My 2022 Kia Niro Premium had another dead 12V battery today. The voltage across the terminals was only about 4 volts. I had the battery tested and it’s in good condition. I’ve stopped using Android Auto to see if that was the cause, so that’s not it. All the doors were shut, and the interior lights were off. I managed to start it with my Noko jump pack, and now the 12V battery is on charge again. I’ve booked it for diagnostics at Kia, but I’m not expecting them to find anything since it seems pretty random. I’ll report back with what I find, though, in a few weeks (the earliest they could give me a loan car).
If you’re getting frustrated and they don’t find anything, here’s a simple way to figure out what’s draining the battery when the car is off: https://youtu.be/xBVmbYBxMyo
You can use a multimeter on the battery to check the amp draw. Let the car sleep, and then pull out fuses one by one until the current draw drops to zero. That should help you find the issue. But of course, if it’s an intermittent problem, it will be tough to troubleshoot.
@Cedar
Great suggestion – hopefully, the Kia techs will do something similar, but I’m not getting my hopes up too much.
Jordan said:
@Cedar
Great suggestion – hopefully, the Kia techs will do something similar, but I’m not getting my hopes up too much.
Opening the door will probably wake the car up. It’s best to have the 12V battery tested somewhere just to make sure.
@Niall
The battery’s been tested, and it’s around 90%.
Jordan said:
@Niall
The battery’s been tested, and it’s around 90%.
Even with 4V? That’s surprising to hear.
Jordan said:
@Niall
The battery’s been tested, and it’s around 90%.
Even with 4V? That’s surprising to hear.
The car started, and my wife took it out today, so I’m hoping it’s fine. This has happened before and it’s been alright each time.
@Jordan
Of course, the battery in my multimeter died, so I couldn’t check the charge myself.
Jordan said:
@Jordan
Of course, the battery in my multimeter died, so I couldn’t check the charge myself.
I’ve read about issues with the ICCU and some recalls on forums like the ones for the EV6 and Ioniq 5. Manufacturers could definitely do better in these areas.
Jordan said:
@Niall
The battery’s been tested, and it’s around 90%.
A lead-acid battery that drops to 4V is pretty much dead. It won’t hold a charge for long after that.
Jordan said:
@Niall
The battery’s been tested, and it’s around 90%.
A lead-acid battery that drops to 4V is pretty much dead. It won’t hold a charge for long after that.
I’ll go tell the battery that, haha. I’ve been testing it daily and right now it’s at 12.8V. It’s dropped to 4.x volts a couple of times. The last two times I had it tested by battery shops, they told me there’s nothing wrong with it and it’s not worth replacing. I’m sure something in the car is draining it randomly, and I want Kia to fix it under warranty.
@Jordan
Check out Ok_Job_7427’s post. He had the same problem, and replacing the battery fixed it. I have a 2022 model as well, and haven’t had any issues, but I’m thinking of replacing mine since it’s near the end of its life.
4V? Is the vehicle charging the 12V properly? Short trips under 20 minutes might not give the vehicle enough time to charge it. There are also some other common causes of a dead 12V battery: ICCU failure and ? Excuses! | Hyundai IONIQ Forum
Several conditions can cause the ICCU to fail in charging the 12V, and some of these aren’t even related to a failure of the ICCU itself. Here’s a quick list of things to consider:
- Dash cameras with a voltage cutoff for stationary runs can affect the 12V battery’s health, leading to faster degradation if they’re used too often.
- Any aftermarket device drawing power from the 12V while the car is off won’t be considered by the ICCU’s charging logic.
- Leaving an OBD2 dongle plugged in while the car is off can put extra strain on the battery and cause unnecessary traffic on the OBD2 CAN bus network.
- Do not use Lithium Iron Phosphate (LFP) batteries or other chemistries with their own Battery Management Systems (BMS), as they’re not supported on the E-GMP platform.
Please keep these tips in mind to avoid any issues with your car’s electrical systems.
@Niall
The flashing red light comes on when I plug the car in, which indicates it’s charging the 12V. I live in a rural area, so every trip is at least an hour. The car was used two days ago and was fine, but today it was dead with about 4V.
@Jordan
Do you have a multimeter to check what the actual voltage being sent to the 12V is? It should be around 13-14V. 4V seems too low. If that’s the case, I’d expect the 12V to be damaged. I had a 12V battery on a smart charger for several days, and once I disconnected it, the voltage dropped below 10V. You might want to look at this link for more info on hybrid and electric inverters trying to charge the 12V: https://www.batteriesplus.com/blog/power/car-battery-care
@Niall
Yes, it’s on a charger now, but I’ll check tomorrow.
Jordan said:
@Niall
Yes, it’s on a charger now, but I’ll check tomorrow.
I hope you’re using a 12V smart charger. I use a Ctek 3300 for my 12V. But I also suspect the 12V may be damaged. It must be a PHEV, right?