HYBRID 12V Battery Mystery SOLVED

[Darryl]

You REALLY need to find the posts that show this is not a DCDC issue.
This is not a drain issue.

This is a purposeful strategy.

You could see it too with a scan tool monitoring some PIDs.

12V battery SOC%, and Amps (Battery2 for showing decimal value), and Volts.

You have a nice long drive into work.
If you do NOT have the headlights on, do NOT have the fan speed 6 or above, or NO trailer light - here's what several posters with the tools have reported already. With picture proof.

If your SOC% is good enough it's upwards of 90%, you'll be getting your float charge of below 1 Amp pretty quickly.
When it reaches 92% - you should start showing a Voltage of 12.8, and discharge from your battery, negative Amps.

Keep at that - and it'll discharge to mid 80's% SOC. Then float charge again to 92%.

Or, when at 92% and it starts discharging - turn on your headlights manually.
Now what happens to Amps and SOC%?

That's it.

Regarding what you think my issue is - it's the same issue many see that don't have a bad battery die overnight.

The BMS system using the battery sensor is reading ALL Amp hours going into and out of the battery.
And it sees balance.
If DCDC was undercharging - it would show less charge, more discharge.
And if I had short/partial discharge events from the ACCM or ABS - there would be more discharge then charge. Except if you drive long enough, it can recover.

Now - I do think I have a bad battery sensor and it's getting inaccurate Amps IN/OUT.
But I can't prove it - when I put a multimeter in DC Amp mode inline with the negative cable - the BMS must not see enough resistance or something - it drops to no Amp charge to the battery.
I cannot confirm Amps to see if the battery sensor is correct.
It does report the Volts under the true value, but that's better than reporting a higher than true value at least.

Since you have a long drive into work - you could probably do the above test during a lunch drive borrowing a scanner - you should be about as charged as you'll get.

To be honest, I'm simply going by results. If the vast majority of the hybrid Maverick batteries are lasting a normal life, that's what matters. There is a subset that have persistent frequent battery issues and short battery life and those are the ones that Ford is focused on. What's different between the majority with no issues vs the sizable minority with persistent issues.? The problem isn't likely something that's common to EVERY Maverick hybrid. It's most likely something that's occuring in the problem vehicles that isn't occurring in the non problem vehicles.

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[Red Eyes - Wide Shut]

To be honest, I'm simply going by results. If the vast majority of the hybrid Maverick batteries are lasting a normal life, that's what matters. There is a subset that have persistent frequent battery issues and short battery life and those are the ones that Ford is focused on. What's different between the majority with no issues vs the sizable minority with persistent issues.? The problem isn't likely something that's common to EVERY Maverick hybrid. It's most likely something that's occuring in the problem vehicles that isn't occurring in the non problem vehicles.

Just when I posted that my 2nd new battery had seemed to be holding up, l got a notice today. Sat for basically 1 day without driving. See the attached message of near death experience. It did start this time.

I'm going to drive cross country today. All to charge the battery as the app advised. LMAO......there goes the gas mileage due to required Ford Charge Driving......FCD requirements, a new Ford term.

 

[MakinDoForNow]

IIRC an AGM battery can be trickle charged back to better health but it can only be done very slowly (<3 amps with a dedicated trickle charger). At least, this was possible on the tiny battery in my used Miata a couple of decades ago.

Worth a shot in any case.

I have used a noco genius 5 to recover a 12 volt agm (small for polaris ranger) that was dead flat, voltage less than recognizable for 6 volt battery (2-3v?). Jumper to 12v battery for 10 seconds to get surface charge over 6v battery there window then put noco on at 6v charge and leave until charged and resting 24 hours to cool. Then switch to 12 volt battery charge setting and leave for one to two weeks. When noco in standby (solid green no orange/red charge level burning) disconnect neg post clamp and reconnect to restart noco every 2nd day until it cycles to standby in a short time. Took about SIX weeks total on my small agm. Am still using after 4-5 years old. Procedure will work on flooded also but be sure to go 6v then 12 v and using smart charger with temp selection. I have 2 200AH 6volt agm (in solar panel set) on a noco g10 which after several months will not rest above 6.1 for 4 days so may need to retire those $650+ puppies. Need to find some used from someone upgrading to newer sets!!!

 

[Waterick]

To be honest, I'm simply going by results. If the vast majority of the hybrid Maverick batteries are lasting a normal life, that's what matters. There is a subset that have persistent frequent battery issues and short battery life and those are the ones that Ford is focused on. What's different between the majority with no issues vs the sizable minority with persistent issues.? The problem isn't likely something that's common to EVERY Maverick hybrid. It's most likely something that's occuring in the problem vehicles that isn't occurring in the non problem vehicles.

An old normal battery life is what's keeping our 2014 Prius around. At 104k it's really just broken in for a hybrid and returning some of it's best MPG. My Maverick does not bode well even with today's accepted normal battery life, what maybe 4 years? Our Prius had its last 12v battery at three years old, but nothing needed since and gives no indication of degradation. What's the matter with today's carmakers?

 

[MakinDoForNow]

An old normal battery life is what's keeping our 2014 Prius around. At 104k it's really just broken in for a hybrid and returning some of it's best MPG. My Maverick does not bode well even with today's accepted normal battery life, what maybe 4 years? Our Prius had its last 12v battery at three years old, but nothing needed since and gives no indication of degradation. What's the matter with today's carmakers?

FOOCB!!!!
Fear Of Over Charging Battery!!!!

 

[HeyBales]

To be honest, I'm simply going by results. If the vast majority of the hybrid Maverick batteries are lasting a normal life, that's what matters. There is a subset that have persistent frequent battery issues and short battery life and those are the ones that Ford is focused on. What's different between the majority with no issues vs the sizable minority with persistent issues.? The problem isn't likely something that's common to EVERY Maverick hybrid. It's most likely something that's occuring in the problem vehicles that isn't occurring in the non problem vehicles.

Don't start with 2025MY that came with AGM. Those are only getting to 2 yrs old.
Start with pre-25 that came with SLA.

What's a normal life?
5-7 years? For me and many other posters, even on prior vehicles that had some smarts to it and micro-drains that were expected.
You are not even reaching that many years yet to know.
Some are reaching 4 yrs - and with a battery out of warranty - are they coming in for Ford to have stats?

And I gave the list in prior post why you'd never see them in the shop so far.

Plus - I doubt greatly you'd be hearing about the batteries coming in that finally tested low enough to be swapped out.
Because they did NOT have a battery drain - they drove in, 2nd or 3rd time, complaining about no lights or remote start. And finally battery tested bad enough for warranty swap.

 

[okgaz]

To be honest, I'm simply going by results. If the vast majority of the hybrid Maverick batteries are lasting a normal life, that's what matters. There is a subset that have persistent frequent battery issues and short battery life and those are the ones that Ford is focused on. What's different between the majority with no issues vs the sizable minority with persistent issues.? The problem isn't likely something that's common to EVERY Maverick hybrid. It's most likely something that's occuring in the problem vehicles that isn't occurring in the non problem vehicles.

I hear you and totally agree with the sentiment on most things - the loudest voices are those upset / no one goes out of their way to say things are fine.

But I would disagree that’s it’s statistically a “minority”. Battery issues are prevalent with the model based not just on the many user complaints but also Ford’s own communication, including service bulletins; dealer feedback; service suggestions to replace; etc.

Where there’s (that much) smoke, there’s fire.

That doesn’t mean the truck is flawed. It means the components were not matched property - that is likely due to the need to produce quickly and cheaply.

And the conclusion you came to could be seen from the other side - just because some vehicles get away with no having no visible issues, does not mean a manufacturer issue is not present in all. There seems to enough data to support this.

 

[Mavster Mechanic]

To be honest, I'm simply going by results. If the vast majority of the hybrid Maverick batteries are lasting a normal life, that's what matters. There is a subset that have persistent frequent battery issues and short battery life and those are the ones that Ford is focused on. What's different between the majority with no issues vs the sizable minority with persistent issues.? The problem isn't likely something that's common to EVERY Maverick hybrid. It's most likely something that's occuring in the problem vehicles that isn't occurring in the non problem vehicles.

So what makes a problem vehicle?

Ones built on Mondays with half the crew hung-over?

 

[SafetyGuy]

So what makes a problem vehicle?

Ones built on Mondays with half the crew hung-over?

I had one of those and it was a 2004 Jeep Liberty...what a nightmare.

Andy

 

[HeyBales]

I had one of those and it was a 2004 Jeep Liberty...what a nightmare.

Andy

Was this the sign hanging above the production line?

 

[Darryl]

Just when I posted that my 2nd new battery had seemed to be holding up, l got a notice today. Sat for basically 1 day without driving. See the attached message of near death experience. It did start this time.

I'm going to drive cross country today. All to charge the battery as the app advised. LMAO......there goes the gas mileage due to required Ford Charge Driving......FCD requirements, a new Ford term.

PLEASE get the ABS and ACCM updates done and share with us if it worked short and long term. I don't know if anyone has had the most recent updates performed to see if they actually work. Right now we're debating what we think will or won't work

 

[SafetyGuy]

Was this the sign hanging above the production line?

I wish it had only been a regular monday junk assembly by some...professionals..but it wasn't.

It stalled and coasted to the side of the road on the 10 mile drive home and all went downhill from there.

We did love it when it worked of course.

Just thinking that absolute piecs of low-quality manufactured abomination is making my wallet feel lighter.

But it sure looked good when it went by behind a tow vehicle, heading to our then local Dodge Chrysler Jeep dealer for another round of demon removal!

Come to think of it now, it had a sunroof...had to have the whole thing replaced as well after it flipped on its side (its favourite resting position)...I now detest sunroofs with every Fibre of my being.

Still makes me laugh, though.

Andy

 

[Finnster]

IIRC an AGM battery can be trickle charged back to better health but it can only be done very slowly (<3 amps with a dedicated trickle charger). At least, this was possible on the tiny battery in my used Miata a couple of decades ago.

Worth a shot in any case.

Just saw your post!
I started recharging the 12V battery about an hour ago with my Noco 1, GMTA. "great minds..."

 

[Finnster]

I'd bet you are getting the float level charge up to 92% SOC. But never reaching it.
Before you were getting the higher charge to get up to 88%. But didn't go over.

What has your morning resting Voltage been?
I know, you gotta turn on then off quickly, so a tad bit of charge - but still.

Sorry, I missed the resting voltage this morning - Damn!
However the initial charge voltage was 14.8 volts (ready/run mode).
After a short trip to town and back today (16 miles each way W/ 30 minute stop), Indicated voltage shown: 14.7V.
After 1 hour rest, Battery tester showed 95% 12.61V.

Additional information: Three days ago after my non-stop 40ish mile drive @ 70mph and at 90F deg. air temperature. My indicated charge voltage was sitting at 14.1V, indicating to me that this long (my longest ever in the Mav) drive had finally fully charged my wounded AGM battery.
This is the drive that returned 37mpg!

For comparison, todays highway miles returned an average of 36.5mpg indicated - Resetting the Economy screen to zero, once 70mph (72F deg. air temp.) was obtained, and recording the gas mileage upon hitting the highway exit. (highway-only mpg reading).
For the record, My trip into town today was done with the trailer hitch brake light installed! There was no change in result from my "no hitch brake light" trip to town yesterday. IMO this still points to my truck's 12V battery charging gremlins being fixed from the trailer module update.

I am recharging the 12V battery tonight just to see what effect that has on charging voltages. I don't know yet if I will use the Mav tomorrow or not.

 

[Finnster]

I'd love to know what the resting voltage on those successful trucks is.
And what the Ford self reported SOC% is.
After say 2 and then 4 weeks. Shoot - 2 and 4 months!

Because this thread is proving there is an undercharging strategy that can be defeated when the battery is at least newer and fresher, or all charged up externally.
And has nothing to do with a battery drain that is intermittent and unrecoverable.

I can show you log files from my truck proving that the BMS system believes it has equal amp hours charging and discharging.
There is no heavy drain that isn't met by a heavy charge for a few days or a long drive - I mean 8-10 amps for 10-15 min, then slowly dropping, but not as fast as normal.
And yet despite that - the resting voltage is down at 11.8-12.0 very easily, because at the start it was willing to let it drop.

The problem is Ford is still only chasing intermittent parasitic drains - that's great and needed.
But the number of people on here reporting such is actually very infrequent as you read many posts.
Meaning the battery is dead in a day or two. Or maybe it got mostly drained because the drive the next day interrupted the intermittent part, and it didn't come back to finish the drain.
The number of people on here reporting just a low voltage battery is very frequent.
Their system is willing to live with battery saver on - even without deep sleep mode. So 12.1V or less.
How many more have no issues and totally charged up battery?
Some have reported no battery saver alerts or lights off early. Even with infrequent brief drives. And cold winters. Incredible.
This thread proves there could easily be reasons why some never seem to have a problem.

Also need to distinguish I think between pre-25MY where there is no comment in the manual about battery specs being matched.
But the 25/26 manual does say the same thing the EB section says - use the exact same spec battery, or have a technician update the BMS figures for the battery. Seems Ford made a change there.
That's probably where that AGM option makes a difference. 25/26MY.
Posters have changed that value way back on pre-25MY and reported it made no difference when they got an AGM - still had problems shortly, didn't change the charging strategy.

And no - my dealer won't do the ACCM update unless I come in with drained battery. Waste my time at another dealer with no truck for hopefully only 2 days if they do it - no thanks.
My slowly being killed battery doesn't seem to count.

Sorry if this is coming off harsh - but I keep seeing this disconnect between 2 different problems.
And I'm always posting about someone checking on the ACCM update when they report a drain condition.
But this thread is the first time something has been found to force higher charging to keep a battery from getting undercharged and slowly go bad.
It's not doing that because there was a parasitic drain, just the normal micro-drain.

@HeyBales, Sorry for resurrecting this post from page 13 of this thread, but I have a theory that I would like to have you consider!
I don't have the tools, time or patience to pursue it, but you always seem game!
My theory pertains to this statement of your's:
"Sorry if this is coming off harsh - but I keep seeing this disconnect between 2 different problems.
And I'm always posting about someone checking on the ACCM update when they report a drain condition.
But this thread is the first time something has been found to force higher charging to keep a battery from getting undercharged and slowly go bad.
It's not doing that because there was a parasitic drain, just the normal micro-drain."
[/QUOTE]

I agree! Two completely separate and battery damaging parasitic drains!

My theory (which I can in no way prove or defend):
These two parasitic drain happen independently and at different times.
One of these, the conventional parasitic drain comes upon vehicle shutdown and drains the battery! Ecoboost and/or hybrid - makes no difference.
The other parasitic drain, the one that happens as soon as the (mostly? hybrids) vehicle is turned on - causing the DC to DC converter to kick into action!
This parasitic draw is huge! Enough to drop my 2025XL's 70mph gas mileage from the 36 -37mpg I am currently seeing, down to the 30mpg I was getting before the trailer module update!
The trailer update has fixed this huge parasitic draw! Just like the ingenious "headlights on, wipers on, parking lights on, rear seat 120V outlet usage, and hitch brake light on" hack has been shown to circumvented this same parasitic draw!

The TMU came too soon for me to test whether the hitch light etc. would have increased my highway mpg, in addition to normalizing my 12V battery charging!
I hope someone who hasn't had the TMU yet can test that.

How can a parasitic huge drain reduce gas mileage?
Easy, the motor generator has to work at essentially 100% output (for it's given engine speed?) to satisfy the parasitic electrical drain.

Why doesn't the battery get charged?
Likely, the vehicle's electrical systems' "need" has first dibs on the electrical power supplied by the DC to DC converter, so the battery gets starved...Until higher speeds and longer drives allow the motor generator to finally supply enough electrical supply to satisfy both vehicle needs and battery charging!

That's it!
I'll entertain questions, but it is unlikely that I will be to answer any of them! What we need (I think) is a hybrid vehicle electrical design engineer.

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