HYBRID 12V Battery Mystery SOLVED

[Red Eyes - Wide Shut]

David, can you clarify if "Parking Lamps only" will cause your battery to charge to 100%?

Your first post reads that way but I had assumed, based on further writing in your posts, that you intended for it to read "Parking Lamps only will NOT do it"

I ask because I just noticed that my 2023 Lariat does appear to start charging when switching the lights to Parking Lamps only, at least at 87% SOC.

Mike

Turn on heated seats and plug in a cordless tool battery charger. Clap hands twice and start the truck.

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[Tall Hobbit]

You need to stop basing things on voltage.

Voltage is not telling you anything once the key / truck is "on".

Only the "off" voltage is valid from the cigar lighter port, or the OBDII port.

Anytime the truck is "on" you are reading the DC/DC converter voltage.
Which masks the health of the 12v battery while driving.

Thanks again David. I believe! But begging your patience, what is the likely significance on the rare drive where the cig monitor responds dramatically to the tricks of the lights/fan speed, as opposed to my typical drive where it reads a steady 14.x no matter what?

P.S. the AGM I currently have installed seems to be doing better than the previous one at comparable age and mileage. Based on previously, would have expected this one to be showing major symptoms and throwing codes, but so far so good. Got the cig monitor as the first AGM was failing. In its death throes, it would read as low as 9.6 and barely start after several tries. Thankfully it seems much better this go-around, same model FoMoCo AGM.

 

[Mavster Mechanic]

David, can you clarify if "Parking Lamps only" will cause your battery to charge to 100%?

Your first post reads that way but I had assumed, based on further writing in your posts, that you intended for it to read "Parking Lamps only will NOT do it"

I ask because I just noticed that my 2023 Lariat does appear to start charging when switching the lights to Parking Lamps only, at least at 87% SOC.

Mike

Parking lamps WILL make the 2022 charge. Or full headlamps. Either. Both.

 

[Mavster Mechanic]

Update. And it's strange.

After 4 weeks of successfully keeping my 12v battery 100% charged by always running one of the 3 lamps ( head, parking, and/or trailer) I shut them off.

In 3 days, In six drives, six 1 hour drives, of not charging, my battery went down to 12.0 volts while driving. Then the DC/DC convert kicked up to 14.5 or so. And 25 amps of charging went into the 12v battery.

For several minutes. Then tapered down to 2, 1, then 0 amps

Repeat.

 

[HeyBales]

Sounds like it was pretty inspired there. Briefly.
Sounds like when I've gotten a big drain with doors open, ect.
Very motivated for a few drives at extended time at 8-10 amps.

In your case after it was purposely willing to let it drop voltage.
"Oops, too far, gotta bring that back up."

Grief.

What did the resting voltage look like after those 3 days, if dropping to 12.0 while driving.

 

[samspritzer]

Update. And it's strange.

After 4 weeks of successfully keeping my 12v battery 100% charged by always running one of the 3 lamps ( head, parking, and/or trailer) I shut them off.

In 3 days, In six drives, six 1 hour drives, of not charging, my battery went down to 12.0 volts while driving. Then the DC/DC convert kicked up to 14.5 or so. And 25 amps of charging went into the 12v battery.

For several minutes. Then tapered down to 2, 1, then 0 amps

Repeat.

Unless you're a computer programmer and have access to the code, you'll never get a definitive answer. Even if you were the smartest programmer on earth, you'll also have to deal with mitigating situations that may affect the code. This is know as "what if" in layman's terms, "if-then-else" in programming logic. In any case, the answer is always going to be 0 or 1. Depending on how you program the 0 (yes or no), the 1 will always be the opposite.

And then there are all of those gremlins caused by other programs and chips. I believe there are over 3,000 chips in today's vehicles of which each one has their own logic.

Make sense?

 

[Mavster Mechanic]

Unless you're a computer programmer and have access to the code, you'll never get a definitive answer. Even if you were the smartest programmer on earth, you'll also have to deal with mitigating situations that may affect the code. This is know as "what if" in layman's terms, "if-then-else" in programming logic. In any case, the answer is always going to be 0 or 1. Depending on how you program the 0 (yes or no), the 1 will always be the opposite.

And then there are all of those gremlins caused by other programs and chips. I believe there are over 3,000 chips in today's vehicles of which each one has their own logic.

Make sense?

My own logic:

IF running Truck
RUN headlamps
THEN 12v battery stays 100% charged

 

[MakinDoForNow]

Unless you're a computer programmer and have access to the code, you'll never get a definitive answer. Even if you were the smartest programmer on earth, you'll also have to deal with mitigating situations that may affect the code. This is know as "what if" in layman's terms, "if-then-else" in programming logic. In any case, the answer is always going to be 0 or 1. Depending on how you program the 0 (yes or no), the 1 will always be the opposite.

And then there are all of those gremlins caused by other programs and chips. I believe there are over 3,000 chips in today's vehicles of which each one has their own logic.

Make sense?

Yeppers on making sense. Even smartest programmer with code access can have difficulties. During the 1970's&80's I was having to "optimize" cobol compiled code on ibm 370 mainframe to reduce run time for completion within a 4 hour window. I would scan compilation code replacing sections with my assembler code. (Some of my routines were specifically for the particular computer that was running program).

 

[samspritzer]

My own logic:

IF running Truck
RUN headlamps
THEN 12v battery stays 100% charged

If that is a proven solution, it shouldn't take an engineer or programmer much to look at the logic of that to see what the triggering code is.

 

[DS_Ohio]

My own logic:

IF running Truck
RUN headlamps
THEN 12v battery stays 100% charged
END IF

 

[Red Eyes - Wide Shut]

They just don't want to spend the time/money to get it right. Until it is a publicized issue affecting profits it won't go away.

 

[HeyBales]

Update. And it's strange.

After 4 weeks of successfully keeping my 12v battery 100% charged by always running one of the 3 lamps ( head, parking, and/or trailer) I shut them off.

In 3 days, In six drives, six 1 hour drives, of not charging, my battery went down to 12.0 volts while driving. Then the DC/DC convert kicked up to 14.5 or so. And 25 amps of charging went into the 12v battery.

For several minutes. Then tapered down to 2, 1, then 0 amps

Repeat.

Forgot to ask - did you happen notice your avg MPG readings during those 3 days?

Since one of the theories for allowing a low battery SOC is slightly improved gas mileage - you have such a handle on your daily commute perhaps it was noticeable when it stopped charging.

Wouldn't it be funny if it was attempting some sort of de-sulf process. 25-0A, repeat.

I'd think a long drive would be the time for that - never saw it on 3-4 hr drives, or 8.

 

[MakinDoForNow]

Forgot to ask - did you happen notice your avg MPG readings during those 3 days?

Since one of the theories for allowing a low battery SOC is slightly improved gas mileage - you have such a handle on your daily commute perhaps it was noticeable when it stopped charging.

Wouldn't it be funny if it was attempting some sort of de-sulf process. 25-0A, repeat.

I'd think a long drive would be the time for that - never saw it on 3-4 hr drives, or 8.

I do remember on 2-3 drives of 10+ hours changing drivers with wife without turning truck off except to fuel with about 100 miles to E, my cig power point monitor would drop to 13.9-14.1 volts. Also at least one of the times I remember it was overcast, very humid, and temp was about 70°F with no wind. Suspect also I may have placed 12v onto my noco before trip.

 

[Mavster Mechanic]

Forgot to ask - did you happen notice your avg MPG readings during those 3 days?

Since one of the theories for allowing a low battery SOC is slightly improved gas mileage - you have such a handle on your daily commute perhaps it was noticeable when it stopped charging.

Wouldn't it be funny if it was attempting some sort of de-sulf process. 25-0A, repeat.

I'd think a long drive would be the time for that - never saw it on 3-4 hr drives, or 8.

The amount of wattage needed to propel the vehicle is huge. The amount of wattage needed to recharge a 12v battery is small.

The effect on MPG is immeasurable with the tools we have. I don't believe MPG is a factor in this funky system.

 

[rslilly76]

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...

what about the current draw from an amp for an upgraded stereo system?

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