Should I just buy a better 12v battery at this point?

[GhostMav]

My truck has been sitting at the dealership for almost 3 weeks for no start issues related to the 12v battery. The first time I took it in they said battery was bad and replaced it and sent me away. 5 days later it wouldn't start again so had it towed to the dealership. Apparently they can't find any issue. No draws, no updates to be done, no fuse issues, no harness issues, and the battery is fine. So they want me to come pick it up. What? It literally won't start without being jumped?

I've seen people on this forum buy a better battery and put it in the truck and they say it fixed their problem. Should I just do that? I shouldn't have to spend $200+ on a battery for my brand new vehicle?

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[Gschaef]

There have been posts saying replacing the battery with a more powerful one has helped with these issues. The unanswered question is for how long? Many of the “bad” OEM batteries worked fine for 6-18 months before the problems showed up and it may be it took that long for them to degrade. And is that degradation caused by a bad battery, the BSM or both.

I don’t recall any posts saying they still had problems after installing a new battery but I’m guessing most of those replacements have not been in use that long so they may or may not end up having the same issues. Will the BSM eventually degrade those as well ? Nobody knows and Ford isn’t helping. It will take some more time for users to report their long term results.

Battery trickle chargers have seemed to help many owners but some have had issues even while using those. Others have said resetting the BSM helps and you need to reset the BSM after charging. What works for some doesn’t work for others. It’s a mess. At this point you might try contacting Ford Motors corporate service for help or is there another dealer in your area. Good luck.

 

[acapaldi]

TL;DR Fully charge your new battery and try a BMS reset before buying a replacement battery. They seem to help, but I don't know to what extent. Might be able to fix this without spending any money.

JohnKN had some luck with this battery BlueSpec has one of these installed in his hybrid, and I'm running this one in mine. None of them are what you would consider a cheap fix, but they all fit. And I don't know how it'll work out in the long run. I will say I feel much more optimistic than I did a week ago.

My key takeaway from everything that I've done to try to fix this issue on my own truck, is that the BMS system is very, very stupid. Or I'm just too stupid to understand how it works.

My previous battery would start fully charged each week, the battery management system (BMS) would be reset, and my battery would drain down into low voltage/ battery saver territory by the end of the week. I would lose more charge than I gained back by driving the truck every day. And the system would just kind of let it happen. I would typically see 0-2A going to the battery in FORScan, while my charge level continued to fall day after day. Sometimes I would get more charge amps going to the battery, but it would last maybe 15 minutes before going back to maintaining at 0-1A. It would just not charge the battery.

With the upgraded battery in mine, the truck has now established a "floor" of sorts. I dropped quickly to 68% charge, but it has now decided that whenever it dips below that, my charge amps spike up to 9A and the battery charges back up to that level. And my charge amps stay elevated until I get past that charge level. It doesn't just keep dropping until it dies anymore, or stop charging before getting back where it was. It's actively trying to charge the battery now when it's below a certain value.

My best guess at this point, is if the battery charge level drops quickly enough, it confuses the BMS. It's like it doesn't try to target the charge level listed in FORScan (80%), it somehow decides where it wants to maintain it at on its own. And if it drops fast enough, it can't find a place to settle and it just keeps dropping. Because it doesn't have a target it mind, it won't vary the charge amps to keep it at that target.

I would fully charge your dealer's replacement battery on a wall charger, reset your BMS and wait 8 hours without touching the truck. Then try to drive the truck multiple times per day for a week and see if it will stay charged after that. Keep the battery charged long enough to help BMS find a spot to maintain it at. Basically what I did, sans buying the expensive replacement battery.

With any luck, the BMS decides to maintain the battery at a level that isn't 0% or won't actively harm it over time. I didn't try this on a brand new Motorcraft, and my old one might have been dropping too quick for BMS to find its happy place. The AGM battery in mine could be the difference maker here, but I don't know for sure without a new to new comparison.

Another thing, your dealer might just have not reset the BMS after they replaced the battery, so the truck didn't try to charge it. Seems obvious, but eh. Might explain why the new battery went dead so quick. This all assumes that everything else about the truck is fine. I saw a post recently about a Ford engineer recommending a dealer swap a Body Control Module. No follow up yet, point being there could be more potential causes out there than cable/fuse/battery.

This could all just be B.S. I'm trying to draw conclusions about a system I did not have any involvement with and do not know how it works. I'm seeing results now, and trying to pick through what I've done to justify what I'm seeing. Whether my conclusions are correct... only Ford knows.

Before:

Current:

 

[RichardCranium]

Sounds like ford put some AI in the maverick, and this particular AI is a pissy little Bǐ+¢#. We all knew AI would ruin the world, and it’s name is BMS.

 

[skinnyboy]

TL;DR Fully charge your new battery and try a BMS reset before buying a replacement battery. They seem to help, but I don't know to what extent. Might be able to fix this without spending any money.

JohnKN had some luck with this battery BlueSpec has one of these installed in his hybrid, and I'm running this one in mine. None of them are what you would consider a cheap fix, but they all fit. And I don't know how it'll work out in the long run. I will say I feel much more optimistic than I did a week ago.

My key takeaway from everything that I've done to try to fix this issue on my own truck, is that the BMS system is very, very stupid. Or I'm just too stupid to understand how it works.

My previous battery would start fully charged each week, the battery management system (BMS) would be reset, and my battery would drain down into low voltage/ battery saver territory by the end of the week. I would lose more charge than I gained back by driving the truck every day. And the system would just kind of let it happen. I would typically see 0-2A going to the battery in FORScan, while my charge level continued to fall day after day. Sometimes I would get more charge amps going to the battery, but it would last maybe 15 minutes before going back to maintaining at 0-1A. It would just not charge the battery.

With the upgraded battery in mine, the truck has now established a "floor" of sorts. I dropped quickly to 68% charge, but it has now decided that whenever it dips below that, my charge amps spike up to 9A and the battery charges back up to that level. And my charge amps stay elevated until I get past that charge level. It doesn't just keep dropping until it dies anymore, or stop charging before getting back where it was. It's actively trying to charge the battery now when it's below a certain value.

My best guess at this point, is if the battery charge level drops quickly enough, it confuses the BMS. It's like it doesn't try to target the charge level listed in FORScan (80%), it somehow decides where it wants to maintain it at on its own. And if it drops fast enough, it can't find a place to settle and it just keeps dropping. Because it doesn't have a target it mind, it won't vary the charge amps to keep it at that target.

I would fully charge your dealer's replacement battery on a wall charger, reset your BMS and wait 8 hours without touching the truck. Then try to drive the truck multiple times per day for a week and see if it will stay charged after that. Keep the battery charged long enough to help BMS find a spot to maintain it at. Basically what I did, sans buying the expensive replacement battery.

With any luck, the BMS decides to maintain the battery at a level that isn't 0% or won't actively harm it over time. I didn't try this on a brand new Motorcraft, and my old one might have been dropping too quick for BMS to find its happy place. The AGM battery in mine could be the difference maker here, but I don't know for sure without a new to new comparison.

Another thing, your dealer might just have not reset the BMS after they replaced the battery, so the truck didn't try to charge it. Seems obvious, but eh. Might explain why the new battery went dead so quick. This all assumes that everything else about the truck is fine. I saw a post recently about a Ford engineer recommending a dealer swap a Body Control Module. No follow up yet, point being there could be more potential causes out there than cable/fuse/battery.

This could all just be B.S. I'm trying to draw conclusions about a system I did not have any involvement with and do not know how it works. I'm seeing results now, and trying to pick through what I've done to justify what I'm seeing. Whether my conclusions are correct... only Ford knows.

Before:

Current:

Awesome summary!

Recently had the battery draw down over time issue, then experienced a single instance of the battery going to 0% overnight. Two different situations, could be related, but not necessarily.

No DTCs, reset the BMS on the original battery after a full, disconnected, charge and has been fine for ten days. Seems to be settling at 12.5v after parking and the electronics have gone to sleep. That being said, I'm still disconnecting the battery when I park it at the airport this weekend, as I don't want it to sit dead for a week if the load(s) don't switch off.

Appointment at the dealership in the new year, really just so that there is a record of the complaint, and perhaps have some recourse, if there is ever a fix rolled out, and I'm outside of warranty. Don't expect the dealership to really diagnose an intermittent fault or re engineer the charging system, beyond their scope even if they could recoup the cost. The fix is squarely on Ford's shoulders, and hopefully they step up to help us and the dealers.

Feel for the owners that have this going on constantly, an exercise in frustration for sure.

Cheers.

 

[Montana]

Band-aid on an arterial wound, unfortunately. This has been going on for years now and on many more vehicles than just the Mavericks.

 

[Tim d]

My truck has been sitting at the dealership for almost 3 weeks for no start issues related to the 12v battery. The first time I took it in they said battery was bad and replaced it and sent me away. 5 days later it wouldn't start again so had it towed to the dealership. Apparently they can't find any issue. No draws, no updates to be done, no fuse issues, no harness issues, and the battery is fine. So they want me to come pick it up. What? It literally won't start without being jumped?

I've seen people on this forum buy a better battery and put it in the truck and they say it fixed their problem. Should I just do that? I shouldn't have to spend $200+ on a battery for my brand new vehicle?

Something doesn't make sense here,are you saying Ford put a new battery in under warranty,it's at the dealership, it won't start,and the dealership is saying nothing is wrong?

 

[jdtexas]

I am working with a cooperative Dealer and with Ford Customer Support, so far no one really knows what is causing the issue. I have now had mine back from Dealer for two weeks and it seems to be okay, but I continue to be skeptical that over the long term it has fixed itself. I am going to let it sit for 2 days and see what happens next. I do not feel anyone should have to install a new battery at their expense on a new 6 month old truck and I am not sure it is the battery, seems software related. The dealer did install a new Motorcraft battery and reset the software, so maybe that is the fix. Time will tell?

 

[Packer Bill]

Resetting my BMS did help my battery (Ecoboost not Hybrid) but time will tell. I still think it is a BMS (software) issue and it is killing our batteries.

 

[GhostMav]

Something doesn't make sense here,are you saying Ford put a new battery in under warranty,it's at the dealership, it won't start,and the dealership is saying nothing is wrong?

Yep. They already replaced the factory battery with a new one. 5 days later it was dead in my driveway once again. The battery drains to 0 overnight even after driving 40 plus miles home from work. Dropped it off 3 weeks ago and they say they can't find any cause after weeks of investigating. So, come pick it up and wait for Ford to send out a service bulletin (which everyone knows they will never ever do for this).

 

[Tim d]

Frustrating t

Yep. They already replaced the factory battery with a new one. 5 days later it was dead in my driveway once again. The battery drains to 0 overnight even after driving 40 plus miles home from work. Dropped it off 3 weeks ago and they say they can't find any cause after weeks of investigating. So, come pick it up and wait for Ford to send out a service bulletin (which everyone knows they will never ever do for this).

Frustrating to say the least! I'm curious if they use the same battery as my ecoboost maverick? It sits a week sometimes without being used and no issues.i live in upper Michigan so it gets cold.

 

[Silver23]

this is long but bear with me

on my 23 hybrid
dead battery overnight at least 3 times, I'm talking like 3 volts.
first dealer visit they charged and checked the battery and said it was ok.
next day deader than crap, they found a dealer add on alarm causing a draw, unplugged it and all has been good for months.

Now I have a little volt meter plugged into the consol. I watch it like a hawk. It always shows 14.7 to 14.9 volts when the truck is on so I know it is charging. The battery shows about 12.1 to 12.2 overnight. I know that battery is not so great because it was killed multiple times, but, it is good enough for the hybrid to start. If it would start an Eco boost I don't know. I don't have a load tester.

For all those with problems get a little volt meter for the acc plug. If it shows high 14 volts or more like 15 , IT IS CHARGING and the problem is a draw or bad battery.

My guess is most with problems have a bad battery, at least using a voltmeter you can eliminate a charging problem. I do not think is is possible for the truck to give say 15 volts to the battery and not give it amperage (if the battery is good and will take it), it's Ohms law
Bad batteries behave that way, you can give them charge voltage and they just won't take it. You may see a decent surface charge but that will quickly go away if it's bad.

Ford refused to give me a new battery, they said it was still good. I know batteries that have been discharged that much multiple times aren't so good. I will probably end up with an AGM before too long.

 

[skinnyboy]

Yep. They already replaced the factory battery with a new one. 5 days later it was dead in my driveway once again. The battery drains to 0 overnight even after driving 40 plus miles home from work. Dropped it off 3 weeks ago and they say they can't find any cause after weeks of investigating. So, come pick it up and wait for Ford to send out a service bulletin (which everyone knows they will never ever do for this).

Definitely the same thing I experienced, but your truck is doing it more often. My guess is a failing or out of spec. component, as if it was software only more of us would have the completely dead ones.

If Ford commits the resources to identify and address the issue it could potentially be addressed by a software update though. Fingers crossed.

Cheers.

 

[Silver23]

Yep. They already replaced the factory battery with a new one. 5 days later it was dead in my driveway once again. The battery drains to 0 overnight even after driving 40 plus miles home from work. Dropped it off 3 weeks ago and they say they can't find any cause after weeks of investigating. So, come pick it up and wait for Ford to send out a service bulletin (which everyone knows they will never ever do for this).

do yourself a favor and pull the cover at the passenger's feet. Look for any extra wires tied into stock wires. Mine had an alarm that a dealer put in and the thing began killing my battery overnight. Unplugged it and all has been good for months.
Just something to try...

 

[Skyline]

Band-aid on an arterial wound, unfortunately. This has been going on for years now and on many more vehicles than just the Mavericks.

Presumably, it's been going on since Ford added the the BMS to the charging system....

On the other hand, the BMS isn't the only system that impacts charging the battery:

BMS: Battery Monitoring System
BCM: Battery Control Module
PCM: Power Control Module

The BMS is only uploading the SoC/condition of the battery to the BCM. It is the function of the BCM/PCM to control the charging the battery, how long to charge, what voltage, etc. This system can stop the charging, if the truck is accelerate fast.

These are modules with their own PCB, chips and firmware. Do they always work as intended to? Most of the times they probably do, but when it comes to hardware/software, there's always a glitch somewhere. Most people's vehicle may not get to this "glitch" to the noticeable level, while others cannot get rid of the same. As such, it is really not easy to pinpoint the source of the issue.

I did noticed that on my Maverick the battery is charged for 15 - 20 minutes close to 15V, then it drops down to battery voltage. My trips are short at low speed, the charge probably would resume on longer trips.

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