HYBRID 12V Battery Mystery SOLVED

[MakinDoForNow]

So far, running headlamps (or trailer lamps) 10 days in a row mine has never gone above 14.8 volts which should be safe for any battery.

In the past with a deeply discharged battery (lower than 60%) I did see 15.3 and 15.4 volts. But never in the past 10 days.

I have 22 lariat hybrid. If ambient temp is below 60°F I will see 15+ volts.

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[Mavster Mechanic]

Now we will be buying new headlights once a year instead of batteries.

Not once a year. But maybe more often.

Which is why this $10 attachment is so attractive... If I forget I ever had blind spot warning... like the good old days.

In a 2025 or 2026 this $10 hitch brake light should not deactivate your safety enhancement if you set the trailer settings correctly. IE Put in the shortest trailer length allowed. Some Full Size Ford Trucks allow a trailer to be set to zero feet for exactly this purpose: using trailer wire for something other than a trailer.

 

[Mavster Mechanic]

I have 22 lariat hybrid. If ambient temp is below 60°F I will see 15+ volts.

With a 100% charge battery or a partially charged battery?

 

[HeyBales]

Oh - mine's different then, right now.
I'm always at 14.x - 15.x.
No matter initial seconds of 15 A down to float 0.5 A.

But that's probably because my battery is currently no where near 12.8V resting.
When it was, I did see that effect of draw.
Oh those carefree days! Literally - only lasted a few days...

I'll see what happens on drive home tonight - plan on letting the initial high amp drop to float level - then I'll test with fan and headlights.
And video it.

Glenn - aren't you coming up on the season that testing a 12V resistance heater would work well.

Well - it appears for a battery not already up high enough, or some other reason - the effect doesn't work for me.
I have NO Trailer Control Module, as I don't have a tow package, if that is a difference.
2024 XLT, no option package for 120V and inverter, if that is a difference.

I'll reply back when video is on youtube to view (can't pause video and then suspend screen, stops video - arg).

Start of drive - 58% SOC, 11.9 V (day before was 65% SOC after 4 hr drive)
I noticed I must have had a drain event prior night, charge 32 Ah, discharge 34 Ah, even with some rounding errors - usually closer than that - that causes willingness to do high charging Amps.

20 min drive home, higher than normal float charge 1.34A at this point - 63% SOC.
Fan speed 6, no headlights, no brake pedal with those lights (which is 8-9A draw too).
Note DCDC Converter Low Current - 16A, or 17A actually.

Fan @ 7 really Amps it up - 25A. Normal battery current fluctuations up/down.

Back to fan speed 1. No improvement to battery current during that test.

Headlights on.

Now - if you want to call 0.1 or 0.2A extra on battery current an improvement - it'll take me awhile to see that. But that's the normal fluctuation on it's way down.

Either the BMS isn't fooled with this method, and due to some known high internal resistance figures it knows it shouldn't be charged at high Amp for very long - or I'm missing a component on my truck.

Hopeful that someone with scanner can test that may have option for inverter but not towing package, or vise-versa. Or was there an option package for inverter but no tow?

No - I'm not going to charge my battery and see if that makes a difference.
Did that on OEM battery when it seemed it was already a problem 4 months after getting truck - there was no SOC% above 90 after reset and relearn.
And I don't want this battery to last past warranty - looking to that AGM.

 

[HeyBales]

I'm an old guy who seldom drives at night, doesn't even have a trailer hitch, and doesn't like having the vent on high and over 3 years I've never had any battery problem with my '22 xl hybrid.

And Michigan!
Pretty sure you enjoy some cold months.
Examples like yours is why I think mine has a bad battery sensor.

 

[MakinDoForNow]

With a 100% charge battery or a partially charged battery?

Never actually checked battery. But is true even when truck is readied after noco g5 has been on for 7+ days and showing solid gree with no other lights (standby).

 

[Glen Baker LLC]

Not once a year. But maybe more often.

Which is why this $10 attachment is so attractive... If I forget I ever had blind spot warning... like the good old days.

In a 2025 or 2026 this $10 hitch brake light should not deactivate your safety enhancement if you set the trailer settings correctly. IE Put in the shortest trailer length allowed. Some Full Size Ford Trucks allow a trailer to be set to zero feet for exactly this purpose: using trailer wire for something other than a trailer.

David,
Thank You for posting that.
I knew there was a difference in later years and in the way that the trailer hitch brake light worked in relation to the BLIS blind lane information system. I was not certain of how or years.
That's why I was asking a @okgaz
specifically what year his Maverick was.
Again thank you very much for your time and work on this forum.

 

[HeyBales]

You do know if look in Forscan settings max charge is around 80% .
There are people changing that to 100% fixing the notification issues low battery.

It's been proven multiple times by those with scanners.
80% is NOT max charge.
It keeps charging above that.
Float charge, below 1A.
Or in the thread you are in, picture proof with no change.

And it's been shown by those that changed the setting - did NOT get charge levels such they suddenly got around 90 or 95% SOC.

I've also seen many posters that changed the setting along with 2 other changes - like a new battery. Impossible to isolate 1 change being the reason when you do 3 things.
Yes - no more Deep Sleep Mode alerts.

 

[Mavster Mechanic]

Never actually checked battery. But is true even when truck is readied after noco g5 has been on for 7+ days and showing solid gree with no other lights (standby).

Ok. Coming right off a Noco charger I'd consider that 100%.

But... a variable... did you charge it attached or with at least one battery cable detached from your truck?

At least in mine, detaching one battery cable forces a battery SOC reset. If you left your battery fully connected to the truck, even though the battery was 100% maybe the truck didn't know that it was?

 

[Mavster Mechanic]

All this fancy smanchy tech and 3 years of discussions!

Holy Cow!

How did batteries survive 5, 6, 7 years in the past with just an alternator and voltage regulator?

 

[Builder]

Some of you will laugh.
Some of you will cry.
Some of you will say "Holy Crap that's amazing!"
Some of you will say "Holy Crap that's dumb."

Here goes.

Fact: 2022 Hybrid (and others) actively drain a 12 volt battery to the computed 80% charge level.
Then do not try to add charge to the 12 volt battery until a computed 60% or lower charge is reached. God only knows why.
For 3.5 years my 12v battery has been "maintained" at about 60% charged. Always a resting voltage of 12.1 or 12.2.

Fact: running your headlamps will force the 12v battery to be 100% charged given enough time. (DRL will not do it. Parking Lamps only will do it.)

Fact: running your vents blower at speed 6 or 7 will force the 12v battery to be charged to 100% given enough time.

Fact: attaching a trailer, 4-pin or 7-pin will force charge the 12v battery to 100%.

Theory A: the truck needed to detect 12 volt demand, and above a certain wattage to trigger 12 volt charging.

Why would fan level 6 trigger battery recharging and fan level 5 would not? Why would full headlamps trigger battery recharging, but DRL would not?
Did the truck detect demand to run my camper fridge and coach battery?

I tested this last part. From Amazon I ordered a $10 LED brake light for the 2" hitch receiver with 4-pin connector.
Wow! The LED brake light pulling no power when not braking, and only 4 or 5 watts when braking DOES TRIGGER 12 volt battery recharging to 100%.
It's not the electrical demand that triggers recharging. It is simply thinking a trailer is there that triggers recharging.

Theory A shot down.

But this explains a lot.
This explains why some people have more 12v battery issues than others.

Those that drive at night a lot have more battery charging by happenstance.

Those that use fan speed 6 or 7 have more battery charging by happenstance.

Those who connect trailer wiring (and you don't even need a trailer!) have more battery charging.

Not a permanent fix. But a work around. Some of you may prefer running your headlamps more often over plugging into a home charger.

My 12v battery has been 100% for ten days in a row now. And is maintained at 12.7 or 12.8 volts. But I need to do one of the three "triggers" above or it rapidly starts to decline.

More to come...

Great investigation on the unsolved 12v battery issue. I tried the parking lamp option for a more aggressive charge on my AGM. I constantly monitor the amp inflow to the 12v to determine the recharge level. Unfortunately, turning on the parking and/or headlamps made no difference in the recharge amp levels for my 12v AGM regardless of drive time. Oh well …….

 

[HeyBales]

Ok. Coming right off a Noco charger I'd consider that 100%.

But... a variable... did you charge it attached or with at least one battery cable detached from your truck?

At least in mine, detaching one battery cable forces a battery SOC reset. If you left your battery fully connected to the truck, even though the battery was 100% maybe the truck didn't know that it was?

That would be the 9 hr locked Relearn process to discover that.
Disconnected for the charge up may have forced it that night when reconnected.
Which would still be a good reason for doing it that way.
Otherwise the normal schedule for the Relearn could be 1-2 days away.

 

[Vydeoguy]

Some of you will laugh.
Some of you will cry.
Some of you will say "Holy Crap that's amazing!"
Some of you will say "Holy Crap that's dumb."

Here goes.

Fact: 2022 Hybrid (and others) actively drain a 12 volt battery to the computed 80% charge level.
Then do not try to add charge to the 12 volt battery until a computed 60% or lower charge is reached. God only knows why.
For 3.5 years my 12v battery has been "maintained" at about 60% charged. Always a resting voltage of 12.1 or 12.2.

Fact: running your headlamps will force the 12v battery to be 100% charged given enough time. (DRL will not do it. Parking Lamps only will do it.)

Fact: running your vents blower at speed 6 or 7 will force the 12v battery to be charged to 100% given enough time.

Fact: attaching a trailer, 4-pin or 7-pin will force charge the 12v battery to 100%.

Theory A: the truck needed to detect 12 volt demand, and above a certain wattage to trigger 12 volt charging.

Why would fan level 6 trigger battery recharging and fan level 5 would not? Why would full headlamps trigger battery recharging, but DRL would not?
Did the truck detect demand to run my camper fridge and coach battery?

I tested this last part. From Amazon I ordered a $10 LED brake light for the 2" hitch receiver with 4-pin connector.
Wow! The LED brake light pulling no power when not braking, and only 4 or 5 watts when braking DOES TRIGGER 12 volt battery recharging to 100%.
It's not the electrical demand that triggers recharging. It is simply thinking a trailer is there that triggers recharging.

Theory A shot down.

But this explains a lot.
This explains why some people have more 12v battery issues than others.

Those that drive at night a lot have more battery charging by happenstance.

Those that use fan speed 6 or 7 have more battery charging by happenstance.

Those who connect trailer wiring (and you don't even need a trailer!) have more battery charging.

Not a permanent fix. But a work around. Some of you may prefer running your headlamps more often over plugging into a home charger.

My 12v battery has been 100% for ten days in a row now. And is maintained at 12.7 or 12.8 volts. But I need to do one of the three "triggers" above or it rapidly starts to decline.

More to come...

 

[Vydeoguy]

Like mine that’s why! Thanks

 

[Mavster Mechanic]

Great investigation on the unsolved 12v battery issue. I tried the parking lamp option for a more aggressive charge on my AGM. I constantly monitor the amp inflow to the 12v to determine the recharge level. Unfortunately, turning on the parking and/or headlamps made no difference in the recharge amp levels for my 12v AGM regardless of drive time. Oh well …….

Volts. Did you look at voltage?

That is what happens in mine.
Headlamps off: 12.8 and slowly falling as I drive.

Headlamps on: 14.3 to 14.8 and trickle charging.

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