Uh Oh... Clarity Charge is Chattering !

Discussion in 'Clarity' started by MrFixit, Jun 16, 2022.

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  1. MrFixit

    MrFixit Well-Known Member

    I have had the Clarity for a little over 3 1/2 years now. It has been charged 637 times (full and partial). The vehicle has been (and continues to be) completely trouble free. The charging port has never been touched by any EVSE other than the home setup with a L2 JuiceBox 32 Pro (and a couple times with the OEM EVSE right after purchase).

    But - Now I am seeing something very weird.

    The Juicebox 32 Pro is a smart EVSE with WiFi and it logs charging energy. Here is a normal charge cycle:


    This plot shows a cycle which is nearly a full charge (~12 kWh) over a ~2 hour period. The top curve is the input power (right axis) which runs at a very steady 7.2 kW. The bottom curve shows the accumulated input energy (kWh) which increases linearly until the charge is complete. During the final 10 minutes or-so, the input power tapers down slowly (we have postulated this is cell balancing).

    I normally do not pay much attention to this, but two times recently, charging abruptly stopped for around 2 minutes, then started up again with no intervention on my part. When I saw this, I looked back at the charge logs and found some very odd looking curves (which seem to be getting worse).

    Here is a charge cycle from yesterday:


    Note, this charge shows some pretty severe 'chattering'. The input power starts at the normal 7.2 kW, but then it steps down to 6.7 kW, then promptly begins 'chattering' between 6.7 and 5.9 kW. About half way through the charge, it abruptly terminates and re-starts a couple minutes later. After re-starting, the charge continues to 'chatter' and eventually completes. I did nothing to re-start the charge, it all just happened on it's own. The total input for this cycle was 13 kWh which is quite normal for a full charge. While this was happening, I was watching the line input (reported by the JuiceBox) and it was very steady at 245V the entire time.

    Just to get a better feel for this, I looked back through the JuiceBox logs. In the last 6 months, I have charged a total of 70 times. Prior to 5/29/22 (59 charges) they all looked 'normal' except for 2 of them (1/29 and 2/15). Since 5/29 (11 charges) they all looked bad (except for one of them). This seems to indicate that this is getting worse.

    Once again, I have seen no ill-effects with the operation of the vehicle. I would not have even known about this without having the smart charger logs to review, and being suspicious because of the two recent 'dropouts'.

    My opinion is that this is not an EVSE issue. The EVSE just applies the line voltage, and the vehicle controls the current that is used. The fact that the line voltage was solid makes me suspect that the Clarity is chattering / varying the current drawn.

    Is there anyone out there with a smart chager who can look back through their logs to see if this is happening to them?
    Madmartigen and ClarityDoc like this.
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  3. ClarityDoc

    ClarityDoc Active Member

    Given the consistency of the change, it might be tempting to charge with a different EVSE. While I don't know the internals, one can imagine a failing connector/component in either the EVSE or the car's charger. Of course, it'll be most informative if you can find someone with an EVSE that has similar logging. Alternatively, if you get a consistently full charge with another less informative EVSE that might still suggest an issue with your EVSE.
  4. Robert_Alabama

    Robert_Alabama Well-Known Member

    If you have access to a chargepoint public charging station, you can set up a chargepoint account and see the charging on a graph. The time intervals are about 5 minutes, but it may give you an idea. Here's a photo of my Clarity charging today.

    JFon101231 likes this.
  5. insightman

    insightman Well-Known Member Subscriber

    I wondered what JuiceBox would say. Then I realized I didn't know if the company was actually called JuiceBox. Here's what I got from Google (NSFW):

    Who is JuiceBox?

    Brianna Rader wants to help you have better sex. Her app, Juicebox, enables anonymous users of all gender and sexual identities to receive text-based sexual wellness tips as well as personalized one-on-one coaching. Jun 26, 2019
    JustAnotherPoorDriver likes this.
  6. JFon101231

    JFon101231 Active Member

    Lol maybe add EVSE to that search
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  8. MrFixit

    MrFixit Well-Known Member

    Yikes !
  9. NorCalPete

    NorCalPete Member

    I have used a JuiceBox 40 since January 2019 (purchased base Clarity on December 26th). I have seen similar patterns, including our last charge session on 6/12 (see attachment). This has happened sporadically since we got the EVSE. I've been assuming that the car is using power to do something (e.g., heat or cool the batteries) during the charge session. A more extreme pattern of "chatter" occurs when we use remote climate control to pre-heat or pre-cool the car. Most times, the charge patterns are smooth ones (i.e., without chatter).

    Attached Files:

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  10. MrFixit

    MrFixit Well-Known Member

    Thanks for the report. Your suspicion about the car using power to do something is quite plausible.

    I probably would not have raised this issue at all if not for the complete dropouts (roughly 2 minutes long) that I experienced with recent charges.
    In your experience, have you also observed dropouts during a charge?

    Also, my impression that this has gotten worse could be related to the fact that we are entering summer and there is more of a need for auxiliary cooling during a charge...
    Madmartigen likes this.
  11. insightman

    insightman Well-Known Member Subscriber

    The never-ending revelations of new mysteries regarding the Clarity's operation make this such an interesting forum! Here we are discussing a phenomenon that could be a design feature, a seldom-noticed but harmless bug, or a component failure.

    I always wished for a tell-all book by the designers of Honda's first hybrid, the gen-1 Insight, but such a book about the Clarity PHEV would be much more interesting. "And then we had to decide how to cope with the potential for overheating while charging. Should we increase the power-draw from the EVSE to operate the fan while charging or should we alternate charging and fan operation? The alternation approach would provide some time for the battery to cool off, but it would extend the time required to achieve a full charge. Refer to Chapter 7 where we discuss our priorities for charging speed versus protection of the traction battery."
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  13. NorCalPete

    NorCalPete Member

    I don't see any dropouts in my data. Given how finicky the Clarity is about it's charging source (as reported by others when using public chargers), maybe your area experienced brownouts at those particular times. I charge almost exclusively from 12:00-2:00am (due to time-of-use billing), so I'm not likely to experience brownouts while charging.
  14. Teslawannabe

    Teslawannabe Active Member

    Hello MrFixit, to add my two cents worth. I don't have any data from my EVSE to share but I have very sensitive LED lights in the house. I have noticed the result of what I believe to be the same concern with my 2018 Clarity while charging. My LED's will flicker quickly usually one session during a charge and I has been the same with two different EVSE's, so seems to be a Clarity thing. I have had no issues related to charging.
  15. megreyhair

    megreyhair Active Member

    Maybe the batt is getting too hot and it slowed down or stopped charging completely so the batt can cool down? The fan does kick in from time to time to cool the coolant but I believe most of us have our Clara's in the garage where there is no ventilation and the ambient temp can get high enough to reduce cooling efficiency.
  16. zman0900

    zman0900 New Member

    My chargepoint graphs are not nearly as detailed as yours, but I do notice some waviness sometimes. Seems more common when it's warmer. I don't think my graphs would show any drop outs unless it lasted for at least 10 minutes or so. But there was one time where I heard strange noises from the garage and went out there to find the charger repeatedly clicking on and off, switching about every 2 seconds. That was at a time when the Honda link app had been particularly bad, so I assumed it was caused by that sending garbage commands.
  17. MrFixit

    MrFixit Well-Known Member

    I just came upon an old thread (2019) that was started by @jdonalds.
    He had this exact same phenomena with his Clarity and went to some great lengths to try and resolve it.

    Here is that thread:

    @jdonalds - You were was seeing this same 'chattering' charging current, but were also concerned about range reduction at the time. You attempted to resolve the abnormal charging curves by contacting both Honda and Juicebox (to no avail). As best I can interpret your old thread, the odd looking charging curves seemed to have disappeared on its own for no apparent reason? Are you still watching this? Are your charging curves 'normal' or do they still show this odd behavior?

    Mine has been doing this 'chattering' consistently for about a month. Prior to that, I had ~3.5 years (600+ charges) without any of this odd chattering. As I mentioned above, I have seem no ill effects with vehicle operation. I believe it charges to 100% and I see no ill-effects with range. It may take a few more minutes to charge because the input averages less than the normal 7.2 kW when this is happening.
  18. Charged_Up

    Charged_Up New Member

    Like Mr. Fixit I have a plug in Juice Box 40amp. When I bought mine it came with a rebate that covered almost all the cost of the unit. I also gave my power company the ability to trim charging rates during peak usage periods.

    I also have the chatter on my charging graphs. Seems to be related to heat both ambient and of the battery pack. I noticed that in the spring I could charge at 7kw with no chatter. As the summer progressed I saw the chatter. I reduced the charge rate to 16amps on the JuiceBox and the chatter disappeared.

    I don’t think it’s a defect in either the JuiceBox or the Clarity. But I am curious to see how it goes as the temp falls.

    Sent from my iPhone using Inside EVs
  19. MrFixit

    MrFixit Well-Known Member

    I was about to post a follow-up here. I appreciate your input.

    I too discovered that reducing the maximum current setting eliminates the chattering. I worked with this for a while, and spent some time adjusting the current. I found that I got chattering with the default (in my case, 32A) and also at 30, 29, and 28A. When I went down to 27A I have seen no more chattering so far.

    I agree that this is unlikely to be a 'problem' with either the vehicle or the Juicebox. It is just SO strange that I never had ANY chattering until around June of this year. I could look back at my entire history (all the way back to November 2018) and there was never any chattering. I have a total of over 700 charge cycles to date.

    I will plan to leave mine set to 27A. This has only a trivial impact on charging time, and I just feel better when this is not happening. I will continue to keep an eye on it.
  20. Charged_Up

    Charged_Up New Member

    First off I’ve been reading the forum since before I bought the car in 2019. I bought and use your OBDii setup and was blown away that you got the car scanner software people to include Clairty as a covered vehicle.

    I must have different firmware in my JuiceBox because I can’t specify exactly a charge rate but I just reset mine to 24A. I will let you know if I have any issues.

    Again thanks got your huge contribution to the Clairty community.

    Sent from my iPhone using Inside EVs
  21. MrFixit

    MrFixit Well-Known Member

    I'm trying to understand why you seem to see different options than I do. FYI, I access my JuiceBox from my laptop using the web-based interface at https://home.juice.net/Portal. When I view my juicebox device there, I have this screen (note the section that I circled in red that shows the current setting):

  22. Charged_Up

    Charged_Up New Member

    I use the EV JuiceNet app on my smartphone (ios) to access my charger. It has a drop down menu to chose charge rates.

    I’ve never used a browser to access but I’ll have to give it a try. BTW just finished a 10Kw charge with no chatter.
  23. MrFixit

    MrFixit Well-Known Member

    FYI - While investigating this, I found that the Clarity seems to draw slightly less than the 'limit' set by the EVSE (roughly 1 amp less).

    ie: when the EVSE is set for a 27A maximum, the Clarity draws closer to 26A. It is possible this is intentional because of measurement tolerances to insure that there is some safety margin to stay within limits.

    I was curious about this and actually measured the pilot signal from the EVSE with an oscilloscope. I found that the JuiceBox pilot was spot-on, and when the limit is set to a particular current, the pilot very accurately reflects that. Thus any deviation is (not surprisingly) due to the vehicle's charging system.

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