When I first attempted DCFC in Mission Viejo "Shops", I had some problems, and it was "resolved" by tugging on the connector handle. Since then, I had various issues with charging, many attributed to NRG eVgo station made by ABB. At least I thought the charger was the problem.
As summer rolled around and temperature rise, I was having more and more issues. I was able to charge with jiggling the connector handle and restart charging 6 times in about 90% of the cases before summer, although very few were charging without errors. With higher temperature, I wasn't able to charge in over 50% of the chargers! I was about ready to return the car to Chevy and tell them to F-OFF when I was almost stranded after having 3 DCFC failures on the way to Drive Electric Event in Los Angeles. Stranded at EV event with 8 hours to wait before being able to drive home is pretty sad for EV.
Then I remembered a forum discussions on this very problem. At the time, I was able to charge most of the time, albeit with several errors and restarts. Now that the situation is desperate that I decided to look into it further. Thanks to http://www.mychevysparkev.com, I was able to find some information on GM service bulletin regarding "Intermittent Unable to Charge from DC Fast Charge – 2014-2015 Chevrolet Spark EV" by "Vitaly". It's basically GM service bulletin PI1382.
The crux of the problem is that SparkEV charging connector is almost 90 degrees and rectangular whereas fast charger is expecting roughly 45 degrees and trapezoidal shape. I suggest everyone with SparkEV to have this done if DCFC is not 100% (or 99%) success. Most failures are SparkEV issue, not eVgo / ABB.
|cropped from http://rema-ev.com/wordpress/wp-content/uploads/2012/03/REMA-inlet-Plug-1.jpg|
But below is connector on SparkEV. Note the shaded area that need to be removed described by Vitaly. "Starting at point “1” as shown above, measure 6 mm to point “2” and 3 mm to point “4.” The material above that mark (shown in red above) will be the material removed. Repeat on second receptacle guide."
Why would poor fitting connector cause the problem? Since there's no way to track down the exact problem without equipment, these are my guesses. I doubt it's the high current contacts getting loose. Rather, it's probably the tiny signal pins that were getting poor contact. Following are some problems and plausible explanations.
Jiggling handle: Many people, including myself, jiggled the connector handle to connect and allowed it to charge. Jiggling might have given it just enough contact time for signals to be transceived.
Errors after 10 to 12 seconds: Often, DCFC would error out within 12 seconds. This could be the time that contact was broken after initially made when handle was first inserted and the internal timeout error occurred.
Random errors after minutes into charging: As the contacts heat up, especially the high current contacts, there would be thermal expansion of the mechanics, which could have made poorer contact for the signal pins and cause error.
Problem more severe in hot weather: The problem wasn't as severe during Spring and early summer with milder temperatures. With temperature rise, the expansion of various parts of the connector probably made the poorly fitting contacts even worse, often times making it impossible to charge as was in my case.
But then, it's not important why it's not working, just that it's not working. One should get it fixed ASAP.