zblitz1

My 2011 CT has been having a slow battery drain issue for a while now - if the car sits for more than two days when it's cold outside the battery will die and I have to jump it. I replaced the 12v battery in 2020 but the issue still exists. Recently the car has been dying after only a few hours but the other day it magically came back. I got in the car, no lights, nothing, no ready button, no dash lights, absolutely dead, fully disconnected from any electrical source dead. Two hours later I came back to try to jump the car and it was on - accessory power, dash lights on, ready button glowing, and it started right up. Yesterday I had the same issue where I drove the car to work in the morning, and by the afternoon it was dead again.

Has anyone had a similar issue or know what might be a potential source of this issue?

Thanks!

TobiasSing

Hmm, that sounds like the battery connections are loose.

morganc

Might want to check the master combination fuse for issues. The only way to solve this is to poke around with a multimeter to see the last point at which you have voltage running into the car. Could be something way upstream that manifests as bad batt connections or main fuse.

zblitz1

Which panel should I start with - the interior panel or the one in the engine bay?
Is it something to check while the car is running or is it something to poke around and see if there's something draining the battery while it's off?

It seems like when I hit the power button to turn the car off it shuts everything off as if I've hit a master battery disconnect. The radio and climate control resets, interestingly the clock remembered the time most recently.

morganc

Engine bay is where the main combination fuse is. Good place to start.

When you replaced the battery in 2020, did the issue go away for a while, or has it been prevalent over the last two years?

If it only recently came back; replace the battery again. (ok, have it tested, first). A common failure mode on batteries is a bad connection between plates, so under low power draw, the battery looks full, but as soon as you demand power from it, it appears "dead."

It's more obvious on non-hybrid cars, due to the fact that the starter is using the battery..but could be less obvious on our cars.

Check all of your engine bay grounding straps (and wiggle them, too). With enough poking and prodding, a meter should be able to point you in the right direction.

Salmo119

Ever found A fix ?

Same issue on my 2017 fsport, Started last Friday .. Has done it on & off like 3 times .