HYBRID 12V Battery Mystery SOLVED

[HeyBales]

This thread is now 27 pages long so I am wondering what i record for longest thread is, if not this. I have 2 $32,000 questions....

1. Does Ford monitor this board?
2. If the answer is yes, is this topic active there and what are they doing about it?

They stepped out being active on the forum couple years ago - and that was limited even then to the media monitor having any influence on a local dealer.
Some reports were positive, others nada.

Private monitoring - probably. Actionable - maybe.

Since this effect appears purposeful as to where they want the battery SOC - kinda hoping they don't notice this and discover they left a few methods that go beyond.

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[Mavster Mechanic]

This thread is now 27 pages long so I am wondering what i record for longest thread is, if not this. I have 2 $32,000 questions....

1. Does Ford monitor this board?
2. If the answer is yes, is this topic active there and what are they doing about it?

A) some have over 1000 messages. The daily meme one I think is the record. Over 9,000 messages

1. Probably in secret. But they won't respond.
2. Between little and nothing.

 

[Mavster Mechanic]

More evidence the truck does whatever the hell it wants.

Today: 50 minute 40 mile drive.
Daylight. DRL on but no other "tricks".

Ambient 58°F

After 1 minute of some negative and some positive 12v amperage it settled on this. And stayed like this (zero, or below 0.5 and rounded down) for the next 49 minutes.

I'm confused. Don't know whether to laugh or cry. But I'm starting to get bored with this...

 

[rslilly76]

More evidence the truck does whatever the hell it wants.

Today: 50 minute 40 mile drive.
Daylight. DRL on but no other "tricks".

Ambient 58°F

After 1 minute of some negative and some positive 12v amperage it settled on this. And stayed like this (zero, or below 0.5 and rounded down) for the next 49 minutes.

I'm confused. Don't know whether to laugh or cry. But I'm starting to get bored with this...

so crazy question, what if you set the drl to parking lights in forscan?

would it possibly fool it into thinking the parking lights are always on?

 

[Glen Baker LLC]

This thread is now 27 pages long so I am wondering what is the record for longest thread is, if not this. I have 2 $32,000 questions....

1. Does Ford monitor this board?
2. If the answer is yes, is this topic active there and what are they doing about it?

Sam,
Question # 1. No not officially.
Question #2. 27 Pages ain't even close.

 

[HeyBales]

So besides monitoring morning voltage direction, the power plug volt reading seems like one other good use.

@Mavster Mechanic

Would the simple use be:
While driving & none of the 3 systems are enabled, if you see 12.8V - the BMS has charged as high as it normally would (85% SLA, 92% AGM) and likely be in discharge state.
Turn on 1 of the 3 systems so it says 14.x again. (Amps lowered at 100%, but Volts stay high?)
May get by with a couple hours a week of that extra charge method.


@rslilly76
Great test and confirmation.
Ya - isn't the drop to float amps crazy. Fits with idea a battery charger final time is low amps - except they don't know how much longer we are driving.
Mine even at 50% SOC, within 5 minutes usually down to 1.x A, by 10 min <1.x float charge.

Thanks so much for confirming they kept the method going with 25MY and AGM battery.


Now we need a tester that has kept their SLA going strong thru regular recharging - with access to a scan tool - or at least the day after charging, notice that effect on a power port volt reading.

And no - my SLA isn't going strong, a recharge won't make it strong - and I want the warranty AGM before the 3yrs.

 

[Darryl]

I'm wondering if Ford programmers are more clever than people give them credit for.

If the "set point" was either 80% or 90%, but they also knew headlamp use would top off above this; then batteries would get occasional top offs as people naturally occasionally drive with headlamps on.

Maybe all / most battery issues happen to people who rarely drive at night. And MAYBE Ford has learned not to assume all people do?

The battery level has been sufficient for hybrids and conventional vehicles since they started using a battery life monitor. It's only been a consistent problem in some of THESE vehicles. So the charge level evidently isn't the problem. The Maverick is the problem given the fact that the problem is largely absent in the very similar Escape hybrid . I suspect it's a hardware issue that Ford is trying to program around because the escape and Maverick likely use similar components but possibly minor differences in some internal components

 

[rslilly76]

Well after yesterday's findings I decided to charge up the battery at home. I have a cheap old everstart 6amp charger, and I put the vechicle on that, but by the time I was ready to go to sleep it wasn't fully charged. I unplugged it anyway and this is what I found out today.

Started vehicle SOC said 98% and immediately the truck started to drain the battery with the negative amps showing on the BCM, and battery voltage to 12.8. I turned on the headlights, and it moved to 14.1 volts and the amps went up to 1amp. I drove for about 30 minutes to my first client and everything pretty much stayed the same, but the amps were down to about .5-.6 by the time I got to the client.

Next client I travelled to with the headlights on the amps went up 4-6 the whole way there and the battery reached 99% SOC

Next client it was back to 1 amp and 99% SOC.

This cycle repeated back and forth with each client 1amp one trip 4-6 amps the next trip. And there really was no rhyme or reason for the discrepancy accept that I turned the vehicle off and then back on.

Here's what I don't get, on SLA they start draining at 85% on AGM they start draining at 92%. Why aren't they allowing it to charge to 100%? SLA and AGM are supposed to be charged to 100% it prolongs their life. I know the Hybrid Lithium battery is a whole different story and that's why they shoot for 40-70% on those to extend their life.

Old school alternators would take over the 12v system while the vehicle was running, and they would charge the battery at around 13.5 - 14.5 volts to 100% (The only time a 12v battery would discharge when running was if the vehicle alternator or alternator regulator failed).

Why didn't ford design the dc/dc charging to mimic that? Are they trying to sell more 12v batteries by them prematurely failing on us? I just don't get it!

I think I am about to by a noco genius 5 and put the vehicle on it about 1 time a week at night or weekend.

 

[rslilly76]

The battery level has been sufficient for hybrids and conventional vehicles since they started using a battery life monitor. It's only been a consistent problem in some of THESE vehicles. So the charge level evidently isn't the problem. The Maverick is the problem given the fact that the problem is largely absent in the very similar Escape hybrid . I suspect it's a hardware issue that Ford is trying to program around because the escape and Maverick likely use similar components but possibly minor differences in some internal components

Here's the problem with that statement. The 12v battery is actually being drained while the vehicle is running. SLA starts draining at 85% and AGM starts draining at 92%. In no way shape or form should this ever happen unless the DC/DC converter fails and the truck needs to run on 12v battery alone. However, the vehicle is programmed to do this and does it consistently! The only workaround to prevent the 12v from being drained by the vehicle while running is the workarounds in the post. (headlights, park lights, fan at 6 or 7, or trailer light wired in)

Think of it like a gasoline engine with an alternator. The alternator runs the truck while the vehicle is running. In the process it charges the battery to 100% (provided you are driving it enough). The battery only get's drained starting it, or if you use the accessories without the vehicle running. (The vehicle has accessories that run while car is off too.

If an SLA or AGM battery isn't topped off to 100% you actually kill the life of the battery, you can do a simple google search and read up on 12v batteries for vehicles and see this is true. (Totally different mindset on Lithium batteries but I will let you research that yourself too).

We can't speculate on Escapes unless someone has an Escape Hybrid and would like to verify the same testing as we have been doing here.

Yes it has been consistent with some vehicles you are correct, but it's a programming issue. Ford keeps looking at parasitic draw thinking that's the case. (I am sure that is one part of the problem) However, this charging scheme is a big deal that will deplete a SLA and AGM battery prematurely and have the same affect as the parasitic draw.

My truck had the ABS and ACCM module updated back in May of 2025 (I bought it April 2025, and it was built Jan of 2025). It has an AGM battery stock from Ford, my parisitic draw is very minimal at 12-18mA but my truck is still programmed to drain the battery at 92% and not let it charge any further. My truck is typically between 80% - 90% due to all the driving I do, but this will prematurely kill the battery.

 

[Darryl]

Here's the problem with that statement. The 12v battery is actually being drained while the vehicle is running. SLA starts draining at 85% and AGM starts draining at 92%. In no way shape or form should this ever happen unless the DC/DC converter fails and the truck needs to run on 12v battery alone. However, the vehicle is programmed to do this and does it consistently! The only workaround to prevent the 12v from being drained by the vehicle while running is the workarounds in the post. (headlights, park lights, fan at 6 or 7, or trailer light wired in)

Think of it like a gasoline engine with an alternator. The alternator runs the truck while the vehicle is running. In the process it charges the battery to 100% (provided you are driving it enough). The battery only get's drained starting it, or if you use the accessories without the vehicle running. (The vehicle has accessories that run while car is off too.

If an SLA or AGM battery isn't topped off to 100% you actually kill the life of the battery, you can do a simple google search and read up on 12v batteries for vehicles and see this is true. (Totally different mindset on Lithium batteries but I will let you research that yourself too).

We can't speculate on Escapes unless someone has an Escape Hybrid and would like to verify the same testing as we have been doing here.

Yes it has been consistent with some vehicles you are correct, but it's a programming issue. Ford keeps looking at parasitic draw thinking that's the case. (I am sure that is one part of the problem) However, this charging scheme is a big deal that will deplete a SLA and AGM battery prematurely and have the same affect as the parasitic draw.

My truck had the ABS and ACCM module updated back in May of 2025 (I bought it April 2025, and it was built Jan of 2025). It has an AGM battery stock from Ford, my parisitic draw is very minimal at 12-18mA but my truck is still programmed to drain the battery at 92% and not let it charge any further. My truck is typically between 80% - 90% due to all the driving I do, but this will prematurely kill the battery.

The 2025 update is NOT the same as the one just released. And if YOUR battery is being drained as it's being driven, that's a different problem unique to your vehicle. There has not been one battery that is being drained that I've seen. If that was the case, the problem would be MUCH MORE widespread because there are a lot of people who drive various ways. In every vehicle we've seen, the vehicle will go to deep sleep first and will continue draining until dead if left alone. That's a drain issue primarily. Try the most recent update. Then tell me what happens. If the dealership connects the scan tool and says that there's no update available. And your Maverick is losing charge as it is driven, you are NOT having the same problem as everyone else. Ford did buy back one of the vehicles we had because they couldn't find the drain (it was BEFORE the most recent software release. ) But Every other vehicle WE had was cured by the previous update. They even still used the flooded battery. One has the original battery. The vehicles have been here for their oil changes. So I know the problem was solved.

 

[rslilly76]

The 2025 update is NOT the same as the one just released. And if YOUR battery is being drained as it's being driven, that's a different problem unique to your vehicle. There has not been one battery that is being drained that I've seen. If that was the case, the problem would be MUCH MORE widespread because there are a lot of people who drive various ways. In every vehicle we've seen, the vehicle will go to deep sleep first and will continue draining until dead if left alone. That's a drain issue primarily. Try the most recent update. Then tell me what happens. If the dealership connects the scan tool and says that there's no update available. And your Maverick is losing charge as it is driven, you are NOT having the same problem as everyone else. Ford did buy back one of the vehicles we had because they couldn't find the drain (it was BEFORE the most recent software release. ) But Every other vehicle WE had was cured by the previous update. They even still used the flooded battery. One has the original battery. The vehicles have been here for their oil changes. So I know the problem was solved.

Cry all you want, but my data matches @Mavster Mechanic testing as well, and I have included screenshots. The vehicle stops charging at 92% and starts charging if you do one of 4 things to get it to trigger it to charge. (go look at the readings and I am not the only one that has verified this)

My vehicle has all the ACCM and ABS updates so don't tell me that Ford has fixed anything.
Yes the parasitic draw is minimal on my truck which is 12-18mA (IDK what it was before the updates.)

I for the record have not had any deep sleep issues with my truck in the 13 months I have owned it. But I did prove that the truck actually drains the battery while the vehicle is on if the battery is above 92% SOC. That is not debatable, you can look at the data.

If the truck doesn't consistently charge the 12v battery to 100% this will prematurely degrade the battery. There is no denying this! Patristic draw will drain it sure, but the battery will fail prematurely from not being charged correctly as well. I do believe this is two things happening and Ford hasn't addressed this yet.

 

[Darryl]

The 2025 update is NOT the same as the one just released. And if YOUR battery is being drained as it's being driven, that's a different problem unique to your vehicle. There has not been one battery that is being drained that I've seen. If that was the case, the problem would be MUCH MORE widespread because there are a lot of people who drive various ways. In every vehicle we've seen, the vehicle will go to deep sleep first and will continue draining until dead if left alone. That's a drain issue primarily. Try the most recent update. Then tell me what happens. If the dealership connects the scan tool and says that there's no update available. And your Maverick is losing charge as it is driven, you are NOT having the same problem as everyone else. Ford did buy back one of the vehicles we had because they couldn't find the drain (it was BEFORE the most recent software release. ) But Every other vehicle WE had was cured by the previous update. They even still used the flooded battery. One has the original battery. The vehicles have been here for their oil changes. So I know the problem was solved.

Here's the problem with that statement. The 12v battery is actually being drained while the vehicle is running. SLA starts draining at 85% and AGM starts draining at 92%. In no way shape or form should this ever happen unless the DC/DC converter fails and the truck needs to run on 12v battery alone. However, the vehicle is programmed to do this and does it consistently! The only workaround to prevent the 12v from being drained by the vehicle while running is the workarounds in the post. (headlights, park lights, fan at 6 or 7, or trailer light wired in)

Think of it like a gasoline engine with an alternator. The alternator runs the truck while the vehicle is running. In the process it charges the battery to 100% (provided you are driving it enough). The battery only get's drained starting it, or if you use the accessories without the vehicle running. (The vehicle has accessories that run while car is off too.

If an SLA or AGM battery isn't topped off to 100% you actually kill the life of the battery, you can do a simple google search and read up on 12v batteries for vehicles and see this is true. (Totally different mindset on Lithium batteries but I will let you research that yourself too).

We can't speculate on Escapes unless someone has an Escape Hybrid and would like to verify the same testing as we have been doing here.

Yes it has been consistent with some vehicles you are correct, but it's a programming issue. Ford keeps looking at parasitic draw thinking that's the case. (I am sure that is one part of the problem) However, this charging scheme is a big deal that will deplete a SLA and AGM battery prematurely and have the same affect as the parasitic draw.

My truck had the ABS and ACCM module updated back in May of 2025 (I bought it April 2025, and it was built Jan of 2025). It has an AGM battery stock from Ford, my parisitic draw is very minimal at 12-18mA but my truck is still programmed to drain the battery at 92% and not let it charge any further. My truck is typically between 80% - 90% due to all the driving I do, but this will prematurely kill the battery.

There's no need to speculate. The escape and Maverick have the same powertrain. But the escape is made in the USA. The Maverick in Mexico. Modules may possibly be sourced from different suppliers. But the escape that was made until they were discontinued came out in 2020. By the way the 2025s and 2026s don't generally have that problem. This makes me think there's an internal difference in one or more modules even though the parts are interchangeable. And Ford was likely trying to figure out a software fix rather than a much more expensive hardware replacement

 

[rslilly76]

There's no need to speculate. The escape and Maverick have the same powertrain. But the escape is made in the USA. The Maverick in Mexico. Modules may possibly be sourced from different suppliers. But the escape that was made until they were discontinued came out in 2020. By the way the 2025s and 2026s don't generally have that problem. This makes me think there's an internal difference in one or more modules even though the parts are interchangeable. And Ford was likely trying to figure out a software fix rather than a much more expensive hardware replacement

Make all the excuses you want, @Mavster Mechanic has found an issue, and others have confirmed the issue. Doesn't matter who built what, or where the parts came from. The issue is the truck stops charging and actually starts draining the 12v battery 85% for SLA and 92% for AGM. PROVEN!

 

[Mavster Mechanic]

The battery level has been sufficient for hybrids and conventional vehicles since they started using a battery life monitor. It's only been a consistent problem in some of THESE vehicles. So the charge level evidently isn't the problem. The Maverick is the problem given the fact that the problem is largely absent in the very similar Escape hybrid . I suspect it's a hardware issue that Ford is trying to program around because the escape and Maverick likely use similar components but possibly minor differences in some internal components

Darryl:

My 2022 Hybrid never had a resting voltage higher than 12.3 volts from factory new.

As you know; it takes very little juice to start a hybrid, so this "got by" or was "barely sufficient" for 3 years. But there was no reserve. I got by because I drove 6 days a week.

My 12 v quickly "setttled in" at 60% SOC and stayed there. For 3 years.

The truck did not attempt to charge it higher. When I bench charged it to 100% within a few days the truck intentionally drained it down to 60% again.

Can you tell me the reason for this?

I pulled fuse 11. Never used any connected services or remote starts, etc.
I put a data logger in mine after.
No parasitic draw.

Now, with a brand new battery, the truck is intentionally draining it down in to 80% range. While driving.

Why is it doing this?
I had all recalls done that were available as of Summer 2025. Has not been to a dealer since.

 

[rslilly76]

So another crazy thing battery was at 99% when I parked it, went to leave at noon battery is magically at 92% and went strait to drain mode when started. my sleep draw was 30mA too which has normally been at 12-18mA

I'm gonna set the parking brake tonight for fun to see what happens

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