ChargePoint Charging Question

[kevin1956murray]

Below is an email I just got from Driver Support at Chargepoint. I have little hope that I will soon be able to get the full 3kW rate after pauses on Chargepoint Power Managed dual cord stations.


Jul 11, 14:44 MST

Kevin,

Thank you for providing more information. As I said before this has been escalated and the engineers will work on it. I don't have a time frame for that so I can't comment on when it could be fixed.

I do know from other customers that when their cars pause and resume it picks back up at the normal rate. The charging station will provide the vehicle with the right amount of electricity based on what the vehicle requests. I've seen the pauses from several other manufactures, Tesla, Toyota, BMW, and the stations do resume correctly.

Steve Thomson
Manager, Driver Support
ChargePoint | chargepoint.com

[kevin1956murray]

I discovered this morning that just pressing the "release knob" on the charger plug (as if I were going to pull it out, but not actually then pulling out the plug) causes the low 1.1kW "post pause" charge rate to return to 3kW. (See the trace below.)

I have read that pressing the release knob signals to the EV charger to turn off the high voltage, I think with the intent to avoid arcing at the connector pins and to be safer. I thought it would stay off, but this morning it caused my charge rate to return to the desired 3kW rate. Unfortunately this does not help me, since to press that knob I have to return to the car physically. But I am thinking that it is another clue on what causes this low charge rate after a pause.

This happened while a Volt was plugged in the whole time on the other cord.

[kevin1956murray]

This morning I tried imitating/inducing a pause by holding the release button on the plug down, while staying plugged in. That did not work. A momentary press seems to stop the charging just momentarily, but a longer press (like a second or more) seems to cause the station to "say good-bye". (The little lightning bolt graphic on the station's display goes hollow, and the station may actually show a text bubble showing something like "Good-bye, see you later".)

The picture below shows that at least one of the dual cord stations that will charge at just 1.1kW for my MiEV is software version 4.3.5.70.

I do not know for sure if this version is necessarily indicative of the Power Management (sharing) option.

[kevin1956murray]

Further Googling reveals that station's software version does not indicate the "Power Management" option or not. That power sharing kit is jumpers and labels. (See a screenshot of Appendix C below.) I intend to look closer for labels, but as of now I am not sure they are on the outside of the stations. (They may be inside covers.)

But the 24A per station value (visible by pressing Help and scrolling down) may be a pretty good indicator that power sharing is in place.

[JoeS]

kevin, thanks for the updates.

Had you tried using the Remote while plugged in? Activating it and setting the ON time to zero I *think* suspends the charging and only after you then put in the ON-->OFF time and get the ENTER confirmed does the charging resume.

I will ask my friend if he's familiar with the software revisions on the station. I haven't yet set up a meeting with him to perform our test.

[kevin1956murray]

This morning I tried to replicate the low charge rate problem by inducing a pause with the remote.

Long story short: After both a short 20 second and a longer 6 minute "remote induced" pause, the charge rate returned well to the 3kW rate. And interestingly, since the car (as usual) paused itself and came out at a low rate, I found that in that "funk state" I could not induce a pause with the remote. I could only get the dash light charging indicator to flash off for a half second, then it would go back on. So then at home I tried the "remote pause" while plugged into my 240V line, and it would pause. But plugged into my 120V charging line it would not pause, other than the 1/2 flash off of the dash indicator. So it almost seems like the car thinks it is only being charged at 120V when it is in its post pause "funk state".

The trace below is notated with what I was doing at each change in the charging rate.



I had been hoping that stations that show they can do 32A per cord would not be the kind of station that gives me the low rate after pausing, but the station in the picture below does routinely return to a low rate after a pause. Interestingly, that rate seems to be 1.35kW, not the 1.1kW I see on a station that claims 24A per cord.




After the car induced pause, the station readout indicated that it seemed to be ready to charge up to 6.6kW, when my trace/app was only showing 1.35kW.




During the 6 minute long "remote induced" pause, the station appeared to be ready to offer a lower value of 4.0 kW. (Note the "hollow" lightning bolt, indicating that charge is not taking place.)



So I am back to thinking that after a car induced pause my MiEV is somehow not getting both poles of the charger. But my understanding of 240V is that since they are out of phase, the other pole is the "return line", and the ground line is there for just in case there is a short.

[JoeS]

Wow, kevin1956murray thanks for doing the Remote test. Disappointing, as I was hoping that would be a shortcut in lieu of waiting for that timeout to occur.

I'll ask my ChargePoint friend to be sure to review these last few pages of this thread to see what he can make of it.

I'm afraid that we're still needing to perform an instrumented test to determine whether it's the car or the EVSE.

BTW, the ac power typically supplied at home in North America is usually referred-to as "split phase", with two 'hots' and no current flowing through the ground connection (it's actually two points from a three-phase delta configuration). That's why dryers and ovens switched over to the four-prong connector so that 120vac (used for various panel controls and indicators) return current can now flow through the Neutral conductor and leave the Ground wire intact (recognizing that Ground and Neutral are tied together at the power input panel). Commercial EVSEs often use two legs from a three-phase Wye circuit (which means 208vac) and results in reduced power when compared to split-phase 240vac.

[kevin1956murray]

This morning, as I was walking back towards my charging MiEV (about 3 minutes from the car), I could see on the app that it had just gone into the pause.

When I got there, I snapped a picture of the station's display during a pause (the first picture below). It showed that the station was offering 1.15kW, with a 'filled in' lightning bolt, meaning the car was offering voltage to charge, but at reduced power. I believe it was still in the pause. (Every 5 minute read points loses some visibility.)

I then (during the pause I think) momentarily pressed the release button on the plug, but I did not unplug from the car. I did this since I have seen in the past that this gets charging to go back high (3 kW for my car). I heard a 'thunk' from the station, saw that the lightning bolt display went hollow (power off), and then it filled in again, now showing 6.6kW available. (Second picture below.) So then I waited to see at what kW rate would result at the end of the pause.

The trace is shown below the pictures. It came out of the pause at 3kW, which is what I would like to have happen without me being there.

Soon I plan to survey the stations at a shopping center near me, where I am bound do find some cars still plugged in that are done charging. My bet is that the display will look like the first picture below, where the station has a filled in lightning bolt, but shows it is offering just 1.15 kW to that done car.

[JoeS]

...Soon I plan to survey the stations at a shopping center near me, where I am bound do find some cars still plugged in that are done charging. My bet is that the display will look like the first picture below, where the station has a filled in lightning bolt, but shows it is offering just 1.15 kW to that done car...

That is yet another scenario that would support your argument, but which we haven't been looking for. Be great to get a photo of that and I'll try to look around and see if I can also find that. In the scenario you just painted, we know that if the i-MiEV (or any other car) plugs in it will get full power and not the 1.5kW.

Kevin, thanks for this and I'll continue pointing my friend to this thread. The question remains: is it the car requesting the reduced power or is it the EVSE forcing the reduced power at the point in time when the car gets out of the 'timeout'?

Based on the car's behavior with all other EVSEs we believe the car is asking for full power after the 'timeout'. We need to show this by performing a controlled test.

I did exchange some emails with my friend and he's just returned and is overloaded. We're targeting early August to get together and run the test and I sure wish we had some way of knowing when the 'timeout' occurs in order to save us all some time.

[kevin1956murray]

This morning I charged some at home, so that my MiEV would more likely get fully charged while I was on my usual routine at the station that reduces my power during and after the MiEV's pause.

The pictures below show the trace, and the displays at the start of charge, and near the end of charge. Notably, near the end of charge (when the car had already tapered itself down below 1.5kW, that side of the station's display showed that it was only providing 1.5kW, very similar to during and after a MiEV induced pause. So it sure does seem like the MiEV's pause is being interpreted by the station as the car being done (or nearly done) charging.

I also stopped by that Nordstom shopping center where I hoped to see a few other cars that where done charging but still plugged in, to see what power they were being offered. Unfortunately, even though the stations are the same model CT 4020 HD GW, and the same software version 4.3.5.70, the displays did not show a kW value for each side. The display just has a comment "6.6kW per side", which I do not think is real time data. (That is the third display picture below.)

Since my usual 'Presidium Laurel' station says "6.6kW Shared", while the Nordstrom stations say "6.6kW per port", I think I now need to try out the Nordstom chargers for a full charge, to see how my car's trace looks coming out of a pause. I'm hoping that being not 'shared', the Nordstrom dual cord stations will come out of my MiEV's pause at the full 3.1kW. (This may not pan out, since I know when I am plugged in next to a high drawing Tesla at Nordstrom I only got 2.86kW this morning. Still, a nearly continual 2.86kW would be better than all afternoon at a post-pause 1.1kW. Maybe the 2.86 value is from the 208V value from 2 legs of 3 phase, and not from being shared.)

This morning's trace:




Display at the start of charging:



Display at about 9:55am, in the shallow taper off:



Shopping center (Nordstom parking ramp), showing less visibility to each side's power: