19 November 2009

The pattern is clear: Moisture

Forget cycling the ignition when there is a charging problem.  The cause  is moisture.

Mini, are you not doing the main work in southern California?  What "The Firesign Theater" called "the stinking desert"?  You guys need to take a Mini E up to Seattle and drive it around in the rain until you see this charging problem.  Here is what happened to me tonight, and I have seen it before:

Come home in the rain, wipers on fast for much of the drive.

Plug in the car.

The RED light comes on steady on the Clipper Creek wall mounted safety box.  (The GFCI tripped, but I ask that civilians please do not open the box to look at the LEDs.)

Unplug and plug back in, same RED light.  Sound like moisture to you?

Try it again, the Clipper Creek box stays on (GREEN light) and the car starts to charge but stops after 5 seconds.  OK, something dried out enough to keep the Clipper Creek box happy but the AC Propulsion electronics in the car sees the leakage now.

Unplug, try again, same thing.

Turn down the current to 12 amps, same thing.  Of course if it is moisture, the leakage is related to voltage, not to current.

So I get out the low voltage charging interface, the portable 120 volt box.  It charges fine.

After 30 seconds I switch back to 240 volts.  The car stops as before with the Clipper Creek wall box still on.

Switch back to 120 volts, where presumably the leakage current is lower and it does not set off the safety trip in the car.  Let it charge for a couple minutes while presumably drying out whatever got wet.

Switch back to  the 240 volt wall box, and all it well in the world.  It keeps charging.

Turn up the current to 50 amps.  It keeps charging.  Of course, since leakage is not related to - what?  Yes, not related to current but to applied voltage.

OK, Mini, you have moisture infiltrating on the AC side of the Power Electronics Unit (PEU).  My guess is either at the connector to grid power on the back drivers side, or under the hood at the PEU.  It cannot be after the PEU because the voltage is always the same on that side, only the current changes.  And we know that leakage is proportional to what?  Right, the voltage.

Is it time for  the big caulking gun?  Maybe.  Mini just needs to get it right on the production cars, I can deal with this.  This car drives more confidently than any other car.  Period.  I can deal with slight lack of confidence in the charger.

1 comment:

  1. I have not taken the aggressive diagnostics steps that you have, but I am now experiencing a constant charging issue. Sunny, cold, long distance or short. I plug in the cable upon pulling into the garage, and 85% of the time I get 5 seconds of charge and then the PEU clicks off. The other 15% I get the red light. I could switch to the 110v cable and mostly that works, but what I find works best is to let it sit for >1 hr, come back and plug it back in. this seems to be the most reliable way to fill up.

    Problem is when I forget to go back out (like this morning). I can get two days, so its ok to forget once. But the day I forget 2x it will be back to NJ Transit. :-(

    I a dropping off #269 on Monday to Morristown, but no one has asked me any questions about the problem. This is more diagnostic info that I have provided anyone. I guess they figure they will plug in the PEU and find any problem.

    we will see. can't wait to get my clunker loaner from Morristown. This is THE WORST