Fix for Roadster 80A Charging Bug part 2

Jul 29, 2014

TEG

I think the pilot signal reader circuitry has trouble getting a clean reading when the "off" phase is so short above 70A.



Not much room for error on the 80A signal...



80A duty cycle is right on the edge of triggering an error condition...

Precise measurement starts to become more important.

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Jul 29, 2014

hcsharp

TEG said: ?

I think the pilot signal reader circuitry has trouble getting a clean reading when the "off" phase is so short above 70A.
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Hard to believe that would be true. It's still a very long pulse (on or off) compared to many other signals that the car has to read. A measly 4mhz microcontroller costing less than $1 can measure that with very high accuracy.

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Jul 29, 2014

slcasner

TEG said: ?

Of course it will only be drawing 3.3kW or 6.0kW [depending on which version of LEAF charger in the car.]

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Which is a real shame when I show up with my Roadster needing to charge so I can continue on to Santa Barbara.

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Jul 29, 2014

TEG

hcsharp said: ?

Hard to believe that would be true. It's still a very long pulse (on or off) compared to many other signals that the car has to read. A measly 4mhz microcontroller costing less than $1 can measure that with very high accuracy.

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I think that some of EVSEs may be putting out a sloppy waveform that doesn't pull as high and low as it should. I haven't measured it myself, and am just relating some things I heard secondhand. I think the "fix" is to change how the algorithm decides what is "on" and what is "off".

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Jul 30, 2014

Curt

TEG said: ?

I think that some of EVSEs may be putting out a sloppy waveform that doesn't pull as high and low as it should. I haven't measured it myself, and am just relating some things I heard secondhand. I think the "fix" is to change how the algorithm decides what is "on" and what is "off".

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TEG - this is certainly true. I was at the Electric Sociability Run in Charles Town, WV a couple of months ago. The site has 14 Schneider Electric EVSEs, and not one of them would work with my Roadster (1.5). Other EVs, including Model S, had no problem.

There were some guys from Merit Solar there. They hooked up their testing equipment, and found that the pilot signal was out of spec on every one of the 14 stations.

Fortunately, they had brought along one of their portable EVSEs, and we were able to tap into a circuit at the Civic Center, giving me enough charge to to get through the day's activities and get home the next day.

I have since found two other locations with Schneider Electric EVSEs which would not work with my Roadster.

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Jul 30, 2014

djp

Yes, the Schneider stations are out of spec. I have a few near me that don't work either.

Ground Fault Threshold for Model S

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Jul 30, 2014

TEG

Curt said: ?

TEG - this is certainly true. I was at the Electric Sociability Run in Charles Town, WV a couple of months ago. The site has 14 Schneider Electric EVSEs, and not one of them would work with my Roadster (1.5). Other EVs, including Model S, had no problem...

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I think that is more of a ground fault detection issue, not necessarily an issue with the pilot signal.

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