Battery life if the car sits for a year?

[NevadaTech]

Hello, I'm looking at a 2023 Kona Electric with 3000 miles on it. Yep, only 3000. My concern is the unknown state of health (SoH) for the battery. Was the car sitting at 0V for a year? I don't know. If it was sitting at 0, what is the concern? Is it that different than driving the car down 0? Is there an app that can measure SoH?

 

[electriceddy]

Hello, I'm looking at a 2023 Kona Electric with 3000 miles on it. Yep, only 3000. My concern is the unknown state of health (SoH) for the battery. Was the car sitting at 0V for a year? I don't know. If it was sitting at 0, what is the concern? Is it that different than driving the car down 0? Is there an app that can measure SoH?

If the HV pack has been sitting at a low SOC or deep discharge below the minimum voltage threshold, there very well could be some irreversible damage to one or more cells.
I use Car Scanner and an appropriate OBD reader (reference the Car Scanner website) and it works good.
Only problem... 2023 had 3P cell configuration, so it may not read the worst cell in that group. Only real way is to charge it to full and watch the cells balance, if one or more groups take longer to balance, odds are one or more are defective.

 

[NevadaTech]

I understand you are not Hyundai.
If a group of cells are bad, is that a warranty repair? Granted Hyundai may need X amount of bad cells before replacing the battery pack.

 

[JoeS]

@NevadaTech , insufficient information.
My first reaction was that I hoped the traction pack was originally sitting at around 50%SoC (in the hot Nevada sun?). What was its resting SoC? Was it really sitting outdoors in high summer temperatures for months on end?
Is the 12v battery dead? If so, the system would have driven the traction pack down because of the Kona's mindless daily waking up to recharge the 12v battery. This would have taken months; however, there is hope: as the main pack approached zero SoC (NOT zero volts), the hope is that the traction battery's bms would have kicked in and stopped the main pack's further discharge, leaving it sitting at a constant but protected low SoC. Contrary to popular belief, that is not harmful.
What is harmful is leaving the car's traction battery sitting fully charged, especially at high ambient temperatures.
As @electriceddy pointed out, need to test it.
Good luck!