Monitor Ioniq 5 12-volt Battery with BM2 battery monitor

Discussion in 'Hyundai Ioniq 5' started by CharlesBranch, Aug 5, 2022.

To remove this ad click here.

  1. The car has been parked for about 9 days now, and so far, the 12-volt battery has not died. The first image shows the BM2 recording for the day of the trip. Just before the trip, I charged the traction battery enough to leave about 10% remaining after the trip. On the return trip, we ran into a major thunderstorm, and we had to detour off of I-65 and wait about 30 minutes. That meant that we just barely made it home with only three miles to spare. P1000319_cropLabeled.jpg The second image shows the BM2 record over the next 9 days. The voltage gradually dropped from 12.62 to 12.5, but the 12-volt battery never died. P1000314_cropLabeled.jpg There were three small negative spikes over the 9 days. The first was when I queried the status of the car. The second was when I opened the hatch the next day to unload some items, and the third I believe was when my wife opened the doors looking for a lost earring. The traction battery never tried to charge the 12-volt battery during the nine days, but the 12-volt battery voltage decreased so slowly that it never entered the vicious cycle I observed before. My assumption is that when they changed the ICCU to fix the separate slow charging problem, that also fixed the dead battery problem as well. It's not impressive that two different dealers on three different occasions never took my dead battery problem seriously, and if I had not subsequently had a separate problem, my guess is that they never would have fixed it.

    I had previously criticized the apparent decision of the design engineers not to use the traction battery to recharge the 12-volt battery when the traction battery was below a certain value (probably about 20%). Now that it looks like the dead 12-volt batteries were the result of excessive drain, I am a little less critical of that design decision. Although I am now less critical of the design engineers, I am still very critical of the three service teams who refused to pay attention to the recordings I gave them and refused to even contact Hyundai to see if someone with more expertise might have a suggestion. Had they done so, I suspect that a competent engineer would have quickly seen that there really was a problem. And I am still critical of the Hyundai customer service people, who also refused to address the problem and just referred me back to the dealer, who had already demonstrated that they were not competent to diagnose the problem.

    I'm looking forward to resuming use of the car, which I really love to drive. For the last 9 days, I have been driving my old Honda Element, which has been a great car with not a single mechanical problem. But my wife will still refuse to drive the Hyundai. She still calls it a lemon, and I can't really fault her for that.
  2. To remove this ad click here.

  3. januszgrabon

    januszgrabon Member

  4. Mike384p

    Mike384p New Member

    I want to report a positive outcome on the 12 volt batter parasitic drain problem on my Ioniq 5. The bottom line: the dealer replaced the AVN head unit and performed recall updates on the ICCU. This has completely changed the BM2 profiles. Previously there were 3-4 short duration voltage drops per hour that would eventually drain the 12v battery. In order to keep the battery charged I installed a "battery tender" (small battery charger) and tried to drive or charge the traction battery every day. After the repair/updates the short term voltage drops occur about twice/day instead of 3/hour. I left the car for 4 days without charging or driving and the battery went from 13.14 volts to 12.78 volts. So, I think the problem is resolved!

    As an aside, it took about two months to get the new AVN head unit. During that time I contacted Hyundai Customer Support for help. After requesting for a lemon-law refund, the AVN head unit "magically" appeared at the dealer and was installed in about a day. I'm happy that the dealer was able to diagnose the problem correctly, but disappointed that I had to threaten legal action.

    New BM2 profile attached below. IMG_2273.jpeg
    electriceddy likes this.
  5. MSimpsonNJ

    MSimpsonNJ Active Member

    Hi all - following this thread and hoping to get some insight from you on this issue. 2022 Ioniq 5 SEL RWD. No problems with the 12 volt until about 6 months ago when I went to the car and it was dead. Was keeping the car charged to 20% or higher based on reports that this could help avoid the 12 volt problem while Hyundai figured out a permanent fix. Was able to jump it and made appointment with the dealer. This was around the time of the ICCU recall so they did that (ICCU checked out fine) and they told me to keep it at 35% while Hyundai continued to look for a fix. Seemed to help though after a bit I noticed that I never was seeing the amber light on anymore (which I realize could just be because of timing). Anyway, about two weeks ago the 12v failed 3 or 4 times over a 2 day period and my dealer got me in to complete the 9A1 recall (apparently there was an update August 14th). When I got the car home I noticed when I went out to the car later the amber light was on, which made me happy since I had not seen it for months. Then I noticed that it was on EVERY time I went to the car. So it appears that it is now constantly topping off the 12v. I just measured the voltage across the terminals and it's at 12.25 (with the amber light on). Does this sound like the 12v is in need of replacement? I think 12.25 is low for a "resting voltage" and the car should be charging it up to about 12.7 or higher, correct?

    I just ordered a battery monitor which I will install to gather some data points but I figured I would ask the experts (you guys) in the meantime.

    Thanks in advance.
  6. Zuinige Rijder

    Zuinige Rijder New Member

    @MSimpsonNJ When the car is charging, it will charge with 14.8 Volt. Normally my car will not go beneath around 12.5 Volt, before it starts charging the 12 volt battery. Examples of battery monitor of my car in this video:

  7. To remove this ad click here.

  8. MSimpsonNJ

    MSimpsonNJ Active Member

    Interesting and thanks. I just noticed also that the SOC of the 12v is only at 68%. Wonder if I have a bad battery...
  9. MSimpsonNJ

    MSimpsonNJ Active Member

    And following up - I charged the main battery overnight with my level 2, and the SOC of the 12v only went up to 71%

    Sent from my iPhone using Inside EVs
  10. It is possible that your battery may have been "damaged" by several past incidents of being dead. It may still charge up, but won't hold capacity as when it was new. However, when the dealer does their battery check it may still show OK. Take it to a battery shop and let them test it (for free). They usually have better equipment than a dealer. If they find it defective I would push for a battery replacement.

    I actually went through that scenario with my Solterra. It sat in port for a long time due to that wheel recall and by the time I got it was 8 months after manufacture. It ran dead on me a couple times. I charged it up at home, and it would reach "full" pretty quickly. But after having ACC on for a very short time (a few minutes) would go dead again. I took it to the dealer and to my surprise it tested OK. I then had it tested at a local battery shop (Edmunds) and they said it was defective and not able to hold a charge for long, which is exactly what I was experiencing. I went back to the dealer and pushed for a replacement, telling them about the battery shop test. They then relented and agreed to replace it. It has been good ever since with the new battery.
    electriceddy likes this.
  11. Sandroad

    Sandroad Well-Known Member

    Just to help out a the amber light referred to the one on the center of the dash and does it represent charging of the 12V battery?
  12. To remove this ad click here.

  13. Yes.
    Sandroad likes this.

Share This Page