12V battery

The difference between your graphs and mine is that your wakeup activity seems to give up after 3 hours, while mine continues for the full 13 hour off-peak charging period, and your battery voltage appears to stay above about 12.7 - 12.8v while mine drops down to 12.5v and sometimes close to 12.0.

Didn't have to do that anyway. The cover was always sitting on that flat metal shelf down below the battery, even if I'd driven since dropping it.

And I'd rather have the sensor on the terminal protected against splashing.

 

I've finally witnessed the ABS changing from the 4-hourly to the daily schedule after the car is parked for a few days. That time period appears to be 60 hours.
This doesn't seem to be related with the fact that occasionally during the 4-hourly schedule it sometimes skips one, or even more in a row.

 

I'm certain that any drive over 30 minutes would, but I was unsure about shorter drives or utility mode.

What appears to have happened after four short drives is that first the previously-scheduled 24-hourly ABS still triggered at 03:30, seemingly indicated that the timing was not reset, as was the case before the both BMS updates (after drives <30 min) when all ABS events were repeated at only 24-hours. But then further ABS events appear 2 and 4 hours later.

It's not clear why there's sign of a steady draw between 23:00 and 01:20. The new BMS software is certainly busier that the original.

 

Had an interesting "lesson learned" today.

I went along as self loading baggage today and, as usual whenever I interact with the Kona, I checked the BM2 app on my phone prior to departure.

Instead of the usual "blue" icon and "Battery OK" status indicators, things were red and less than 12 volts...

Here is the data for today:



The usual "heartbeat" is there, but as one can see, the system was not actually topping up the battery with each of those heartbeat events...

Yesterday:



Two days ago:



Prior to the drive event at 1055, the heartbeat was normal.

After the car returned home and was shut down at 1200, something changed and the car was no longer recharging the 12 volt battery...

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When the pilot strapped in, I told her that the "rear hatch open" warning was showing on the instrument panel...so she went and gave it a good slam shut.

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For whatever reason, if the rear hatch appears closed but isn't closed and one misses seeing the warning on the instrument panel, the 12 volt battery tending software will not allow the 12 volt battery to be topped up by the traction battery.

 

Was the car plugged into an EVSE? If so, does it behave differently when unplugged?

I have seen interaction with EVSEs that can interfere with 12v charging.

 

It was not plugged into an EVSE.

 

I confirmed today that leaving the hatch intentionally ajar at 12:20 killed off the next aux charge event due to start at 12:40. The current draw keeping the warning light illuminated on the dash certainly pulled down the battery voltage, continuing until the 1:00 ending time where it crawled back up slightly. The orange light did not illuminate during the non-event.

So, it appears you get a double whammy from leaving the hatch ajar.

As a note I'm a few weeks behind on updates (D118 and D111 not done) so there's always a small chance it's been fixed.



It picked right up again at the next interval and the aux battery recovered, 8:20 hours after the start of the prior successful event rather than the normal 8:40 had the intermediate event succeeded.

 

It's baaa...ack!

Four months since Hyundai replaced my 12v battery (not with the factory battery but with a generic that lacks a cover for the -12v terminal circuitry) and did the then-latest reprogramming, I dared to think the dead 12v battery problem was solved.

No such luck. The other day it died again, and then stopped running the automatic charge (ABS+ as was) until it died yet again.



In the second panel, it looks like it went into the familiar death spiral, trying to charge but not liking what it saw from the EVSE. Somehow it pulled itself out and the battery recovered somewhat.

Ah yes, the hatch. In the third panel, I raised the rear hatch, which did something to load the battery down to where the car wouldn't start. The EVSE was plugged in with an orange light. I unplugged the EVSE and we left in our other car. That afternoon the car would start, but still wouldn't charge the 12v battery.

Next day (fourth panel), I raised the hatch again. There was some relay chatter and it again pulled the mostly discharged battery down. This time I called Hyundai Roadside Assistance to get independent documentation of the dead battery (5.06 v) and after jumping, left it on for two hours to charge the battery. That night ABS+ resumed, did not run 4 hours later, and did run 4 hours after that.

The good news is that this will be the fourth time into the dealer for the same defect, which triggers the California Lemon Law. So perhaps I can finally get Hyundai interested in doing something that might actually fix this problem. If not - there are a lot more EV choices out there than when I shopped for this car in late 2019.

 

2 years ago shortly after I got my car my 12 volt battery died. Hyundai replaced what I believe was called the Master Control Unit. In all the posts about 12 volt issues published since then I have yet to see anyone else mention this part as a cure. Is it possible that it is your problem and is thus far undiagnosed? I suppose it's possible that it was MY problem that was misdiagnosed too! All I know is that I have never had the issue recur in the last two years. *knocking wood*

 

I can't find it. It's buried somewhere in these 52+ pages. I'm not sure I actually provided a part number. Just the name as I recall. The lengthy thread was called Dead Kona EV I believe.

 

I remember your mentioning that and was waiting for the right time to push the issue.

I got the car in January 2020. Within a couple of months we had hunkered down - we're old and didn't want to take any chances. I did go in a couple of times for a reprogramming.

Now I'm willing to get a loaner car and have what I hope is leverage in the Lemon Law. So I'm ready to push them to start replacing parts.

 

Found it! Hybrid Control Unit. EPCU

 

Hi All.
I have an almost identical problem as @Toolworker
Battery at 6V after being parked for a few days. Sometimes plugged, sometimes not, sometimes locked, sometimes unlocked.
12V battery replaced, empty after a few weeks. Sometimes it's a week between incident and sometimes months. I can't find any pattern.
Here's how my voltage looks like. I just started to monitor it so I don't have an incident recorded yet...

 

Some people may have more competent or caring service dealers than I have been able to find, but here are my suggestions:

1. Keep a journal of the times this happens.
2. If you have the time, call Hyundai Roadside Assistance to jump it, and document the visit. They didn't give me paper, but I took a photo of the tech's phone showing the battery test.
3. Get a small 12v jumper to restart when you don't have the time or inclination for #2.
4. Don't knock yourself out recording stuff. They don't care. I gave my dealer a graph of the 12v battery being taken down to zero over a few hours. I have a printed service report saying the tech showed the graphs to a factory tech (and it took a huge struggle to get to that point) and the tech said it was normal operation.
5. Open up a case with Hyundai Customer (doesn't) Care. Once you are talking to someone there, your service dealer may have access to more resources - eventually, although probably not on the first call.
6. Every time you take the car in, put this on the list of complaints. They'll test the 12v battery and tell you it's fine, or replace it, or reprogram the car, none of which will work. But you'll create a record - see #7.
   
7. Does your state have a lemon law? In California, four service visits that fail to fix a problem in the first 18 months create a presumption that it's a lemon. When you get to the point of saying "lemon law," that's the only thing I am aware of that will get Hyundai's attention.

 

It would help a lot to document the conditions pertaining to your data: is the car being driving or parked, are there any traction battery charging events, and is the voltage monitor doing its job without having to open any doors, the hood or power the car on. Does your monitor log over days and if so perhaps post several days with annotations indicating any external influences as I've mentioned.