Drove the E up to High Point

Thanks to Chris for letting me charge up on the way to the very northern tip to New Jersey today.

Voltage at Chris' measured about 122 in the morning and 117 on the way home after dark.  No trouble charging either time.  Of course, the car would see about twice those numbers, or 244 to 234 volts. Well within ANSI specs.  Unlike at my house which  is often 253 volts and the Mini E won't fast charge.

By the way, the skiing was lousy, too many bare spots from all the wind.

The cavalry is on the way

I heard today from Clean Fuel Connections that the entourage from Mini will be visiting me in early mid January.  Not just to diagnose the charging issue but with a potential work around and possibly a modified (fixed?) car to see if it has trouble with my high line voltage.  I suspect mine is the highest of the bunch who are having trouble, which apparently numbers six.  Not bad, 1% of the total.  This is the sort of problem that needs to get figured out in the prototype stage.

Now, if I can get really technical for a moment - Mike, you might remember this from your Electrical Engineering days.

You don't need a 15 kilowatt transformer to lower the line voltage to get around this problem.  A transformer with a 12 volt 60 amp output could do the job theoretically.  Wire the output in series with one side of the 240 volt line but opposing phase (symmetry is not needed) and you drop from 240 volts nominal to 228 volts.  That should be a MUCH cheaper transformer.  I'll post a schematic in a few days maybe but I doubt something like this would comply with the electrical code, so it is academic.  Maybe try it on the 4th of July so that if it explodes, it would seem to be on purpose.  Ha ha.  Maybe I can find a picture of the cavalry with some explosions?

You can charge any car your want at Tom's restaurant

OK, this is about line line voltage, but not mine!

We visited Mike Graham today. His line was 244 point something volts which is well within ANSI specs, although on the high side. I could charge #458 fine, but Mike's #269 would not charge. So the over-voltage threshold in his car has drooped even lower than mine in the cold, but his line voltage is also lower than my 253ish. So we have similar problems at our respective homes.

Tom's restaurant is nearby Mike's home so we went over there to finish charging and get some DELICIOUS food and peek at his line voltage. As Tom told me, since he has industrial 3 phase power, the single phase feed is lower with a nominal of 208 volts. (For the geeks, that is 120 volts times the square root of 3, for 3 phase.) Tom's line actually read 204 point something today. And of course, no trouble charging. No one ever has had trouble charging at Tom's restaurant. Because the voltage there is lower.

Mini, are you taking notes? There will be a quiz when you make your house call. I am handing you the answer to this charging problem on a silver platter here.

Oh by the way, this long drive in a BIG blizzard. That traction control is Great. The heater is not dependable. Goes cold now and then. Need to leave the fan up on three.

I hope this is the last post about line voltage

Tonight I read the power line at about 250.1 volts and the Mini E would not even blink. Had to even dig out the clothes iron to get the line voltage down to 248 before she would charge.

It is nice to know what is going on finally with this charging problem. But it is rather frustrating to deal with and not without risks. I think this is the end of the data collection for me.

I think I got word through the ramparts and into engineering at Mini, although there is no confirmation. Had to use the back door to get someone to listen, but that is the way it is most places, including where I work. It is not an ideal situation, but the engineering department can get flooded with noise and distractions if the guards did not keep the Visigoths from the door.

Last night it worked

We got home with temperatures in the low 20's, line  voltage about 252.6 and of course the Mini E won't charge, not even one blink or click.

After turning on almost everything in the house, the line voltage drops to 250.0 and bingo!  It started charging and did not stop.  I was expecting to need to get it down to 249, since recently 249.2 was not far enough down.  Sounds like 249 to 250 is the threshold when temperatures are a bit below freezing.

I heard from a reputable source that the AC Propulsion safety limit (maybe there is another more official term?  Jason, can you comment?) should be 264 volts.  That gives plenty of margin past the ANSI spec of 252 max.  To bad it doesn't hold in the cold.

No dice tonight

This was a test of charging tonight. I get home at zero range (although the gauge floats back up to 11% when I turn it off) and temperature just below freezing. This is usually the worst combination for getting the fast charger to work. I measure 250.8 volts, not as high as usual, but 1.6 volts higher than last night which was warmer. So I am not surprised when Mini E #458 won't even try to charge from the fast charger. Note that 250.8 is within the ANSI standard.

I turn on all the big loads in the house. Space heaters, toaster, the few incandescent lights that have not been switched to CFLs. Voltage drops to about 250 and when I plug in the car, it blinks a few times but then stops. Well at least it tried. It noticed the difference. Usually, if it won't even blink on the first try, there continues to be no response for 30 minutes with the big wall box "charger".

So I turn on everything in the house, even open the door of the fridge until I hear it start. Voltage down to 249.2, like it was yesterday (except I didn't have to turn on anything yesterday to get down to 249.2, maybe the neighbors had something big on yesterday). The car blinks 8 times, more than last try but then it stops. Still, this makes sense, it is colder tonight by maybe 15 degrees even though I got the voltage down to yesterday's value.

OK, put it on the 120 volt cord, I am out of time tonight. At least it only needed 10 minutes on 120 volts before it would switch to the higher voltage fast charger.

I have an 8000 watt heater I have not used in a while since the sauna turned into storage space. I'll have to clean it out so I can turn it on. An 8 kilowatt load should pull the power line down by several volts. Best part is, it is just one switch, not 50 things all over the house.

Voltage tolerance in North America

I did find a spec for AC power line tolerance in North America, 114 to 126 volts. So technically my power line at home which is usually at 126.5 volts is too high, but I say AC Propulsion needs to be more tolerant in cold weather right after driving.

The Wikipedia link is here. The excerpt follows:

"In the United States[3] and Canada[4], national standards specify that the nominal voltage at the source should be 120 V and allow a range of 114 to 126 V (-5% to +5%). "

[3] ANSI C84.1: American National Standard for Electric Power Systems and Equipment—Voltage Ratings (60 Hertz)

Tonight my power line read below 250 volts, 249.2 to be precise. I had no trouble charging, it started immediately and kept going. I cannot remember the last time I did NOT have trouble with the fast charger. So this supports my theory. Then again, it was not so cold tonight. Tomorrow will tell. But maybe, just maybe Wile E. Coyote (my alter ego in this context) finally caught a valid theory.

Who knows why my line voltage was below 250 tonight. Coincidence? The idea that winter voltage is higher because all the Air Conditioners are off is interesting, but it does not explain why waiting will usually get the car to accept the fast charge. Then again, neither does my theory unless it is somehow related to battery voltage. And besides, I bet the power company regulates for load conditions.

I know waiting usually will get it to start charging again. But a couple times a month I take the boss out dancing when I get home from work with 1% charge left. If it doesn't start charging right away, we have to take the gas car. And she doesn't like the gas car anymore!

So you see, Mini, I had to figure it out myself. I couldn't wait for the house call. Because tomorrow night is dancing night. And it is very important to keep the boss happy! (That would be my wife.)