Dead Kona EV!

Discussion in 'Hyundai Kona Electric' started by Wildeyed, Sep 28, 2019.

  1. victor_2019

    victor_2019 Active Member

    the car has a 12V lead acid battery and a ~380 (??) volt lithium battery.

    when the car is on, the high voltage battery is connected and a DC/DC converter provides 12V to the auxiliary systems and charges the lead acid battery.

    when the car is off, the high voltage battery is disconnected. only the 12V lead acid battery is there to run your auxiliary ssytems, which includes all the computers/electronics of the car.

    if the 12V battery is dead, the car is dead, even if you have a full charge in the lithium ion high voltage battery.

    the 12V battery is constantly monitored and periodically topped up from the high voltage battery to prevent a dead battery/car.

    If the 12V battery is bad, this top-up wont help. I also don't know how often the 12V battery is checked, maybe if you have a high enough drain on it it might become fully emptied before the car checks it for topping up.

    or perhaps your circuit that charges the 12V battery is defective.
    ehatch likes this.
  2. eastpole

    eastpole Member

    My Kona was dead at the dealership with a drained 12V battery when I went to pick it up and drive it for the first time! Not a good experience either. (But at least it wasn't raining!)

    My understanding is that this problem can be even worse on a Tesla model S, where there is no mechanical release for the hood (true?) so you have to charge the 12V battery blindly through an access port. Of course you also can't open the car; no door handles.

    In any case, I share your overall displeasure with the situation. The car should ship with the 12V battery-saver enabled and said feature should actually work every time. :| I suspect getting this right is harder than it looks, but I don't yet know how or why.
    ehatch likes this.
  3. Wildeyed

    Wildeyed Well-Known Member

    I hope this isn't the start of a saga like the "clunk" or "hiss" epics but the dealer just called after 5 hours working on the car. Apparently there are error codes galore and they have been working directly with Hyundai (always a frightening sign) to try to figure out what's wrong. They need to order parts, a hybrid drive unitsomethingorother. They don't know if it's in stock yet or how long it will take. So it's not (just) the battery, it's something bigger. Apparently the car has been starting fine on and off all day. Pray for me.
    Domenick, CJC and ehatch like this.
  4. A while ago I did some logging of the 12V battery out of curiosity. When off, it charges for 20 minutes every 24 hours (strictly 24 hours off followed by 20 mins charge followed by 24hrs off etc.), too close to a round figure to be coincidence or triggered solely by the battery voltage . It seems to be random whether or not you see the "battery was charged" message on startup. When the car is turned off, draw from 12V is quite high for a few minutes, eventually settling down to a very low level - under 10 milliamps.
    I suspect that there is some rare combination of circumstances that prevent it going to sleep fully.
    I don't recall the figures offhand but certainly several amps, enough to discharge the battery overnight.
  5. KiwiME

    KiwiME Active Member

    I have to wonder if the intent was that it's not needed for cars in daily service, hence the setting, although what harm could it do to leave it on?
  6. electriceddy

    electriceddy Well-Known Member

    None of these error codes showed up on your dash? Can you still drive it? I thought the jump solved your issue.
  7. Wildeyed

    Wildeyed Well-Known Member

    The car woke up and drove fine for as long as it took to get it on the flatbed tow. I wasn't about to ignore what happened and keep driving it even when it seemed cured. I don't want to live with that sort of uncertainty. And it turns out that there appears to be some sort of underlying cause, given the fault codes - so it was the right move. I want to know what happened and that it won't happen again.

    It was a bit hectic but to my recollection there were no warning lights on the dash once the car was jumped. When it died the car with the key silhouette inside it (security alert) was displayed briefly and the horn alarm beeped during the jump. I think the car thought it was being hijacked.
    ehatch likes this.
  8. ehatch

    ehatch Active Member

    This seems more intense than sentry mode that drains the 12V,and drive Li battery where you could end up with a dead Model 3 depending on your SOC when you parked it. Hyundai should send a firmware out that will correct the BMS voltage demand when the Kona's off? Wonder which of us will be the first to have a dead Kona while traveling for a week ,or more,unplugged.
  9. ehatch

    ehatch Active Member

    Can you please share the fault codes from your DTC scan? As part of our service,some of us with the hiss/squeak/clunk,and possibly higher than "normal" sleep mode drain on the 12V, Li may want to know.
  10. Wildeyed

    Wildeyed Well-Known Member

    I'm afraid I will not know the specific codes as it's the garage that performs that work. I'm not one of you guys who seem to carry amp meters and code readers with you every time you leave the house! :)
    BC-Doc likes this.
  11. Wildeyed

    Wildeyed Well-Known Member

    As documented above my car is in the shop waiting for parts. I just got my monthly health report from Bluelink. It reports all systems normal as does the live Bluelink diagnostics test. Maybe take yours with a grain of salt!
    ehatch likes this.
  12. ericy

    ericy Active Member

    Do we have any idea what size/model of 12V battery they went with here?

    A standard battery from an ICE is really unsuitable as it isn't designed for this purpose.
    ehatch likes this.
  13. KiwiME

    KiwiME Active Member

    From the type number it's the same as used in some of Hyundai/Kia gasoline cars. CMF45L-DIN - 45Ah - RC 80 Min - CCA 410A
  14. Jamas

    Jamas Active Member

    Yea, in some regards, BlueLink is pretty useless.
  15. ericy

    ericy Active Member

    Figures. The only advantage to this that I can see is that you would be able to use standard jumper cables on the thing. Either to give someone else a jump, or receive a jump if the 12V battery is dead.
  16. Devhead

    Devhead New Member

    This dead aux battery anomaly just happened to me. I drive the car regularly, more than an hour yesterday. I remember turning the car off and had I not, the car would have beeped quite loudly at me.

    Today I go out to the car and it is dead. So dead that when I plugged it in to charge the traction battery it would not charge. The traction battery had a 51% charge. I got out a volt meter and discovered the aux battery had an 8 volt charge. The car is less than 6 months old.

    I disconnected the aux battery from the car and put it on a 12v 10amp charge for 45 minutes. Reconnected it to the car and it came back to life.

    Has anyone been able to get the dealer to replace the aux battery after having this problem?
    ehatch likes this.
  17. electriceddy

    electriceddy Well-Known Member

    I would monitor the resting voltage hopefully more than 12.6 V (eliminate parasitic drain). Check that the OB converter is charging at 14.4 V when in run mode. Do you make a lot of short trips?
    A load test should indicate a defective aux battery if the voltage drops.
  18. Devhead

    Devhead New Member

    Thanks E-daddy. I'm letting it rest for an hour and then will be checking it again. The battery was at 12.6 when I turned everything off. I could hear bubbles inside the aux battery but they were tapering off, they were much louder when the traction battery was on the charger.

    Either way, I'm calling the dealer tomorrow. I have a 1300 mile road trip coming up next week and I don't want this to be a worry.
    ehatch and Wildeyed like this.
  19. electriceddy

    electriceddy Well-Known Member

    In light of what happened to Wildeyed with error codes, a trip to the dealer couldn't hurt ;)
    ehatch likes this.
  20. Wildeyed

    Wildeyed Well-Known Member

    So, a question for you: did you immediately jump to the conclusion it was the 12 volt battery? If so, why? It was literally the last thing that I thought of. I just never would have fathomed that I would have a dead battery on an electric car. Now, had it been an ICE car it would have been the first thing I thought of.

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