Hybrid 12 Volt Battery Crazy Findings

[rslilly76]

I'll guarantee that when a solution is found, there will be people who never get it because their dealerships techs don't stay current or they will argue with a Ford tech that tells them Ford has a solution (a new software update) that works for the vast majority of vehicles and tell him that he's wrong. Ford has issued an updated software patch that can't be done over the air because of the procedure that's used. But I'll bet that some who have vehicles still under warranty won't take them in to have the update performed. Seems like I'm yelling into a void

Well how about this one, I went to 3 dealerships and they wouldn't even do a software update on my truck cause they were like if you're not having issues we're not updating it. However, Ford put the update out for my build specifically! I had to get OTA division involved. When I found a dealership that would do the update they realized there were 12 updated needed. My OTA wasn't doing what it should, so they fixed that too. So tell me again how people won't do the updates when you can't even get the dealerships to do them.

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[rslilly76]

Ok parked the truck at 97% last night, and set parking brake. This morning 97%

The previous night 99% no parking brake and 94% yesterday morning.

 

[CaptRedBeard92]

Really interesting post! I am curious if there is any difference in the 2025 trim levels, or maybe the manufacturing date.

I have been watching a basic voltage meter (cig lighter) for the last 12000 km and have never seen the voltage go below 14 volts while driving. Usually it is between 14-15 V. It usually starts higher and drops down to the lower value after driving for a bit. This is the 2025 Hybrid AWD Lariat, late 2025 build date. No change at all switching on headlights or towing a trailer with lights, I have been trying for many weeks to replicate this behavior others are seeing.

I suppose I am lucky, and won't complain

When the truck is turned off, voltage settles around 12.6 to 12.8. I do drive often, so perhaps I havent seen a low enough SOC to create some of these problems.

Fun fact I haven't seen elsewhere: the HVB and DC/DC converter are actually running in accessory mode, and will power accessories if there is enough charge available. The voltage will drop over time and eventually draw on the 12V with enough time.

 

[rslilly76]

The first picture is with my headlights on (it's daytime here) and the battery is 99% SOC, Battery voltage is 14.05v, the charging amps are 1.56A (trickle charge) and the DCLVA is 33A due to the truck's needs.

The second picture when I started my vehicle you can see the truck went into immediate discharge of the battery and headlights are off. SOC is 98%, battery voltage is 12.8v, charging amps are -8A, and the DCLVA is 40A due to the truck requiring that much to run the 12v system.

(See how the dc/dc converter is supplying more Amps, but the truck isn't charging the battery but instead it is draining the battery on purpose. Once I turned on the headlights the battery started to charge.)

Just FYI I also changed the maximum state of charge from 80% to 95% in Forscan, and this did not change anything at all to how the truck performs on charging the AGM battery.

Anyway, I thought this was good info for people out there, and if anyone wants to test theirs they know more about how to do it.

I am using Car Scanner Pro (it's like $8 for a lifetime membership)
I am using Vgate vLinker BT OBD2 scanner from Amazon

Really interesting post! I am curious if there is any difference in the 2025 trim levels, or maybe the manufacturing date.

I have been watching a basic voltage meter (cig lighter) for the last 12000 km and have never seen the voltage go below 14 volts while driving. Usually it is between 14-15 V. It usually starts higher and drops down to the lower value after driving for a bit. This is the 2025 Hybrid AWD Lariat, late 2025 build date. No change at all switching on headlights or towing a trailer with lights, I have been trying for many weeks to replicate this behavior others are seeing.

I suppose I am lucky, and won't complain

When the truck is turned off, voltage settles around 12.6 to 12.8. I do drive often, so perhaps I havent seen a low enough SOC to create some of these problems.

Fun fact I haven't seen elsewhere: the HVB and DC/DC converter are actually running in accessory mode, and will power accessories if there is enough charge available. The voltage will drop over time and eventually draw on the 12V with enough time.


Really interesting post! I am curious if there is any difference in the 2025 trim levels, or maybe the manufacturing date.

I have been watching a basic voltage meter (cig lighter) for the last 12000 km and have never seen the voltage go below 14 volts while driving. Usually it is between 14-15 V. It usually starts higher and drops down to the lower value after driving for a bit. This is the 2025 Hybrid AWD Lariat, late 2025 build date. No change at all switching on headlights or towing a trailer with lights, I have been trying for many weeks to replicate this behavior others are seeing.

I suppose I am lucky, and won't complain

When the truck is turned off, voltage settles around 12.6 to 12.8. I do drive often, so perhaps I havent seen a low enough SOC to create some of these problems.

Fun fact I haven't seen elsewhere: the HVB and DC/DC converter are actually running in "accessory mode", and will power accessories if there is enough charge available. The voltage will drop over time and eventually draw on the 12V with enough time.
[/QUOTE]
I used the cigarettes lighter 12v adapter too prior to testing with car scanner pro. Trust me your vehicle is under 92% if that cigarette lighter is showing 14+ volts while running

 

[HeyBales]

Really interesting post! I am curious if there is any difference in the 2025 trim levels, or maybe the manufacturing date.

I have been watching a basic voltage meter (cig lighter) for the last 12000 km and have never seen the voltage go below 14 volts while driving. Usually it is between 14-15 V. It usually starts higher and drops down to the lower value after driving for a bit. This is the 2025 Hybrid AWD Lariat, late 2025 build date. No change at all switching on headlights or towing a trailer with lights, I have been trying for many weeks to replicate this behavior others are seeing.

I suppose I am lucky, and won't complain

When the truck is turned off, voltage settles around 12.6 to 12.8. I do drive often, so perhaps I havent seen a low enough SOC to create some of these problems.

Fun fact I haven't seen elsewhere: the HVB and DC/DC converter are actually running in accessory mode, and will power accessories if there is enough charge available. The voltage will drop over time and eventually draw on the 12V with enough time.

Interesting fact - it's hard to get the push-button start systems into TRUE Accessory mode.
If your HVB is engaged - you are in On mode, not Accessory.
When you push the Start button with no brake - On mode.
HVB is engaged as you've seen.

When the HVB SOC reaches 30%, charging the 12V battery and system is disengaged.
Now the 12VB is powering all the modules - it'll drop quick. Eventually the BMS will turn truck off when that gets low enough.
Must Start truck. ICE will kick on, HVB has to get to 40%, then ICE will turn off and charging the 12VB is back.

Keyed ignition is easy - Off - Accessory - On - Start (back to On).
Push button you have to Start with brake, then Off without brake. Quickly if you want a morning Volt reading with some accuracy.
That will give quick Voltage reading on power port adapter without much charge actually being added.

Oh - if you are seeing an inflated Voltage of 12.6-12.8 after driving and charging - you can bet you started much lower.

That's the reason why you never see below 14.x - battery charge is not high enough to reach 91% SOC to drop the charging and show 12.8 V.

This method would probably work if you externally charged your battery once to get it high enough. Then the moment you saw 12.8V, fan to spd 6 or headlights on.

So yours is likely already in the upper 80's% SOC, since you drive more.

 

[HeyBales]

I'll guarantee that when a solution is found, there will be people who never get it because their dealerships techs don't stay current or they will argue with a Ford tech that tells them Ford has a solution (a new software update) that works for the vast majority of vehicles and tell him that he's wrong. Ford has issued an updated software patch that can't be done over the air because of the procedure that's used. But I'll bet that some who have vehicles still under warranty won't take them in to have the update performed. Seems like I'm yelling into a void

I'd suggest plenty of us have TRIED to get the intermittent parasitic battery drain software updates just in case it might help our purposely undercharged battery situation.
Even though we never had a drained battery some morning.

But unless we came in with an actually drained battery - ie dead battery - they aren't doing it.
Some may, while doing other things with the vehicle, like replacing a 1 yr old battery that never had a intermittent parasitic drain.
But rather was just undercharged for too long and went "bad".

1 issue.
1 purposeful design choice I'd bet most don't agree with. We call it an issue.
The design will make the issue worse.
But they aren't related.

 

[Cherokee]

I wasn't offended at all, and as far as forum fixes we suggested try the 4 different methods and see if the battery charges to full capacity

Roger that but in my 17 months of Ecoboost ownership Ford has done nothing to actually fix this low 80% state of charge I max out at.
I know it’s going to kill my AGM sooner than is necessary.

And countless forum members have,
‘Claimed to have a fix.
But it seems that’s not true.
They may make it a little better but no one has actually fixed anything.

I’m pissed at Ford for allowing this problem to go unsolved.

Other manufacturers have been doing Hybrids for a very long time without problems.

 

[rslilly76]

Roger that but in my 17 months of Ecoboost ownership Ford has done nothing to actually fix this low 80% state of charge I max out at.
I know it’s going to kill my AGM sooner than is necessary.

And countless forum members have,
‘Claimed to have a fix.
But it seems that’s not true.
They may make it a little better but no one has actually fixed anything.

I’m pissed at Ford for allowing this problem to go unsolved.

I'm pissedd at Ford too as a lot are. But if you try it then it adds to our case if it works

 

[rslilly76]

Ok parked the truck at 97% last night, and set parking brake. This morning 97%

The previous night 99% no parking brake and 94% yesterday morning.

obviously not a consistent thing
parked truck with brake everytime
this morning 89%

 

[Mavster Mechanic]

I'll guarantee that when a solution is found, there will be people who never get it because their dealerships techs don't stay current or they will argue with a Ford tech that tells them Ford has a solution (a new software update) that works for the vast majority of vehicles and tell him that he's wrong. Ford has issued an updated software patch that can't be done over the air because of the procedure that's used. But I'll bet that some who have vehicles still under warranty won't take them in to have the update performed. Seems like I'm yelling into a void

What does warranty period have to do with this? Software does not wear out based in time or miles.

 

[HeyBales]

obviously not a consistent thing
parked truck with brake everytime
this morning 89%

That likely just has to do with how the SOC% is calculated.
Most of us know the SOC tables - this voltage = this SOC%.
That's a resting voltage though - 4 hrs no charge or drain (at least mA ain't much).

SOC% while driving can't be based on voltage of course - that's where the cumulative figures at minimum come into play - counting Ah in & out. Solar been doing it for years, as well as BMS systems.
So I'm sure the purely calculated value when we stop is adjusted to another calculated value after a long enough rest, and hopefully Volts is part of it - but I've seen the same 11.8V resting show as some wildly different SOC from 48-57%, I'm convinced it's not a table lookup then.

 

[cthlyte]

It's crazy, I have never had these issues and I have owned my 25 hybrid Maverick for over a year. Even sitting at an airport for a week, I still got in and it fire right up.

To note, I have it auto start every week day, but not on weekends when I drive it less or not at all.

 

[UncleMatt]

Well thanks to @HeyBales and @Mavster Mechanic I have gone down a rabbit hole with the whole 12v battery issues in the Hybrids. Thanks guys! LOL

So I will start off with an old ICE and a 12v battery to help educate anyone that needs it. That setup typically consists of a 12v battery that will power lights, radio, starter, etc. until the engine is started. At this point in time the alternator is supposed to take over powering everything. The battery sitting idle not being used should read 12.6 - 12.8v typically. This goes for a standard lead acid battery or as some people call a flooded battery. It also holds true for an AGM battery (you can research batteries yourself). When the alternator takes over the battery typically reads 13.5 - 14.5 voltage because the alternator is charging the battery. The regulator on the alternator typically adjust based on what all is being used on the 12v system of the vehicle, and adjust accordingly. The idea is to charge the battery to 100% at which point the alternator will adjust the regulator to not overcharge the battery. FYI most alternators provide 1 - 50amps of charging to a 12v battery depending on the need. This is why if you don't drive much batteries die prematurely cause they never reach full 100% charging capacity.

A quick google search will tell you that 12v SLA or 12v AGM battery should be at 100% charge and avoid being drained for prolong periods to ensure the maximum life of the battery. If you look at standard battery chargers they go from 1 amp - 75 amps. 1 amp being a trickle charger and 75 amp being a very fast charger. (you will see why I bring this up momentarily).

So Ford has stated that the deep sleep issues on the Hybrid model Maverick is due to parasitic draw and needing revised software. Which don't get me wrong, I think that is one part of the problem for sure. Two very known software updates are the ACCM update and the ABS update that is supposed to resolve the deep sleep battery issues everyone is having. However, none of these actually fixed the problem as you can search forums and also FB groups and see tons of 12v battery issues on the 22-25 Mavericks. (I am assuming nothing has changed on the 26, but I guess we will see).

Ford's initial fix before software upgrades was moving from an SLA battery to AGM battery, but that didn't fix anything because essentially these batteries both work the same. The AGM has slightly better stats and reserve time. Many people saw this fix and decided to upgrade to a bigger AGM thinking that this would solve the problem. Keep in mind the thought was the parasitic draw was the problem, and by going to a bigger AGM essentially they were buying more reserve time on the battery. A noble train of thought and a good idea, but it literally isn't solving the problem to this date.

Another train of thought was to use Forscan and increase the maximum charge setting of the 12v from 80% to 95%, why not change it to 100%? I have no idea everyone's train of thought on this, but some users reported this fixed their problem. There was never any real testing that showed or that I saw anywhere that confirms this actually does anything to fix the problem.

Now fast forward to @Mavster Mechanic findings. This one threw me for a loop until I started testing. There is a whole thread with lots of good reading material if you want to go down this rabbit hole. He is way more versed and way more knowledgeable in this matter and I suggest you read his findings. https://www.mavericktruckclub.com/forum/threads/hybrid-12v-battery-mystery-solved.81553/

I will try to summarize the findings. The 12v SLA battery will charge to 85% and a 12v AGM battery will charge to 92% in the Hybrid. At this point and time some programing in the vehicle tells the DC/DC converter to stop charging the battery and actually the 12v battery starts draining at this point and time. I don't mean draining naturally, I mean the vehicle starts draining the battery on purpose. However, if you do one of these things you can make the vehicle start charging the battery again until the battery hits full charge of 100%. (1. turn on the headlights, 2. turn on the parking lights, 3. turn the hvac fan to 6 or 7 speed, 4. plug in trailer lights). If you do one of these four things, it doesn't matter which one of the four methods, the vehicle turns the charging back on to the 12v and will actually let the 12v charge to 100%. Now keep in mind if you charge the battery to 100% the minute you start the vehicle again it will go into drain mode again because it's over the 85% for SLA or 92% for AGM.

Now while I will agree with parasitic draw being an issue that will drain the 12v battery, I also believe not allowing the 12v battery to be at 100% more times than not also contribute to a battery failing prematurely. Reading all the forums and FB posts you will see it doesn't matter if it is SLA, AGM, or even a bigger battery these batteries are failing prematurely because of the programming of how it charges mixed with parasitic draw. The people that aren't having these problems with theirs, I wonder how many of them pull trailers, drive a lot a night, have the ac or heater on high a lot, or turn their parking lights on to be seen in traffic?

Think about it like this, your battery is only 80% charged will typically read 12.5 volts while a battery at 100% reads 12.6-12.8. You leave the vehicle parked for a week when it's 100% charged and come back it's been drained to 80% because of parasitic draw and now the vehicle still starts. But if you leave an 80% battery for a week and because of parasitic draw it's down to 60% and won't start.

It's really perplexing to me why Ford wouldn't allow the battery to charge to 100% no matter what the conditions are if the vehicle is running, but I am not a Ford engineer. You would also think that they would want to come up with a solution to prevent class action, or loosing customers in general. Plus I can't imagine how much has been spent on this issue from Ford's perspective.

So now I will show my screen shots and try to describe what you are seeing.
12v SOC = 12 volt battery state of charge
Vehicle B battery Voltage = 12 volt battery reading in volts
Vehicle B battery Current = 12 volt battery amps (the amount of charge being sent to battery)
DCLA = DC/DC converter amp output to the 12 volt system of vehicle (this is like your alternator powering everything in the vehicle while running)
12 v battery quiescent avg = this is how much parasitic draw is while the vehicle is off

So to give you an idea my truck is a 2025 Hybrid fwd XL. It has had all the software updates by Ford including ACCM and ABS. It has an AGM battery from Ford OEM. My parasitic draw is between 12 - 18 mA which if you look up on google is outstanding for any vehicle 12 volt discharge while the engine is off.

The first picture is with my headlights on (it's daytime here) and the battery is 99% SOC, Battery voltage is 14.05v, the charging amps are 1.56A (trickle charge) and the DCLVA is 33A due to the truck's needs.

The second picture when I started my vehicle you can see the truck went into immediate discharge of the battery and headlights are off. SOC is 98%, battery voltage is 12.8v, charging amps are -8A, and the DCLVA is 40A due to the truck requiring that much to run the 12v system.

(See how the dc/dc converter is supplying more Amps, but the truck isn't charging the battery but instead it is draining the battery on purpose. Once I turned on the headlights the battery started to charge.)

Just FYI I also changed the maximum state of charge from 80% to 95% in Forscan, and this did not change anything at all to how the truck performs on charging the AGM battery.

Anyway, I thought this was good info for people out there, and if anyone wants to test theirs they know more about how to do it.

I am using Car Scanner Pro (it's like $8 for a lifetime membership)
I am using Vgate vLinker BT OBD2 scanner from Amazon

Thanks for the extensive note on your issues. I had my 12volt battery die, mid winter, without warning. So I replaced it with an AGM battery from Ford.

My comment is nerdy, and may not be pertinent to the solution. But my understanding is that the Maverick Hybrid does not include an alternator. That the 12v battery charging comes from the "big battery" by way of a DC to DC convertor. Not a traditional alternator.

Here is a link that perhaps says it better:
https://www.mavericktruckclub.com/f...lternator,,power the standard 12v electronics.

I have long-standing interest in dead batteries, and the pain and misery that ensues. I was under the impression that this hybrid (like a Toyota hybrid) would not have this issue. But, it does not completely insulate us from non-starting vehicles.

Good luck with all that. If you learn anything more, please pass it along.

I am not diving into Forscan or whatever. The truck/car should just work, without me dickering with it.

 

[Mavster Mechanic]

Thanks for the extensive note on your issues. I had my 12volt battery die, mid winter, without warning. So I replaced it with an AGM battery from Ford.

My comment is nerdy, and may not be pertinent to the solution. But my understanding is that the Maverick Hybrid does not include an alternator. That the 12v battery charging comes from the "big battery" by way of a DC to DC convertor. Not a traditional alternator.

Here is a link that perhaps says it better:
https://www.mavericktruckclub.com/forum/threads/hybrid-alternator.11178/#:~:text=In place of an alternator,,power the standard 12v electronics.

I have long-standing interest in dead batteries, and the pain and misery that ensues. I was under the impression that this hybrid (like a Toyota hybrid) would not have this issue. But, it does not completely insulate us from non-starting vehicles.

Good luck with all that. If you learn anything more, please pass it along.

I am not diving into Forscan or whatever. The truck/car should just work, without me dickering with it.

Agree it should just work.
But if it doesn't, which is the lesser of two evils:

Dickering with your truck
Or
Dickering with a Ford Dealership?

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