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Re: ChargePoint Charging Question

Posted: Wed Jul 24, 2019 9:41 am
by 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.



Re: ChargePoint Charging Question

Posted: Wed Jul 24, 2019 10:39 pm
by 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.


Re: ChargePoint Charging Question

Posted: Thu Jul 25, 2019 4:05 am
by 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.


Re: ChargePoint Charging Question

Posted: Thu Jul 25, 2019 12:30 pm
by 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.


Re: ChargePoint Charging Question

Posted: Sun Jul 28, 2019 8:24 am
by 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.)



Re: ChargePoint Charging Question

Posted: Mon Oct 07, 2019 4:27 pm
by 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 | | 877-850-4562

Re: ChargePoint Charging Question

Posted: Tue Oct 08, 2019 2:55 am
by coulomb
kevin1956murray wrote: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? :(

Re: ChargePoint Charging Question

Posted: Tue Oct 08, 2019 10:37 am
by 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?

Re: ChargePoint Charging Question

Posted: Tue Oct 08, 2019 7:06 pm
by 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...?

Re: ChargePoint Charging Question

Posted: Wed Oct 09, 2019 9:28 am
by 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:
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 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 Just click on Owners, and then Support.