How to Recondition/Service Your 12V Battery

[Mach-Lee]

Updated the OP with information about HVJB/BECM replacement as a potential fix for reoccurring 12V drain issues as reported by several forum members.

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[RickMachE]

Drove my car today after it sat since Friday plugged in. Big message on screen that system was shut off to conserve battery AFTER I started it. Hope it is an update glitch.

 

[GrumblesTheDog]

Watching this exceptionally informative thread with great interest now -- I've gotten the 12V fault, service soon message twice.

The first time, it came shortly after I'd installed a dashcam but WITH a discrete battery pack (which is in turn connected to an ACC circuit) specifically out of concern I'd toast the LVB with a constant low-level draw. I did also have the doors open for like 30-45 minutes at a time to get the trim off etc. Maybe coincidental?

The second time just happened randomly this morning, which is worrying me a bit, although lately I haven't been plugging in every night and have had several scheduled departure times occur off-plug. Could that cause this?

I only have a NOCO Genius, so it sounds like I may need to find a brawnier device to try this. If I understand these posts correctly, I can accomplish the same effect with a power supply set to ~13.7V and just watch for current to drop into milliamp range?

 

[Mach-Lee]

The first time, it came shortly after I'd installed a dashcam but WITH a discrete battery pack (which is in turn connected to an ACC circuit) specifically out of concern I'd toast the LVB with a constant low-level draw. I did also have the doors open for like 30-45 minutes at a time to get the trim off etc. Maybe coincidental?

The second time just happened randomly this morning, which is worrying me a bit, although lately I haven't been plugging in every night and have had several scheduled departure times occur off-plug. Could that cause this?

I only have a NOCO Genius, so it sounds like I may need to find a brawnier device to try this. If I understand these posts correctly, I can accomplish the same effect with a power supply set to ~13.7V and just watch for current to drop into milliamp range?

Yes leaving doors open is known to cause the error message. The second message was probably still a result of it being low. Hopefully it will be charged back up next time the vehicle is scheduled to be charged and it won't be a further issue.

And yes power supply at 13.7V for a day or two down to <50 mA is the best way if you wanted to charge it up manually.

 

[VegStang]

Dealer had my car to diagnose the front axel noise, will replace driver side, and for 3 days updated modules. Picked it up today and getting repeated 12 v fault service soon every time I start it up, then goes into deep sleep mode when turning off. I received one of these messages via the app while they had the car yesterday. Thanks for the write up.

I'm also getting an update message after starting the car saying at turnoff the car will finish the update, repeats on next startup.

 

[mkhuffman]

Dealer had my car to diagnose the front axel noise, will replace driver side, and for 3 days updated modules. Picked it up today and getting repeated 12 v fault service soon every time I start it up, then goes into deep sleep mode when turning off. I received one of these messages via the app while they had the car yesterday. Thanks for the write up.

I'm also getting an update message after starting the car saying at turnoff the car will finish the update, repeats on next startup.

Sounds like you need a trip back to the dealer...

 

[VegStang]

Yeah, I left the car plugged into the 110 all night and things have improved. I still may need to take it to the dealer, hopefully not until they get the axel part, but the update completed ("you may now remove your usb memory stick") and the car did not go into deep sleep when I got back from a 10 mi drive. The 12 v fault message came up when I started it today, but not the second time an hour later. ? that the message was part of the car functioning properly and it was able to recharge the 12v from the HV successfully- in spite of the dealer's efforts- but they did leave me grease/dirt on the light gray seats as an extra present to remember them for.

Sounds like you need a trip back to the dealer...

 

[Mach-Lee]

Yeah, I left the car plugged into the 110 all night and things have improved. I still may need to take it to the dealer, hopefully not until they get the axel part, but the update completed ("you may now remove your usb memory stick") and the car did not go into deep sleep when I got back from a 10 mi drive. The 12 v fault message came up when I started it today, but not the second time an hour later. ? that the message was part of the car functioning properly and it was able to recharge the 12v from the HV successfully- in spite of the dealer's efforts- but they did leave me grease/dirt on the light gray seats as an extra present to remember them for.

Sounds like the update wasn't installing properly because the battery voltage was too low. Hopefully the battery will be better now. I would recommend having 21P22 updates done if you haven't yet.

 

[VegStang]

That was my hypothesis, and it did turn out to be the case. 12v no longer giving off errors. I had the 21P22 updates done back in Jan, but the tech did not finish all the modules (seems to be fairly common) and still has not done so even though they had it for 3 days. The front axle part has come in so we will see if they do better next week. I do notice now that the lane keeping seems to be functioning differently (or not at all) now after the dealer installed updates- actually received a BC not available and no longer seeing the "bubble" around the car.

Sounds like the update wasn't installing properly because the battery voltage was too low. Hopefully the battery will be better now. I would recommend having 21P22 updates done if you haven't yet.

 

[mkhuffman]

I do notice now that the lane keeping seems to be functioning differently (or not at all) now after the dealer installed updates- actually received a BC not available and no longer seeing the "bubble" around the car.

In case you didn't see it posted in the forum, people who do their own FDRS updates ran into the same problem and it was eventually resolved with a module update. So if your dealer correctly applies all updates available for your VIN in FDRS, this problem should go away. You might need to report this to Ford CS if the dealer does not agree.

 

[VegStang]

Thanks for that, I had not noticed. I just spoke with support and they gave me the 21G01 program to have the dealer do, but as these last updates took them 3 days and they said there were still a couple modules left... I can only imagine next week at my service for the front CV boot the updates will extend it's shop time considerably.

In case you didn't see it posted in the forum, people who do their own FDRS updates ran into the same problem and it was eventually resolved with a module update. So if your dealer correctly applies all updates available for your VIN in FDRS, this problem should go away. You might need to report this to Ford CS if the dealer does not agree.

 

[P. T. Magoo]

What a great writeup!

Forgive me if this has been covered multiple times in 11 pages of replies, @Mach-Lee and others.

I'd like to just assume when my car finally arrives, that it'll need the 12 volt battery reconditioned, and I'd prefer to not spend a ton to do it. Maybe recondition it once a year or so thereafter.

Harbor Freight has this charger for like $40 without coupons. https://www.harborfreight.com/4-amp...ntrolled-battery-chargermaintainer-63350.html

There's a video here showing some of its features (after some annoying shots of snowmobiles starting up):

Looks to have an AGM mode, and it automatically switches to maintenance mode after it figures there's a full charge. It also has a way to hook a fused, quick-disconnect cable to the jump points so I could hook it up as desired with minimal fuss, leave the little cable tethered to the windshield washer fluid filler or some such for easy access.

Only thing that makes me wonder if it'd suffice is it tops out at 4 amps, and in your writeup you mention 10-20 amps as being preferred. I'm thinking 4 amps and longer run time? If I hook this thing up whenever the car is not in use for a week or so, disconnect it to drive, would that recondition the LVB properly, assuming it came to my garage somewhat sulfated?

Again sorry if this has been answered multiple times! My eyes glazed over after a few pages of this highly informative thread.

Thanks!

 

[generaltso]

I'd like to just assume when my car finally arrives, that it'll need the 12 volt battery reconditioned

I don‘t think you need to assume that. The vast majority of MMEs don’t have any issues with the 12V battery.

 

[louibluey]

What a great writeup!

Forgive me if this has been covered multiple times in 11 pages of replies, @Mach-Lee and others.

I'd like to just assume when my car finally arrives, that it'll need the 12 volt battery reconditioned, and I'd prefer to not spend a ton to do it. Maybe recondition it once a year or so thereafter.

Harbor Freight has this charger for like $40 without coupons. https://www.harborfreight.com/4-amp...ntrolled-battery-chargermaintainer-63350.html

There's a video here showing some of its features (after some annoying shots of snowmobiles starting up):

Looks to have an AGM mode, and it automatically switches to maintenance mode after it figures there's a full charge. It also has a way to hook a fused, quick-disconnect cable to the jump points so I could hook it up as desired with minimal fuss, leave the little cable tethered to the windshield washer fluid filler or some such for easy access.

Only thing that makes me wonder if it'd suffice is it tops out at 4 amps, and in your writeup you mention 10-20 amps as being preferred. I'm thinking 4 amps and longer run time? If I hook this thing up whenever the car is not in use for a week or so, disconnect it to drive, would that recondition the LVB properly, assuming it came to my garage somewhat sulfated?

Again sorry if this has been answered multiple times! My eyes glazed over after a few pages of this highly informative thread.

Thanks!

Several issues here. The vast majority of MME 12V batteries are good. Some 12V batteries (sometimes or regularly) are not properly charged by MME for any number of reasons other than the battery itself. Many of those batteries can be helped by some external charging at times (this case is unusual now, and improving generally with MME software updates).

As taught by @Mach-Lee it can always be desirable to condition your 12V battery. Once a year, once every couple of years, doesn't really matter, the idea is to occasionally follow his procedure, or to use a battery charger that does his conditioning procedure or equivalent, which can possibly/probably lead to a longer healthier 12V LVB life. @Mach-Lee's method does not require any particular current capability, and by the end, ideally draws a very small current from the charging source.

For the most part, the posts talking about using higher currents are discussing a charger or power supply for use during flash programming of the MME modules for those of us who take a license to the Ford maintenance software FDRS and do our own software updates (directly, not over the air). For this application, we use chargers, or ideally power supplies, that can supply between about 30A (suboptimal) to 100A (more than is needed, but a common programming power supply that a lot of us like).

The general (@generaltso) said it more succinctly. That was one of the reasons I was testing my 12V LVB so thoroughly when I was getting Ford 12V warnings. In each case, my 12V battery tested fine, no problems (three different batteries, two types). I had been getting repeated 12V LVB warnings which were bogus.

I guess there have been two most common problems related to the 12V LVB which are not the fault of the battery itself.

First, Ford continues to improve the software that decides when and how to charge the 12V LVB in all conditions (driving, accessory mode, parked, L2 charging of the high voltage battery, etc.). Some of the routine 12V LVB care and feeding by MME has been less than optimal, less so as time goes on with software improvements.

The other problems are more serious and require dealer service repairs. The most common problem which causes dead 12V LVB, is some kind of failure of a high voltage contactor/fuse box assembly which lives in the high voltage battery box under the car. High voltage battery junction box (hvbjb). In most of the cases, under some circumstances, the 12V LVB goes flat or dies, not because of a 12V battery problem; rather because depending on which contactors failed to operate, it is just not getting charged in one or more conditions (e.g. driving, while plugged into a L2 charger, etc.). No charging of the 12V LVB can solve this problem, which requires that the hv contactor/fuse box, the hvbjb be replaced.

 

[Mach-Lee]

What a great writeup!

Forgive me if this has been covered multiple times in 11 pages of replies, @Mach-Lee and others.

I'd like to just assume when my car finally arrives, that it'll need the 12 volt battery reconditioned, and I'd prefer to not spend a ton to do it. Maybe recondition it once a year or so thereafter.

Harbor Freight has this charger for like $40 without coupons. https://www.harborfreight.com/4-amp...ntrolled-battery-chargermaintainer-63350.html

There's a video here showing some of its features (after some annoying shots of snowmobiles starting up):

Looks to have an AGM mode, and it automatically switches to maintenance mode after it figures there's a full charge. It also has a way to hook a fused, quick-disconnect cable to the jump points so I could hook it up as desired with minimal fuss, leave the little cable tethered to the windshield washer fluid filler or some such for easy access.

Only thing that makes me wonder if it'd suffice is it tops out at 4 amps, and in your writeup you mention 10-20 amps as being preferred. I'm thinking 4 amps and longer run time? If I hook this thing up whenever the car is not in use for a week or so, disconnect it to drive, would that recondition the LVB properly, assuming it came to my garage somewhat sulfated?

Again sorry if this has been answered multiple times! My eyes glazed over after a few pages of this highly informative thread.

Thanks!

@louibluey covered things pretty well above. You do not need a high amperage charger to do the conditioning, it will just take longer if the battery is not at 90%+ charge first. The conditioning part takes less than an amp so almost any charger can do it provided it keeps the current flowing for an extended period (a lot of chargers shut off when full).

That HF charger has a voltage display, FYI you need to keep the battery in the 13.5-13.8V range for 24+ hours to do the conditioning. I see mixed reviews, seems like sometimes it doesn't go into maintenance mode or the voltage might not be set right. You can try it and see.

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