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:

 

[kevin1956murray]

Now that I realize that there are "shared" and "per port" type of dual cord ChargePoint stations, I went today to charge at a "per port" station, to see how the MiEV's charging rate would look as it came out of the pause. It came out well, back to the full 3kW rate.

So the low rate after the pause sure does seem to be caused by an interaction with the ChargePoint Power Management sharing software.

I do not know why it took me so long to notice that there are two types of dual cord stations. I plan now to stay away from the "shared" stations, even though they are closer to my beaten path. I also do no know why ChargePoint customer support people have not clued me in to using "per port" stations instead.

Below is a picture of this morning's station display, showing that even though it is a dual cord station, it does not say "shared" in the orange text near the upper right. Below that is this morning's trace showing that the rate is 3kW even after the pause.

 

[JoeS]

Great observation that we can tell what type of dual-port ChargePoint station that is! I'll be watching for that.

Your charge taper graph shows an unusually-long taper that goes quite low and keeps going. Mine cuts off abruptly at around 0.5kW and lasts about one hour. The graph below was taken seven years ago: the red line represents only one leg of the 240vac and the green line is solar production.

 

[kevin1956murray]

I too had noticed that Tuesday's taper was quite shallow and long. I know that because I was sitting by the car in Texas heat, waiting for it to finish, in hopes of seeing exactly what the station display would show. I finally gave up.

Yesterday's taper looked more like your graph (as I was monitoring the trace on the app), but now it is more condensed since I did not get back to the fully charged car in a timely fashion. (Graph below.)

Anyway, I'll be watching that, by looking for a taper that is about an hour long, on a station that I know is pushing 240V.

 

[kevin1956murray]

Below is today's charge, showing what looks like a normal (not shallow) end taper. So I'm thinking my old MiEV is still OK.

I am not sure why that end taper was so shallow the other day. It could be because of the throttling of the "shared" line, even though no other car was plugged in. Or it could have been the result of me pressing the release button near the end, as an experiment to see if the trace would glitch upwards.

 

[kevin1956murray]

I have just realized that the ChargePoint website indicates a "shared" station in the 'more info' popup, by turning a little wishbone icon (lower right of the popup box) blue.

The Parmer station shown just below is shared, where as the Nordstrom station screenshot below that is not shared (the 'wishbone' split wye is very faint).

The app shows it too, but in a different way. Shared stations say "shared" at the 'Start Charge' page. (Unshared stations do not say shared.)

 

[kevin1956murray]

Below is Chargepoint's analysis and response to my request that they fix the shared stations so that my MiEV will return to 3kW after the pause, like it does on no-shared stations. Bottom line: The problem is not fixed.

Chargepoint's email to me:

Hi Kevin,

Thank you for your eagerness to help on this! However at this time I believe we have all of the information that we need.

To preface, when your car is plugged into a Level 2 station (J1772 protocol), it "communicates" with the station by putting the pilot into one of six states. This is a simple analog signal, but it allows the station to know what the car is doing.

After some research into the logs, I've found what seems to be the cause. Typically, a car stays in State C (charging) until its battery management system determines that the battery is full and stops charging, moving to State B (Detected, not charging). Even for cars that take a pause, they typically move to State B during the pause, but them move back to State C when they start charging again.

As for your session, when your car pauses, it stays in State C while drawing a very small current. Our station reads this as the car telling it that it is about to be fully charged, and therefore the circuit sharing stations limit the draw to 6A and allocates the rest to the other port as it assumes that the car is "ramping down" to finish it's charge. If the car went to State B during the pause, then back to State C when it resumed, you would get the full current allocated again. This is what happened when you pushed the proximity switch in the handle by pressing the thumb tab. It fully cut the current to the car (the car moved to State B), then allowed the full draw afterward.

​

At this time, the only workaround is to not charge at power shared stations. We are investigating when and if this change can be implemented on our stations. That being said, I can't quote a time frame for the change to be implemented.

I apologize that there is no immediate fix, however I want to reiterate my appreciation for your help investigating this. Should you have any questions, please do not hesitate to let me know.
Have a great day!
Kasey Smith
Manager, Owner and Partner Support
Direct: 480-291-5381
ChargePoint | chargepoint.com | 877-850-4562

 

[coulomb]

Below is Chargepoint's analysis...

Brilliant! It's more or less as we suspected; the car does something unusual but (as far as I can tell) perfectly legitimate, and the EVSE makes an invalid assumption (must be ramping down), and doesn't test that assumption later (is it drawing more current now? Oh, maybe I should recalculate the sharing).

So: a fix could come from either side. Mitsubishi could change the charrger firmware to move to state B when pausing (open the relay that is holding the 1.3k resistor to ground on the pilot signal after the diode), or ChargePoint could check if the car is drawing more current than expected, and if so, recalculate the sharing. Or just recalculate the sharing every 1-5 minutes anyway; things may have changed.

Who will finish first, the tortoise or the snail?

 

[JoeS]

kevin1956murray, thank you very much for the update. I just noticed that you had not retrieved my 5 September PM to you about this, as I still have not followed-up and performed the test. I gather it is now not so urgent as you've identified which dual ChargePoint stations actually share a common input vs. having a separate input to each plug.

coulomb, love the tortoise or snail analogy!

I'm not aware of any other EV actually performing this 'timeout' function. Hmmm, I wonder if it's in the charger programming or elsewhere? kiev, does your brand-new OBC still do this?

 

[kiev]

Joe, i really don't recall ever seeing this delay on either of my cars, before or after the new OBC. So i have a hard time understanding what is causing this to occur...?

 

[kevin1956murray]

I filed an online request to Mitsubishi, pointing out that Chargepoint seems to not respond well to the MiEV pause, and I asked for a possible update so that charging would return to 3kW even after the pause on shared Chargepoint stations. Below is Mitsubishi's response, which (except for the first sentence or two) seems like a pre-packaged response.

From Mitsubishi:

[email protected]
Wed 10/9/2019 11:14 AM
Dear Kevin Murray:



Thank you for providing Mitsubishi Motors North America, Inc. (“MMNA”) the opportunity to review and address the concerns regarding your 2012 Mitsubishi i-MiEV , VIN: JA3215H13CU0_XXXXX. Unfortunately, we are unable to produce a software update as requested in your email.

As stated in the Owner’s Manual:

Section 1 page 19:

Repeatedly performing only quick charging (if so equipped) can reduce the battery capacity. Regular charging is recommended unless quick charging is necessary.

To help maintain the capacity of the main drive lithium-ion battery, the following is recommended.

Do not repeat charging when the main drive lithium-ion battery is at or near the full charge.

It is recommended that you perform regular charging from 2 bars or less on the energy level gauge to full at least every three months. This lets the energy level gauge adjust to decreases in battery capacity and correctly show the remaining energy in the main drive lithium-ion battery.

Section 1 page 40:

Charging is designed to stop when the main drive lithium-ion battery capacity reaches 80%.

Section 1 page 37:

Charging may stop before full charge. This is a control for efficient charge and not a malfunction.

You can also review your Owner's Manual online by registering your vehicle with us online at www.mitsubishicars.com by selecting Owners then Sign Up or click here. You may be assured that we welcome constructive suggestions from individuals such as yourself. Careful consideration of the impressions and recommendations (from our consumers), play a vital role in our efforts to improve our vehicles. MMNA recognizes the needs and demands (of the buying public) must be met, to be successful in today’s market and we do understand the significance and importance of considering the thoughts of vehicle buyers.

Thank you for taking the time to let us know how you feel about our products. We truly appreciate your interest in Mitsubishi vehicles.

Thank you, again for contacting Mitsubishi Motors.

Best Regards,

Customer Relations
Mitsubishi Motors North America
P.O. Box 6400
Cypress, CA 90630
Phone: (888) 648 7820
Fax: (714) 934 3524

You may also find answers to your questions online at http://www.mitsubishicars.com. Just click on Owners, and then Support.