff from moisture either by varnish or by sealing them in a rubber casting thingie... (can't remember the english word right now)... I do that to anything that's going on a vehicle... Even the small unimportant stuff...

A waterproof enclosure is counterproductive unless the circuits are sealed as well, as it will never be 100% proof for moisture buildup...

[adamj12b]

OK,

I asked my PCB Assembly friend whats the best way to conformal coat a board. He said that you should use an acrylic or urethane based coating. You can actually just use something in a spray can from Home Depot. You will want to bake it for a few hours, the longer the better. Set it for between 120 and 150F and you will be all set. This will take most of the moisture out of the fiberglass and wont get trapped in. If you can leave it in longer, leave it longer.

After it comes out, coat it nicely. The urethane will be the easiest to modify if there are circuit mods needed.

-Adam

[bennelson]

Originally Posted by Tweety

I honestly cant believe the board hasn't been varnished to this time! It's like 101 in electronics...

Well, I never took electronics 101!
Seriously, this IS my first ever electronics project.

It makes perfect sense to to seal up the electronics with some sort of spray, I had just never heard of it before.

This entire car project is just one big learning experience.

[Tweety]

Heh... Adam is right on the solution...

I hope I didn't come of too much like a know-it-all... But the thing is it had actually not occured to me to even ask the question... I just assumed that once the board was assembled and tested it was sprayed with a coating of urethane varnish to protect it from moisture... That's the basic step one... I do that to all circuits I ever build... Regardless of where they are going to be...

In your case if you do that and put it in a sealed box it's OK... If it sits in a exposed area like where it gets splashes I'd consider sealing it completely... But on the other hand that makes repair/modification hard...