My 12 V battery has now died twice- one week apart. I have an AGM battery , that was replaced at my cost while a dealership was "fixing" the AC charging, and killed the 12V in the process. They couldn't fix the original problem so I took it to a different dealership who did finally fix that problem 3 weeks later. Then I had a Check vehicle system warning light, which turned out to be a motor that controlled a cooling flap in the front of the car. Had that replaced. I then went out of town for 10 days, and left the car plugged in. When I returned it was dead. I had the 12V jumped, drove it to the dealer who said the battery was fine, and we presumed it was because I had been away. But exactly one week later, the car was dead again, needing a jump. Again I had the dealership look at it , and the battery status said I hadn't driven the car for a week, but I had actually driven it every day. And it stated the car was on for 19 hours the day I was away out of the country. I am realizing that both times the mirrors were open, and not in the closed state as they had been when I left the car. Last night, I came home in my husband's car, to find the mirrors in the open position, and I am sure I had left the car in the closed position. Any thoughts!?
Oh man, so sorry to hear that.
You shouldn't have a dead battery under any circumstances unless the battery itself is bad (it happens, even with new batteries), something is draining it or the battery management system isn't working normally. You should be able to leave it for as long as you'd like without the battery going flat providing the HV battery has a 20% or higher state of charge.
The fact that the dealer said "
...the battery status said I hadn't driven the car for a week..." but that you had actually driven it every day is very concerning.
@EV- Technician may have some more insight as to what that may mean.
You mentioned that the mirrors were opened when you thought you had locked it. Were the mirrors opened, but the car still locked? Are you in the habit of checking or using the KIA app regularly? (If you take a set of surround photos with the app, the mirrors will open but they should close right after.) Are you participating in any kind of a charging incentive program with your electricity provider? That info may help.
In the meantime, do you know if the KIA dealership performed an actual load test on the battery or were they just going by what the EV6's data showed? Did they run any diagnostics, including looking for parasitic or "ghost" drains on the system? Your work order(s) should show the details.
Otherwise it's possible that there is an unexpected draw on the 12v battery of some sort. Without having a battery monitor to see exactly what it looks like, it's difficult to say though.
One somewhat known issue is the car's two-way communications system being "pinged" too often. That can drain the battery to the point where the battery management system (BMS) can no longer keep up and stops trying after 10 failed attempts, judging that there is something wrong with the 12v battery itself or the 12v system.
One thing that can cause that is KIA Connect. For some reason it can go haywire for lack of a better term causing constant communication with KIA servers. Periodic communication is normal as it checks for it being locked, location, etc. But when it goes wrong it can "ping" the car every few minutes Owners have successfully resolved that issue a couple of ways. One is to simply change the KIA Connect account password. Others have had to delete their car from their KIA account (in the app or online) and then re-add it. All of the stats and info remain.
Others have had an issue with their utility provider after signing up for programs that allow the company to control when the vehicle is allowed to charge. Generally it allows them to restrict charging to low-demand times while offering owners discounts or rebates on their bills. In those cases folks have had to remove the vehicle from the program to stop the utility from constantly communicating with the car and running down their 12v battery.
The graph below is an example of the car's communications system being "pinged" far too often (the negative spikes), causing the battery to drain and eventually the BMS to quit trying to charge it.
You could try doing one (or both if applicable), to see if that helps.
Keeping the car locked and not checking the KIA app can help, especially if you're seeing unexpected activity like the mirrors opening, etc.
Otherwise, if the dealer is certain that there is no parasitic drain, the only way to really see if the "pinging" is an issue is to install an inexpensive battery monitor, one that can produce graphs like the one below so that you can see exactly what's happening with respect to when and how the 12v battery is being charged and discharged.
More here on that.
Hope that helps a little.
@EV- Technician and/or others should be along with additional thoughts.
