HYBRID 12V Battery Mystery SOLVED

[Dad]

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...

Color me "amazed". I have a voltage indicator on my truck (not as sophisticated as yours), but did a quick experiment with turning on my headlights and sure enough, voltage reading went from 12.x to 14.x

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[Glen Baker LLC]

Color me "amazed". I have a voltage indicator on my truck (not as sophisticated as yours), but did a quick experiment with turning on my headlights and sure enough, voltage reading went from 12.x to 14.x

I had the same exact experience last night coming home from a hike.
Now the quandary is.
Why do switched on or automatically turned on because it's dark out headlights boost. The voltage, but yet DRL's do not.
The Mavericks DRL's are not dimmed whatsoever compared to full-on headlights. NO I'm not referring to your Hi beams.

And of course the parasitic draw.

 

[Dad]

I had the same exact experience last night coming home from a hike.
Now the quandary is.
Why do switched on or automatically turned on because it's dark out headlights boost. The voltage, but yet DRL's do not.
The Mavericks DRL's are not dimmed whatsoever compared to full-on headlights. NO I'm not referring to your Hi beams.

And of course the parasitic draw.

Lariat hybrid uses different DRLs than your XLT and it looks to me they are less bright than headlights. Hard to say, because I know what my Lariat looks like, but I have no experience with the XLT except in photos and what I see on the road occasionally. I would think one's headlamps draw more current.

 

[Tall Hobbit]

Good day, @Tall Hobbit

Just a thought on using the "jellyfish launcher" to add electrical load on the system for any extended time.

I have read here on the MTC about some who have used their high box lights (situated with the 3rd brake light) for extended periods and reported that the halogen bulbs that come from the factory have melted the lens cover!

This is one of the reasons I changed mine out for LED bulbs...more light and more safety.

Again, just a thought on my part!

Have a great day,

Andy

Appreciate the thought Andy. Just with normal use where they stay on a few seconds after lock/unlock, door opening... already the cheap plated plastic reflectors are melting like some have reported -you mean the actual outer clear plastic cover is melting when people intentionally have them switched on for an extended period?

I don't have any hitch receiver (major regret) or trailer wiring exposed to do a light, but I do have USB and power points on the pigtails in the bed thanks to @Maverick_Innovation_Designs. Maybe there's a product I could plug in that would draw enough to trigger the charging without putting extra wear on headlights or high box lights.

 

[MakinDoForNow]

Appreciate the thought Andy. Just with normal use where they stay on a few seconds after lock/unlock, door opening... already the cheap plated plastic reflectors are melting like some have reported -you mean the actual outer clear plastic cover is melting when people intentionally have them switched on for an extended period?

I don't have any hitch receiver (major regret) or trailer wiring exposed to do a light, but I do have USB and power points on the pigtails in the bed thanks to @Maverick_Innovation_Designs. Maybe there's a product I could plug in that would draw enough to trigger the charging without putting extra wear on headlights or high box lights.

2022 lariat hybrid ambient temp 84. 12v was on noco g5 . This am drive 60 miles then after 3 hours drove 25 miles off 20 mins drove 6 miles, off 30 mins then drove 28 miles. Off for 1 hour 10 mins. Then drove cig monitor showed 14.7 v did not change with head lights on, or off Or with high beams on. Then additionally with MAX AC on or off. CIG MONITOR Stayed 14.7 v !!!

 

[SafetyGuy]

Appreciate the thought Andy. Just with normal use where they stay on a few seconds after lock/unlock, door opening... already the cheap plated plastic reflectors are melting like some have reported -you mean the actual outer clear plastic cover is melting when people intentionally have them switched on for an extended period?

I don't have any hitch receiver (major regret) or trailer wiring exposed to do a light, but I do have USB and power points on the pigtails in the bed thanks to @Maverick_Innovation_Designs. Maybe there's a product I could plug in that would draw enough to trigger the charging without putting extra wear on headlights or high box lights.

I also have the @Maverick_Innovation_Designs installed on the back of my truck...absolutely wonderful construction and very happy with them.

They do now have a new design out that allows higher draw for higher power demands...if I didn't already have mine, I would definitely get the new ones!

They allow a higher draw, is what I am thinking and that might work in your favour.

However, you can plug in a a 12 volt cooler (one of my plugs at the back is a 12 volt power port/lighter socket for this exact purpose) into yours if that is what you have, as that is a good amount of draw from the power port!

Maybe it will work for you. Just a thought that works with what you suggested.

Have a good one,

Andy

 

[Mavster Mechanic]

Some people (more than one) missed that by using the trailer wire:

IT DOES NOT MATTER how many watts you draw off it.

It (computer) only needs to DETECT something is there.

 

[Mavster Mechanic]

After 10 hours parked, just after key on with hitch LED lamp attached:

96% and 22 amps at 14.4 volts

97% and 6 amps at 14.4 volts

99% and 3 amps at 14.4 volts

100% and 1 amp at 14.2 volts

Soon zero amps in or out. Just stasis.
How is this not perfect?

Series of photos taken in 25 minutes.

 

[HeyBales]

I charged using under hood jump posts with battery connected. Theoretically the oem bms will count all insy's and outsy's. There could be a degree or so difference in ambient temp where the noco is located and the battery. I think the preferred noco location is touching side of battery. (Not gonna happen).

See my post before with several pictures.
There is NO tracking of external charging.
Only with the key to On position, or pushbutton the same.

And that would be a bad thing actually, to count that in the math.
The BMS will see the end result of doing it - higher Voltage, after a rest period to be a valid voltage reading.

Also - you commented on having the AC on auto - but the point was Fan speed being at 6, not the AC.
AC is run off the HV system, not 12V system.
Was fan speed that high on auto?

Probably doesn't matter, the fact your 12VB is higher voltage already - means not a fully charged battery.
If it was around 12.8V that means the BMS isn't trying to charge.

 

[Mavster Mechanic]

Tonight I put a 30 watt, 40 watt, and 60 watt load on the built-in 120 VAC inverter.

Had zero effect on the 12 v system.

Switching the 60 watt on and off I could clearly see a "wiggle" in the 220 v Hybrid battery. Clearly the HV battery was feeding the inverter. 12v battery didn't know the inverter load was there. And the computer did not alter the 12.8v coming from the DC/DC converter.

 

[HeyBales]

I got no inverter module either.

I'd also be curious with 22MY compared 24MY - the BdyCM.
The strategy level. Not sure if that is scanner speak, otherwise known as software version, or if that is a different thing, and I can't read it.

BdyCM - Body Control Module
Bus: HSCAN
Part number: MU5T-14B476-FCU
Calibration level: MU5T-14B476-FCU
Strategy : MU5T-14C184-ACR

Must not have had an upgrade in any recalls - info from very early with another scanner read showed the same.

 

[samspritzer]

Color me "amazed". I have a voltage indicator on my truck (not as sophisticated as yours), but did a quick experiment with turning on my headlights and sure enough, voltage reading went from 12.x to 14.x

After reading through 7 pages of fascinating commentary that rivals the still yet unresolved mystery of UFOs, this one post tickled my fancy....

I am as old as Glen Baker so he might be able to relate a thing or two. Recalling back in the day (as in last century) when we had analog gauges, I remember every time I turned on the headlights, the BATT one would jump a bit before settling back into where it started from. And sometimes, it would jump and stay there. Sometimes the idiot light would come on, other times not.

Since we didn't have "compooters" back then, the only thing that would do this is the voltage regulator in the alternator. This would be a simple transistor that kind of act like an on/off switch to prevent overcharging of the battery.

While possible and perhaps someone more knowledgeable than the average DIYer, could something in the alternator be factored into the nuances of this discussion? What would happen one took the alternator out of the equation? Call me curious, but as a former forensic accountant, we always relied on addition by subtraction to narrow down the clues to the end result.

 

[MakinDoForNow]

See my post before with several pictures.
There is NO tracking of external charging.
Only with the key to On position, or pushbutton the same.

And that would be a bad thing actually, to count that in the math.
The BMS will see the end result of doing it - higher Voltage, after a rest period to be a valid voltage reading.

Also - you commented on having the AC on auto - but the point was Fan speed being at 6, not the AC.
AC is run off the HV system, not 12V system.
Was fan speed that high on auto?

Probably doesn't matter, the fact your 12VB is higher voltage already - means not a fully charged battery.
If it was around 12.8V that means the BMS isn't trying to charge.

On Max Auto Fan speed is at max also (6).
True or not, I have no proof of external charging being tracked but from what I have read the BMS is located on the negative battery post with requirement charger (nothing else either) is not attached to battery post but to other body ground so that the BMS can see the activity. I agree that when I was driving with cig monitor showing 14.7 that significant charging may not have been occuring based on leaving cig monitor active after 12 minute drive and 20 minute rest my reentry shoes battery at 12.4 volts while after opening door, closing, prior to touching push button (it appears that just opening door causes about 0.2v reduction due to truck waking up so I believe battery should actually be closer to 12.6v, need memory on cig monitor to verify, of course). This battery is 15 month old Ford max series bxt99rt4. I will install monitor with memory onto battery with body ground that I can read with phone app. It will need it separate key on charging bat, of course .

 

[Busa789]

While possible and perhaps someone more knowledgeable than the average DIYer, could something in the alternator be factored into the nuances of this discussion? What would happen one took the alternator out of the equation? Call me curious, but as a former forensic accountant, we always relied on addition by subtraction to narrow down the clues to the end result.

I believe the hybrid does not have a traditional alternator, but gets its power from the high voltage system.

 

[Mavster Mechanic]

After reading through 7 pages of fascinating commentary that rivals the still yet unresolved mystery of UFOs, this one post tickled my fancy....

I am as old as Glen Baker so he might be able to relate a thing or two. Recalling back in the day (as in last century) when we had analog gauges, I remember every time I turned on the headlights, the BATT one would jump a bit before settling back into where it started from. And sometimes, it would jump and stay there. Sometimes the idiot light would come on, other times not.

Since we didn't have "compooters" back then, the only thing that would do this is the voltage regulator in the alternator. This would be a simple transistor that kind of act like an on/off switch to prevent overcharging of the battery.

While possible and perhaps someone more knowledgeable than the average DIYer, could something in the alternator be factored into the nuances of this discussion? What would happen one took the alternator out of the equation? Call me curious, but as a former forensic accountant, we always relied on addition by subtraction to narrow down the clues to the end result.

The EcoBoost engine is like you remember.

The hybrid one is completely different and nothing like you remember.

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