HYBRID 12V Battery Mystery SOLVED

[HeyBales]

Thanks; I grasp this better and says about what I guessed. Mornings are 11.9-12.1 now @ cold crank. XL doesn't have push-button start. So it seems the main thing I can to for 12v battery life is combine frequently whipping the horses on long journeys in this economy truck, simultaneously using The Tricks. I'm not likely to do the former often enough to satisfy anyone, which makes the latter pointless. Hopefully Ford will be buying me 12v replacements until they eventually reprogram the DC/DC recharging.

This is becoming just another version of the 'you're not driving it enough' excuse that gets customers to go away.

Yep, no benefit to ya now. We are both going for a new battery before warranty is up. Next 5/1/27 for me. Currently 11.8V mornings, with 42-49% SOC stated. They don't make it consistent.

Hopefully the dealers don't find out about The Tricks.
Then they'd be telling people they need to drive more at night so their lights are on, or fans on high. I'm sure they'd love to tell people without hitches - they need install one.

Don't hold your breath on reprogramming the logic. I'm betting they are pulling a failsafe for the battery being in the cabin, and unknown what size battery may have been installed by a driver, that is way smaller than spec. I know you can get smaller for cheaper - but then it could be easier to overcharge if unknown.

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[KJHChemist]

It's been interesting reading through this thread, as I'm having the same issue with my gas-powered Maverick and my brand new AGM battery is reading a resting voltage of 12.1 -ish. They supposedly did a BMS reset when they installed, but I'm going to do the high beam/brake reset this evening and then lock it up overnight. I already tried the Forscan SOC adjustment and that did nothing. A long drive will charge it up, but then it returns to the 12.1-ish.

 

[SafetyGuy]

It's been interesting reading through this thread, as I'm having the same issue with my gas-powered Maverick and my brand new AGM battery is reading a resting voltage of 12.1 -ish. They supposedly did a BMS reset when they installed, but I'm going to do the high beam/brake reset this evening and then lock it up overnight. I already tried the Forscan SOC adjustment and that did nothing. A long drive will charge it up, but then it returns to the 12.1-ish.

Good day

I will just quickly jump in here to say driving alone may not charge the battery sufficiently before doing the relearn!

I would suggest getting a smart charger capable of at least 4-5 amps and must be AGM appropriate.

Hook it up and charge the dickens out of the battery so that the battery has the best charge possible! A quick surface charge is insufficient. Fully charged only.

Then carry out the relearn process. This is perfect timing to do it correctly, as you said it is a new battery so should not be sulphated or damaged yet by undercharging (I hope anyways).

Okay, done...good luck and let us know how it goes.

Andy

 

[KenE]

Good day

I will just quickly jump in here to say driving alone may not charge the battery sufficiently before doing the relearn!

I would suggest getting a smart charger capable of at least 4-5 amps and must be AGM appropriate.

Hook it up and charge the dickens out of the battery so that the battery has the best charge possible! A quick surface charge is insufficient. Fully charged only.

Then carry out the relearn process. This is perfect timing to do it correctly, as you said it is a new battery so should not be sulphated or damaged yet by undercharging (I hope anyways).

Okay, done...good luck and let us know how it goes.

Andy

Perfectly stated Andy. I did this exact thing on my "ailing" 2025 AGM battery, using NOCO 5A charger, immediately followed up with overnight relearn. Now charges to 99% using lights to force full charge.

 

[SafetyGuy]

Perfectly stated Andy. I did this exact thing on my "ailing" 2025 AGM battery, using NOCO 5A charger, immediately followed up with overnight relearn. Now charges to 99% using lights to force full charge.

Wonderful, Ken!

I am glad you were helped out following Mavster Mechanics discovery of the turning headlights on trick, and the other things that have been learned here on MTC.

And of course it is best to charge the battery completely...no use doing a whole relearn process with a partially charged battery...for sure the truck will only charge to the low state the battery was at at the RELEARN etc process.

A bit of positive affirmation as to how you were helped can help the OP know others have followed the steps and were helped.

Others need to keep in mind if their battery has been already compromised/damaged for a long period of time being chronically undercharged and the battery is on its last legs....there may be no saving it and purchasing a new battery, fully charging it before installation (NOT A QUICK SURFACE CHARGE, THAT IS A JUNK CHARGE just to get you started and out the door), and then doing the manuals process for a new battery install is needed.

Having a multi-meter and getting familiar with reading your battery voltage to help determine its health is a worthwhile endeavour, more need the experience southern can help themselves more easily.

Have a great day,

Andy

 

[Mavster Mechanic]

It's been interesting reading through this thread, as I'm having the same issue with my gas-powered Maverick and my brand new AGM battery is reading a resting voltage of 12.1 -ish. They supposedly did a BMS reset when they installed, but I'm going to do the high beam/brake reset this evening and then lock it up overnight. I already tried the Forscan SOC adjustment and that did nothing. A long drive will charge it up, but then it returns to the 12.1-ish.

As other said DON'T.

Let me clarify based upon my experience with a 2022 hybrid.

The lights flash brake tap thing tells this computer "This is your 100% baseline."

If it is really 50% at the time you do the reset; the truck will consider 50%
the new normal.

MUST do the reset AFTER a full charge.
That's my understanding of it.

 

[KJHChemist]

Good to know. I’ll put the charger on it tomorrow and get it charged up, then do the overnight reset and start running with my lights on. I want it to get a full charge because it’s about to sit for roughly 14 days during a trip.

 

[MakinDoForNow]

Good to know. I’ll put the charger on it tomorrow and get it charged up, then do the overnight reset and start running with my lights on. I want it to get a full charge because it’s about to sit for roughly 14 days during a trip.

If it's going to sit 14 days where you can leave charger on it just leave it on. From time to time I will leave my noco g5 on my mavericks. Or if it's located where it's safe to run set max idle time to an hour or(?) and remote start with app at 7-10 days.

 

[KenE]

As other said DON'T.

Let me clarify based upon my experience with a 2022 hybrid.

The lights flash brake tap thing tells this computer "This is your 100% baseline."

If it is really 50% at the time you do the reset; the truck will consider 50%
the new normal.

MUST do the reset AFTER a full charge.
That's my understanding of it.

If it's going to sit 14 days where you can leave charger on it just leave it on. From time to time I will leave my noco g5 on my mavericks. Or if it's located where it's safe to run set max idle time to an hour or(?) and remote start with app at 7-10 days.

Long term storage using a smart charger is best option if you have that option. That's what I do now with all our other vehicles, tractor, lawn tractor batteries when we head to south Texas for winter. We drive our Mav so it gets driven most days. Never thought about the idle time w/remote start. Good tip.

 

[MakinDoForNow]

Long term storage using a smart charger is best option if you have that option. That's what I do now with all our other vehicles, tractor, lawn tractor batteries when we head to south Texas for winter. We drive our Mav so it gets driven most days. Never thought about the idle time w/remote start. Good tip.

Remember remote start can only be done TWICE with total remote time out to max idle time WITHOUT shifting into drive to reset the two count and max idle limits......

 

[Mavster Mechanic]

Just had the trailer module reprogram done.

NO CHANGE IN BEHAVIOR.

They handed it back to me at 94% SOC showing.

It showed 12.8 to 12.7 and discharging on the 20 minute drive home. Last 2 minutes I turned on parking lamps and immediately it went to 14.5 volts and charging.

"Free inspection" stated brake pads were 8mm all around.

I had just used digital calipers days ago that showed 9mm on fronts and 7mm on rears. "Close enough?"

Free inspection said tire tread was 8mm all around. Weird. The exact same tires almost exactly 1 year ago to the day, and 23,000 miles younger were 8mm all around. "Close enough?"

Me thinks they pencil whipped the form
Since they knew I wasn't spending any money there today.

 

[KJHChemist]

It’s going to be parked in a public parking garage, so using a battery tender not a likely option. I’ll make sure AC and auto lights are off when I park it and do the remote start thing. I also have a jumper box that’s charged up and going with me.

I tried running with lights on yesterday and about 2 hours after I parked my voltage was reading about 12.3. This morning it was back down to 12.15.

 

[MakinDoForNow]

It’s going to be parked in a public parking garage, so using a battery tender not a likely option. I’ll make sure AC and auto lights are off when I park it and do the remote start thing. I also have a jumper box that’s charged up and going with me.

I tried running with lights on yesterday and about 2 hours after I parked my voltage was reading about 12.3. This morning it was back down to 12.15.

Was 12.15 taken with hood left up overnight? If you opened drivers door, unlatched hood then took reading the battery will have some draws active. The draw will likely be more in the hybrid than the Ecoboost. In my hybrid the voltage readings between the hood left open to access the jump pins can be 0.2v-0.3v higher than if the door and hood are opened before the readings are taken.

 

[Mavster Mechanic]

It’s going to be parked in a public parking garage, so using a battery tender not a likely option. I’ll make sure AC and auto lights are off when I park it and do the remote start thing. I also have a jumper box that’s charged up and going with me.

I tried running with lights on yesterday and about 2 hours after I parked my voltage was reading about 12.3. This morning it was back down to 12.15.

I think the lights on trick is a Hybrid thing.

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