Prime 12V battery dies after 10 mins running accessories in cold

I'm not an expert on the Prime, but I don't see how the 12V will go flat with the car in READY. Perhaps there is a timeout that will turn the car OFF after prolonged inactivity.

 

Perhaps an issue with the DC to DC converter or associated ECU which is what charges the 12v battery. As far as the hood not opening I thought that was a mechanical thing and not dependent on any electric power. I never looked but I assumed a mechanical cable ran from the unlock switch handle to the hood lock. Perhaps the cable has moisture in it and needs some lubrication or other servicing?

 

Assume you’re parking outside? Is there a garage you could declutter, get the car into shelter? Or if you’re in a driveway, would one of those tarp carports be feasible? At the least, cardboard cover on the windshield might help. And do as much windshield clearing before starting the car.

Be careful with warm water poured on the car, may stress the paint. Maybe a hair drier, if a cord will reach.

 

If you are in READY in the EV mode it should not drain the 12v battery. But if you did this in ACC mode (without pressing the brake) then 10 min is long enough to drain the 12v battery.

Yeah, as others said, if this is happening in the READY mode, then there must be something not working correctly.

I never had to open the hood when it is ice covered, but that problem would not be PP specific. Can happen to any car. Just a few days ago, I couldn't open the charge port of my Escape PHEV when it was covered by ice.

 

2nd what @Salamander_King said. Maybe you hit the start button without hitting the brake or a fraction of a second after hitting the start button. I've done this before, but the battery isn't very big so it'll drain quite rapidly. You may have developed a soft short in one of the cells too like I did. They can only determine this if the battery is already dead. If you drive to the dealer, it'll charge the battery enough to pass their tests. What I did is leave the lights in auto mode and when you get to the dealer let lights turn off by themselves, usually after 30 seconds. From what you describe you may also have a shorted cell. Whatever it is still under warrantee.

 

Repeatedly fully discharging the lead acid battery then recharging it will shorten the battery life.

Spray some silicone spray on the rubber parts on the hood-to-body area to keep them from freezing together. If you have a sheet of ice on the hood, that's a problem.

 

I have a 2022 Prime and I am in extreme cold winters. Never had your issues.

As a 2021, you are still under warranty. Take it in to the dealer for resolution.


iPhone ?

 

Should probably adjust your morning routine to turning-on the front windscreen defroster. This should automatically start your ICE.

1. if the ICE doesn't start, you know your not in ready mode and that your draining your battery.
2. it's going to burn some gas, but your cabin will be nice and toasty, when your ready to leave.

Hope this helps.

 

Phone battery must have died too

 

As some others said, you left the car in the ACC mode, not in the READY mode. The 12-V battery will drain unless the car is in the READY mode.

The 12-V battery will charge both in the EV mode and HV mode as long as the car is in the READY mode. In fact, it probably charges slightly better in the EV mode.

 

Note that there are three ignition positions:

• Accessory mode
• Ignition ON
• READY

The first two are displayed in the left of the MFD screen, and the READY indicator is toward the right. If you don't press the brake fully, the car typically goes to the Ignition-ON mode.

The 12-V battery only charges in the READY mode, and it does so both in the EV and HV modes. My best guess is that the car was left in the Ignition-ON mode.