NavinRJohnson
Posts: 42
Joined: Tue Nov 04, 2014 8:43 am

12v battery keeps draining daily - what are the biggest culprits?

Tue Apr 20, 2021 8:18 am

Wondering what the biggest culprits of this common issue are and how to properly diagnose. I suspect my Ford service center will not be willing to diagnose the issue unless they actually see/experience it happening. Is there a highly common culprit? Do I need to do the painstaking multimeter trick and narrow down exactly which circuit has the draw? Should I just hand it to Ford and hope they experience the issue while it's in their hands? I think I have some extended warranty left. It's a 2014.

Heima
Posts: 151
Joined: Thu Feb 21, 2019 11:46 pm

Re: 12v battery keeps draining daily - what are the biggest culprits?

Tue Apr 20, 2021 5:54 pm

First off, how is the battery recharging daily, and how do you know it is draining?
Is that the original battery? If so, you probably should replace it.
If the battery is fairly new, try removing fuse F1 (I believe) the fuse for the TCU.
If that stops the daily drain, then there is a firmware update that might help.
If the drain continues, you're going to need a good multimeter to do the checking.
Surrendering your vehicle to the ineptitude of the dealer is a money pit for you.

triangles
Posts: 1145
Joined: Tue Aug 16, 2011 11:40 am
Location: Toledo, Ohio

Re: 12v battery keeps draining daily - what are the biggest culprits?

Wed Apr 21, 2021 5:33 pm

assuming your battery isn't junk... viewtopic.php?f=14&t=3812
2014 Blue Candy FFE
http://www.fuelly.com/car/ford/focus/2014/triangles/303811 (since this forum doesn't allow BBcode in sigs)

NavinRJohnson
Posts: 42
Joined: Tue Nov 04, 2014 8:43 am

Re: 12v battery keeps draining daily - what are the biggest culprits?

Thu Apr 22, 2021 1:08 pm

triangles wrote:
Wed Apr 21, 2021 5:33 pm
assuming your battery isn't junk... viewtopic.php?f=14&t=3812
It's not. And thank you for documenting what you experienced - what a nightmare scenario. Thankfully looks like you found a workaround and documented the whole thing for us. How can I tell I've got the same thing draining my 12v? I do have a multimeter.

I've had this issue for a year and just dealt with it. Very frustrating! So the Galley Power unit is still working for you along with circuit/fuse thing?

triangles
Posts: 1145
Joined: Tue Aug 16, 2011 11:40 am
Location: Toledo, Ohio

Re: 12v battery keeps draining daily - what are the biggest culprits?

Tue Apr 27, 2021 6:20 pm

Well the easiest thing to do would be to pull the F1 fuse which supplies power to the TCU. If the problem goes away then you know it's your TCU.
Image

Ford's procedure is to do a draw down test as I described in my linked thread above. This checks battery drain and finds the culprit.

I only use the LVD in winter when I want to use go times as running the battery down to 12.1V is hard on a lead acid battery. It is like 40% SOC. Otherwise like now I just pull the fuse and not care about the lack of TCU.

I realized my 12V battery was nearing it's end of life when I tried to jumpstart my motorcycle and it didn't have enough to power to turn over the motorcycle engine. The motorcycle battery is only 160 CCA. I replaced my 12V with a LiFePO4 battery. probably a bad idea because LiFePO4 chemistry pretty much stops below freezing. Then I realized I don't need current, just enough juice to energize the contactors. Than and I put a LiFePO4 starter battery in another motorcycle I rode often in winter, 8 years ago and it is still works just fine.
2014 Blue Candy FFE
http://www.fuelly.com/car/ford/focus/2014/triangles/303811 (since this forum doesn't allow BBcode in sigs)

Return to “Technical Discussions”