If you've had a dead 12v battery please respond

PLEASE - Can someone in the US look at their service records and tell me if this update code is the same?

Reason I ask - As a result of my letter to the president of HMA about DST, I got assigned an Executive Case Manager. I asked her if there were any software updates on my car since it was built in December 2020. After I explained the difference between recalls, campaigns and updates, she researched it. Turns out she researched it the same way I did - by calling my Hyundai dealer.

This is typical Hyundai. They prioritize people staying in their lanes over making the resources available to help the customer.

The answer? The same as I got by calling the dealer: "Bring the car in and we'll check for updates." They'll do that by entering my VIN, right? Which they could do over the phone and save me two hours drive - but they don't.

So I gave up and made an appointment. And PLEASE - I would love the U.S. code for this update, if it's different. Otherwise they'll probably tell me to bring it into a Canadian dealer.

 

My 12v went flat for the first time this morning. My car is 38 months old and has the BMS updates associated with a main battery swap last December. It had been sitting locked in my driveway unused for about 48 hours at about 25% SOC. It would not unlock this morning with the key fob. I used the hard key to unlock, opened the hood (yay for a manual release!), disconnected the negative terminal of the 12v and connected a 12v charger. About an hour on this charger raised the voltage from 10.x to 13.x, at which point I could unlock the car with the fob and open the charging door. The main battery is now on my L2 charger, which raised the 12v to 14.x after I plugged it in. So the BMS appears to be now charging the 12v battery. Why did it not do so before, after the 12v obviously reached a critical state of charge?

Having looked through this thread, my suspicions center about Bluelink. My car came with a free 3-year subscription to Bluelink, which Hundai appears to have extended to five years. I frequently drive with the infotainment system switched off. After the car passed the three-year mark, I began to see the screen randomly start up on its own with the message "Bluelink subscription successful". This screen does not time out and the only way to make it go away is to press its 'OK' button. I rarely use Bluelink because it takes about 5 minutes to execute a command and it's easier just to walk outside and do whatever. I wonder if I should call the Bluelink phone number and ask to be disconnected. As far as I can see, the main purpose of Bluelink is for Hyundai to acquire vehicle usage data.

 

Some of us keep a small jumper pack in the car, so we're never delayed more than a couple of minutes by a dead 12v battery.

I am careful to store the pack up against the back of the rear seat on the driver's side. My other charging stuff is tucked under the trunk floor, but that doesn't do much good without 12v.

 

I know it's not our common experience to see 12v battery failures under 3 years in a ICE vehicle but I honestly think you did pretty well having your 12v battery last over 3 years in an EV. In ICE cars the alternator is pretty much always charging up the battery when the engine is running and its rare to see these batteries go into an extended discharged state without some effort. When these lead/calcium acid batteries stay in a low voltage state for any significant amount of time the cell plates start to sulphate and ultimately this is what kills them. The problem with EVs is now you have DC to DC converter and software trying to predict how and when to charge the 12 V battery based on voltage measurements and monitoring measured amps used and amps supplied. Its not perfect.

I suspect you bluelink error messages were more of a symptom of low voltage and dying battery than the actual cause of your dying battery. If you get anymore weird system errors after recharging your battery its a good indicator your battery is finished or dying. If it were me at 38 months I would just buy a new battery.

 

The car has a high voltage battery stuffed with the equivalent of over 4,000 Ah at 12v, and at the other end a poor 12v battery starving to death. Talk about systemic inequity!

So the car goes through contorted algorithms trying to guess when to charge the 12v battery. It can't just monitor the voltage every few minutes because that requires waking up, which drains the 12v battery.

All these problematic algorithms could be replaced by a monitor circuit on the 12v battery, drawing negligible current, that will wake the car up for a booster charge whenever the voltage falls below a set level. Why guess when you can know?

 

My car had a VCUC update in May 2021, but maybe not that one. Is there a way fo me to tell without calling the dealer, who is closed this weekend?

In a way that makes sense to me. I will take your advice, thanks.

 

One thing I’ve noticed & been experimenting with:

scenario 1, tried 2x - I left my car unplugged for 3-4 days, when I get back into it…I get all sorts of warning lights - there are actually no issues, but a weak 12v battery. Also noticed the Hyundai logo light shows up orange a a few times.

scenario 2, tried 4x, I leave my car plugged on 32A. Battery is always charged to what I have it set for…I have no 12v battery symptoms at all.

 

I've been looking into a lithium ion phosphate replacement. They are more expensive but aren't bricked by low voltages that would kill our lead acid batteries after a couple of 'incidents'.

They can still be bricked though. I was in my dentist's office today and he told me an interesting story. One of his friends ordered a new E-tron. It came in, friend flew down to take delivery and found an embarrassed dealer. The car had sat in transit so long that the 12v had gone completely flat and the dealer did not have its replacement in stock.

My dentist is an interesting guy. For one thing, he drives a Fisker Karma. He's a skilled racer, Porsche Cup and single seaters. He has a very complete workshop, where he works on his cars and is building an EV from scratch: Tesla power train, his own platform and his own body. Platform is about finished.

 

I did this 2 weeks ago recovering from Covid, and still found a dead battery. I've tried with doors locked and unlocked with no difference.
Died twice in 10 days, while plugged into my 32A EVSE in the garage, with car scheduled climate still activated.

 

Here's the current VCULDC software version, from my U.S. dealer:



My Kona EV was built in December 2020, and this was the only update.

I will report back when my 12v battery dies again.

 

2019, more than 3 years old, 32,000 miles. Back in the early days, my 12V battery died twice, but since the software update that lights up the yellow light on the front grill when the HV battery is charging the 12V battery, have had no issues, even when parked for 2 weeks while on vacation. I drive the car daily. Last week at the end of a work day, went out to start, a few dash lights came on momentarily, then a warning on the dash to place the key fob directly against the start button (never seen that before!) and everything went completely dead. No interior lights, no response to START button, nothing. A very quick 12V jump started everything up perfectly normal. After about a minute, I shut off the car again, then tried a restart - no issues, everything perfectly normal (and no new dead battery events in the last 4 days). My Blue Link had expired, is that related? I missed having the Blue Link features (like checking the charge level, lock/unlock, etc) so I was in the process of re-subscribing ($200 a year for lock/unlock? not really sure it is worth it, but I also get emergency notification when in an accident, so that alone can save a life...). BTW, I did change my fob battery a year ago, and since the restart a few days ago, no issues at all with the fob. But, I also have not noticed the yellow grill light go on. I used to see it every few days. Was there a software update that messed with the 12V battery charging? Yes, I have had a new HV battery 6 months/6000 miles ago. There is something going on here that I do not yet understand.

 

The business about holding the fob to the button is solely a procedure recommended for a low fob battery. That being said, since your fob is probably not low I'd suggest that the message was generated by the same glitch that momentarily lit up your dash. Sometimes it happens. I'd keep my eyes open for further occurences but it might be a one-time blip. These kinds of things have been widely reported with 12 volt battery dis/reconnction usually solving it.