12V battery

I agree. I will annotate the chart next time. The monitor is wireless, so it is logging the voltage all the time when the car is at home.

 

I'm new to the forum but not this problem. The pattern we have seen is that the 12v battery dies after a full charging cycle

• We plug in the car to charge overnight
• Charging is delayed by charging schedule until 10PM
• Car charges fully (or, more recently, to 80% limit).
• Dead 12v battery in the morning when go out to the car.

This is not reproducible - it has only happened a few times.
Charger is JuiceBox - charges at 40kW
Car is in garage - no unusual temperatures.
The past couple of times with have received the following message on our BlueLink phone app: "Your vehicle is not charging. Please try again. Ensure the vehicle ignition is OFF and gear shift is in PARK." This is 20 - 200 minutes after the charging completed message. This is the only circumstance where we have seen this message.

I now keep a jumpstart battery in the trunk and a 12v charger mounted on the wall next to the front of the car in the garage. I also have a 12v car voltmeter plugged into the accessory outlet. I try to remember to check the voltage by turning on accessory mode before starting the car. So far we have not seen any other circumstances that cause the dead battery.

 

Welcome, @Otter .

I have the same problem with a 40 amp Aerovironment EVSE, which is JuiceNet enabled, so may be similar inside to yours. From time to time it gets into a death spiral where the Kona tries to charge the 12v battery, that triggers an interchange with the EVSE, that aborts the 12v charge and drains the battery a bit. And repeat. This drains the battery over a few hours.

If you look back in this long thread, there's a video of this loop in action, and several graphs.

The precise loop only occurs with the Aerovironment EVSE, but having the included Hyundai EVSE plugged in also occasionally disrupts the 12v charging. I ran an extension cord from my neighbor to rule out a problem with my house wiring.

I'd suggest you open a case with Hyundai Customer Care. The more complaints they get, the more chance they will actually look for this problem. Depending on your state's lemon law, you may want to document this, and when and if when you have the time and inclination, call Hyundai Roadside Service to do the jump and document that. In any event, put it on the service order whenever you go in for one of the recalls.

And I have learned to plug in the EVSE only when I need to charge (or want to try to make the problem happen again).

 

My wife inadvertently forgot to double check closing the rear hatch yesterday afternoon and, when I checked the BM2 this morning, sure enough the normal recharge heartbeat had been suspended.

Every four (+/-) hours was the battery drain event without the overlying recharge event.

Closing the hatch this morning returned the recharge heartbeat back on.

So, with the latest software updates, the battery tender software still gets fouled up with an improperly closed rear hatch.

 

I'm sure Hyundai's engineers have a good reason for these elaborate algorithms (maybe job security?). But why doesn't the car just watch the 12v battery and charge it up whenever it gets below 50% or so, like any $30 battery charger would do?

 

If a procedure exists, I will consider it

 

Yes, that thought had occurred to me as well but I suspect it would harder than it seems because of the control logic still needed between the switch and the electric latch actuator.

Can you post the BM-2 graph of all that?

 

In screen shot one (above), you can see the normal "parade pattern" every four hours (at 0140, 0600, 0950 (interrupted with use of the vehicle)) and then they disappear after 1100...



In screen shot two (above), the normal "parade pattern" returns after I discovered and correctly closed the tailgate at 0545.

 

This might help, EE. It's fooling the IPS Control Module firmware that's the concern.
But experimentation with the two switch conditions might lead to a suitable solution.

 

It's interesting that after 19 hours of tailgate ajar the battery is not badly depleted at 12.5 V and did not continue to deteriorate. And, that a single aux charge event was enough to restore the voltage to better than it was before.

 

That tailgate switch initiates more than interrupting the 12V battery charging. I once set off on a short trip with the tailgate not completely shut (the red open indicator was showing). Soon (after about 100 metres) an intermittent alarm sounded but I decided since it was a short journey just to carry on. However in about 1 km I stopped at a pedestrian crossing and the car would not move again. So out I got and shut the tailgate and was able to get going again.

 

Here we go again.

Having given up on Hyundai ever fixing my 2020 Ultimate's recurring dead 12v battery, I jumped at the chance for a lemon law buyback. I'm not sure they were clear about which battery was my issue, but either way, I qualified.

After taking a hard look at the available alternatives this past June, I replaced it with a 2021 Ultimate. I figured at least I'd get rid of the intermittent 12v problem.

And I was right, sort of. After three months, the problem is back, with a slightly different look. But it's no longer intermittent.

Things were going along pretty well. It died the first morning after I got it home, but after that it was solid. A typical day unplugged:



Then it quit charging the 12v battery. But it wasn't going dead either. (This graph is a full week.)



But then it picked up another bad habit. It looks like something is waking the car up three or four times an hour, from midnight until some time past noon. Since it no longer does the battery management charges, that eventually drains the battery.



It's been doing this for almost two weeks. Here's a full week:



With the 2020 I suspected an interaction with the EVSE. But this car was unplugged for the whole week shown above, except from 5 am to 9 am on the morning of 9/23.

I wonder if it has anything to do with the charging schedule. It's set to charge from 11 pm to noon. It goes weird around an hour after 11 pm, and usually recovers its sanity from 1 to 5 hours after noon. I'll turn the timed charging off and see what happens.

The good news is, if it stays solid like this, I can leave it at the dealer (the one that never has loaners available) and it will eventually die. The bad news is that they will just replace the 12v battery, do all the updates (the car was built in December 2020) and hand it back. That never fixed anything before, but there's always a first time.

 

Hmm, what a pain in the butt. In general all I can think of is:

1. We know an open hatch cover disables periodic 12V charging. All door switches appear OK?
2. We know the traction battery monitoring is on a 1/2 hour schedule and although it has a similar characteristic squiggle, it's usually only active after driving or traction charging, neither situation being what you have here.
3. Because I don't have this feature, I don't know how the telematics affects 12V drain and if it can disable periodic 12V charging.

Any cell towers nearby, lol?

I only just realised after what, 2 years, that the BM2 voltage scale is annoyingly non-linear, 9---11-12-13---15.

 

BINGO!

Remember WeaveGrid's post seeking help with a program to sync utility loads with EV charging? I gave them access to my telemetering right around midday September 20.

And look what happened:



I think they owe me another Amazon gift card. Probably you too!

Edit: I don't think the telemetry necessarily disabled 12v charging. It's been topping off almost every day from Sept. 28 on. More likely it was Hyundai's creative charging algorithms, which are why this is the 377th post in this discussion. My 2021 was built in December 2020, so might be several algorithms behind the times.

 

It's confirmed that these wakeup calls are from WaveGrid pinging the telemetry.

Does anyone know what amps the car draws when it wakes up to handle a call, and how long it stays on before going back to sleep? It doesn't look like it's on for very long. [Edit: I can check this with the 5 minute graph on the battery monitor app.]



Does it make sense that waking the car up about 100 times is enough to pull the battery down from 12.6v to 12.0v, even with the charging algorithm sulking?

 

Well, yes.

Torque Pro was able to link with the OBD-II while this monitoring was going on. It displayed the 12v voltage constantly, but the 12v current only when something was going on.



It showed a 6A draw for about three minutes. 100 times that is 30 Ah, or about 2/3 the capacity of the battery.

Updating the BlueLink app does the same thing. I updated the app's home screen every 15 minutes to simulate WaveLink's polling, and got the same voltage graph as the ones above.

This would all be academic if the Kona could be relied upon to recharge the 12v battery when necessary.