12V battery

Might be worth a look.

Right. But maybe the car only checks for ground at the start of ABS.

And just to note, ABS stopped early when HV charging finished.

 

Yes, an ABS by itself should be around 15-20 min and so it's hard to be certain how plugging in the EVSE and the very short HV battery charge event affected this. An HV battery charge event initiates its own equivalent to the ABS, just as Run mode does. So, we really don't know why the ABS terminated. Might be better to let things play out one at a time so you have good data.

We don't know what the car does prior to an ABS event. But there seems to something about one of your EVSEs being plugged in that upsets it and the main difference is that the EVSE connects the car chassis to the ground as defined by your house wiring.

Well, if it isn't that, you'd have to wonder what else it could be?

 

We do know when the ABS terminated - simultaneously with the HV charge finishing. Recall that the EVSE was plugged in after ABS started. Possibly the HV termination caused the car to check the ground again. This time it would have seen the problem we hypothesize and terminated ABS.

Today (bottom graph) nothing happened at 13:56. But it might have tried to run ABS a little after 7 am. Recall that the full graph didn't capture the spike seen in the short term graph two days ago.



Later this afternoon I will move the EVSE from the subpanel 120v outlet to the main panel 120v outlet.

 

I would have thought that the scheduled ABS on 4/9 would have started at 1415 hours but your second graph stops at 1400.

 

I left too early. It did try and fail to start around then - probably 1409, the time it terminated early the previous day.



Disappointing today - plugged into 120v house circuit and again failed to run ABS.

What do you think about running a ground wire from the car chassis or -12v to the subpanel case, which is connected to the circuit ground wire?

 

Just catching up with this thread and comparing your findings against what I observed on my KIA Niro EV. Pretty much the same behavior as the Kona. I've already had the 12V battery replaced under warranty after only 6 months (all my ICE cars required new batteries every 5 years) so trying to understand what the purpose of the Battery Saver function actually is. Taking some voltage readings and looking at your data to confirm, I see that it starts every 24-hours since the end of the previous run and always runs for exactly 20 minutes. That seems like a strange design to me. Why wouldn't it be triggered on a threshold minimum voltage instead of relying on some arbitrary fixed timer schedule? Also why exactly 20 minutes? On my car, those entire 20 minutes are spent on maximum 14.7-15V charging voltage and after the charge completes I'm left with a slightly lower battery voltage than I had when the charging completed the previous day. As a result, if I leave the car parked and unused, the 12V battery voltage will slowly decrease over the course of many days, despite the 24-hour, 20-minute charging cycles.

Is there any evidence that the Battery Saver would actually "save" your battery if the 12V battery voltage dropped below a certain minimum level before the next 24-hour charge cycle starts? Has anyone tried attaching a high wattage variable resistor inline and dropping the battery voltage to see what happens with a parked car?

On my Chevrolet Bolt, the 12V battery charging is automatically triggered when the car detects voltage below 12.1V and runs as long as it takes to recharge the battery (not some fixed 20 minute cutoff). It checks the voltage every 6 hours. There are also various other protection mechanisms to detect abnormal current drain and perform 12V battery maintenance to prevent sulfation and extend service life of the battery. Not sure what these KIA/Hyundai cars offer in comparison but you can read about the Bolt from the service manual quoted here.

 

Just to catch up, was that last ABS failure with an EVSE connected? We need to be sure the car by itself is working properly.

In general, assuming that the Kona without any EVSE connected can carry out a daily ABS reliably, my opinion is that the issue revolves entirely around the impedance of the ground connections pertinent to your EVSEs. By that I mean that it seems to be a long wire and may have some poor terminations along the way. The ideal situation is that the ground is provided directly from a ground rod or steel water supply pipe close to or within the garage so that it more easy passes whatever tests the EVSEs and car are applying. You might need to have an electrician look at this.

 

There's been no evidence that it can detect a low voltage and plenty of anecdotal evidence that it can't, however I'm also pretty sure no one's tested that formally. There is also no reason to believe the eNiro is any different from the Kona EV in aux battery management.
I think we're not trying to justify the design we are stuck with or compare it with others, just trying to characterise it in detail so we understand what is going wrong when it fails and how we might avoid that.

 

If the ABS never triggers when voltage drops to dangerous levels, then it's probably a legacy design limitation from the ICE versions of these cars. On an ICE, there would be no reason to monitor the 12V battery when the engine is off since there would be nothing you could do about it. Most likely whatever controller can read the voltage is only powered when the car is in the "on" state (or charging). The 20-minute/24-hour cycle thing looks like a simple timer they stuck in there at the last minute as a band-aid.

I noticed when my Niro is doing its automatic 20-minute charge, the instrument cluster LCD screen behind the steering wheel is illuminated (just shows black screen with P gear and mileage). So at least during this state, some computer is operational and should be able to read the 12V battery SOC and voltage and extend that ABS charging session beyond 20-minutes if required. Does the Kona also turn on the instrument cluster while doing ABS?

 

Yes. And today, plugged into the subpanel 120v, with a wire running from the car chassis to the subpanel ground, it again started to run ABS and failed.

That's what it looks like. Although it is possible that something in the Kona is making it unduly sensitive to the ground or to the presence of an EVSE. I didn't have any problems for the first month of ownership, then one dead battery Feb. 17, then solid failures starting March 14. So what changed - the ground connection or something in the car?

One more piece of data. We went on a 150 mile trip March 10, charged on a 240v EVSE there, and returned March 12. This was the first time the SOC went below 50%. Probably just a coincidence but thought I'd mention it.

@wizziwig, I'm also coming from a GM platform (2nd gen Volt), and the nicest way I could put it is that from owning the Kona and reading the forums, my sense of the engineering in the Hyundai/Kia EVs is that it is not as robust as GM's.

 

Yes it does. The voltage during charging is not going to be terribly useful since it's regulated to 14.65 V (approx, provided the current limit is not exceeded, which does happen if the charge level is low). What it could do during charge is to monitor the charge current to determine if it's flattening off. But, you'll notice Toolworker's charge time in minutes is much the same as mine, yet his initial voltage is about 0.4V lower.
It's a fair deduction that the car cannot assess the battery state without waking up and we know from voltage logging that, left alone, it only wakes up for the scheduled ABS event. It's unfortunately also appearing that it doesn't compensate for abnormal quesent loads (Hyundai calls it "black box" loads) or a lower starting voltage.

There was however a sliver of evidence that it assesses aux battery health while driving by applying a charge and subsequent discharge of equal energy, just witnessed once on my car and documented here some time back. Whatever that accomplishes has yet to be determined.
The LDC can measure unloaded battery voltage anytime while "on", simply by regulating system voltage based on zero aux current battery, a mode it operates in the majority of the time while driving and during traction battery charging after the initial obligatory short aux charge event.

 

At 14:02 today it tried and failed again to run ABS. The OEM EVSE was plugged into an extension cord to the neighbor's 120v outlet. The pattern was similar but not identical to Friday's.



I will leave it unplugged tomorrow and expect it to run ABS normally.

So to summarize, it has now failed identically on the OEM EVSE on my 240v and 120v on the subpanel, my 120v on the main house wiring, and my neighbor's 120v. It fails, but differently, on the AeroVironment EVSE.

Are we ready to shift to the hypothesis that the fault is in the car?

 

I had a look through the partial Kona service info I have and the LDC functions are not included. The only leakage function that seems to be present on the car is that checking HV battery to chassis.
I also verified that my portable EVSE senses ground by driving 0.3mA to ground from the AC line and expects the presence of that flow from at least one side of the line on a continuous basis. That would handle both L1,L2 or L,N wiring situations but it's hardly going to detect insufficient ground current-carrying capacity.

Perhaps it's time to revisit the dealer since there are no diagnostics we can do on the car, that I'm aware of. There seem to be two errors, that of the scheduled ABS failing with an EVSE connected and that where the wall EVSE fails to start. Even though common sense says they are likely related to the same root cause, it's probably best to let the technician come to that conclusion.

 

As expected, the vehicle ran a full ABS a little after 14:00 this afternoon. It was not plugged into an EVSE.

Now I will document this and email to the service advisor, in the hope that her tech will say something more useful than "Bring it in and let me look at it again."

 

Voltage tends to drop very quickly just after completing a charge so I wouldn't measure it then - wait at least 15 minutes. I usually track the voltage in the middle of the 24-hour cycle to see how it drifts over multiple days. Interestingly, after about a week left parked and unplugged, my 12V in the middle of the 24-hour cycle seems to have stabilized around 12.8V each day. So either the car has gone into a deeper sleep of some sort or my earlier observations of small daily declines were caused by ambient temperature differences?

Has anyone graphed what happens to current during the 20 minute charge cycles on a battery after it's been sitting for a few days? I've only been tracking voltage because I don't currently have access to a clamp meter while under lockdown.

 

They should be able to prove the fault on their in-shop AC EVSE if left for a sufficient period. Or they can use your portable unit.

Check post #73

 

Depends on what they recognize as a fault. Will they repair the car for not running ABS on the Hyundai EVSE?

Or do I have to bring them my EVSE so they can see it kill the 12v battery? And if I do, don't you think they will just blame the EVSE?

Thinking positively, I'm hoping that my graphs and videos will be enough documentation for them to recognize the problem, and that it might be familiar to the tech, or to his support engineers at Hyundai.

And now that we're all staying at home, I won't leave my car at the dealer and get a rental car. Now that I know to keep the EVSE unplugged when not charging, the 12v battery will rarely die. When it does, I can start the car with my handy little jump pack at the cost of a couple of minutes. So I'll try to get the tech a jump start on the problem, but if it has to wait until things are closer to normal, so be it.

 

Was hoping someone measured current directly using clamp meter to confirm accuracy. That way you're not introducing variables by also powering the OBD2 port and adapter. Also, that port seems dead on my Niro when car if powered off and the Aux Bat Current always returns a garbage value regardless. I think the pids must be wrong because I tried playing with the formula and still couldn't come up with anything sensible for the Niro. The tweaked Kona formula posted somewhere on this forum didn't work on the Niro.