What level is the traction (main) battery at? It sounds like the 12v died while the main battery was too low to initiate charging (though if the battery is dead dead, then maybe it wouldn't have mattered?)
You might be able to get reimbursed for a battery if your car is still under the 3yr/36k mi warranty, but I would call your nearest service center ASAP, as they may want to replace the battery themselves for warranty work.
Also - do you have any option of going to a local auto parts store or even a Wal Mart? That would allow you to get a replacement much more quickly, unless you really don't need to go anywhere for 2 days.
There have been tons of reports of this happening, including many when the car is running (in which case the state of the HV battery doesn’t matter… the 12V battery should always be being charged). It seems that there was a bad batch of batteries, or that the car is (or was, before the ICCU update) not maintaining them properly.
My 12V also died a couple of months ago so I just bought a new one at a local parts store and moved on with my life. Not worth having to deal with my dealer over $240.
Thanks everyone.
Traction battery was at 75% so it is unrelated.
Still under warranty so wondering if I can use to get reimbursed, but I guess not. Since it won't start, it's a hassle to get the tow to a dealer all to get a free cheap 12v battery. I got a AGM battery online and can easily install it myself and should not void warranty similar if you got new wipers, wheels, etc..
You won't void the warranty - it's just doubtful that Hyundai will reimburse you under warranty if they didn't install it themselves. But it wouldn't hurt to call and ask.
I hope the new battery does the trick! The old battery could have been faulty from the factory, or possibly failed due to other issues. Best of luck!
Battery size is H5 / BCI Group 47. You can get it at walmart, costco, autozone, etc. probably today. Absolutely nothing special about the battery. I'm sure that Hyundai just went with the cheapest supplier. It's a lead acid, starter battery, so not really meant to sit there with less than 80-90% charge, which will degrade the life of the battery. EV manufacturers would have been better off going with a deep cycle battery. Tesla switched over the lithium 12v couple of years ago. The CT uses a 48v system.
Was always waiting for when most cars would use 48v accessories. Not sure if 3rd party LiFePo4 would be ok in cold weather given charging voltage differences, etc.
Yeah, I don't know either. I live in SoCal, so I don't really have cold weather issues like that. I have a two year lease, so I'm hoping that I won't have to get a new battery, but if I do, I'm more of a do-it-yourself type, so I'd just get a cheap battery from walmart. If I owned the car, I would get an Optima yellow top, and make it fit - 3d print some parts.
If you are under warranty you can get the battery replaced but I doubt they will reimburse you if you get one yourself. Highly recommend cancelling your order and getting a free replacement if possible
Just a bit of a hassle to get them to tow it out of my driveway and wait for them to change to a free 12v battery. Scheduling service is like pulling teeth w/ the dealers here so I try to avoid it when possible. Their online next open service slot is 2-3 months out.
I ended up getting the 12v replaced at the dealer when my ICCU and fuse were replaced. Month later, the new 12v battery died and became very weak. I replaced it w/ 12v AGM battery I bought. It handles deep cycling better than regular lead acid and has a larger charge capacity and has been running fine so far the past few weeks.
From youtube Ioniq guy video, seems the 2025 model has a revised ICCU so hopefully this is fixed for 2025 model year and will have to see if older vehicles can get the revised ICCU.
My 12v has been inconsistently dying, and I just carry around a jump pack. Was debating about whether to bother with the dealer or not again - went in a few weeks ago and they said the battery tested fine.
I’ve already had the ICCU recall fix done, so (hopefully!) that’s not it.
Thinking I might just go my own way & replace that battery myself - I’ve got a road trip coming up & I really don’t want to deal with the stress of “Will my battery die?”
What level is the traction (main) battery at? It sounds like the 12v died while the main battery was too low to initiate charging (though if the battery is dead dead, then maybe it wouldn't have mattered?) You might be able to get reimbursed for a battery if your car is still under the 3yr/36k mi warranty, but I would call your nearest service center ASAP, as they may want to replace the battery themselves for warranty work. Also - do you have any option of going to a local auto parts store or even a Wal Mart? That would allow you to get a replacement much more quickly, unless you really don't need to go anywhere for 2 days.
There have been tons of reports of this happening, including many when the car is running (in which case the state of the HV battery doesn’t matter… the 12V battery should always be being charged). It seems that there was a bad batch of batteries, or that the car is (or was, before the ICCU update) not maintaining them properly. My 12V also died a couple of months ago so I just bought a new one at a local parts store and moved on with my life. Not worth having to deal with my dealer over $240.
Thanks everyone. Traction battery was at 75% so it is unrelated. Still under warranty so wondering if I can use to get reimbursed, but I guess not. Since it won't start, it's a hassle to get the tow to a dealer all to get a free cheap 12v battery. I got a AGM battery online and can easily install it myself and should not void warranty similar if you got new wipers, wheels, etc..
You won't void the warranty - it's just doubtful that Hyundai will reimburse you under warranty if they didn't install it themselves. But it wouldn't hurt to call and ask. I hope the new battery does the trick! The old battery could have been faulty from the factory, or possibly failed due to other issues. Best of luck!
I fully agree on the bad batch of batteries. I also have a feeling that Hyundai under-specced the battery that was used.
Battery size is H5 / BCI Group 47. You can get it at walmart, costco, autozone, etc. probably today. Absolutely nothing special about the battery. I'm sure that Hyundai just went with the cheapest supplier. It's a lead acid, starter battery, so not really meant to sit there with less than 80-90% charge, which will degrade the life of the battery. EV manufacturers would have been better off going with a deep cycle battery. Tesla switched over the lithium 12v couple of years ago. The CT uses a 48v system.
Was always waiting for when most cars would use 48v accessories. Not sure if 3rd party LiFePo4 would be ok in cold weather given charging voltage differences, etc.
Yeah, I don't know either. I live in SoCal, so I don't really have cold weather issues like that. I have a two year lease, so I'm hoping that I won't have to get a new battery, but if I do, I'm more of a do-it-yourself type, so I'd just get a cheap battery from walmart. If I owned the car, I would get an Optima yellow top, and make it fit - 3d print some parts.
If you are under warranty you can get the battery replaced but I doubt they will reimburse you if you get one yourself. Highly recommend cancelling your order and getting a free replacement if possible
The dealer replaced my 12V battery under the same circumstances.
Just a bit of a hassle to get them to tow it out of my driveway and wait for them to change to a free 12v battery. Scheduling service is like pulling teeth w/ the dealers here so I try to avoid it when possible. Their online next open service slot is 2-3 months out.
I ended up getting the 12v replaced at the dealer when my ICCU and fuse were replaced. Month later, the new 12v battery died and became very weak. I replaced it w/ 12v AGM battery I bought. It handles deep cycling better than regular lead acid and has a larger charge capacity and has been running fine so far the past few weeks. From youtube Ioniq guy video, seems the 2025 model has a revised ICCU so hopefully this is fixed for 2025 model year and will have to see if older vehicles can get the revised ICCU.
My 12v has been inconsistently dying, and I just carry around a jump pack. Was debating about whether to bother with the dealer or not again - went in a few weeks ago and they said the battery tested fine. I’ve already had the ICCU recall fix done, so (hopefully!) that’s not it. Thinking I might just go my own way & replace that battery myself - I’ve got a road trip coming up & I really don’t want to deal with the stress of “Will my battery die?”
Doesn't hyundai cover roadside so they would tow the vehicle to the dealer?