HYBRID 12V Battery Mystery SOLVED

[BAScott62]

Don't give Ford too much credit with these quirks. A cleaner approach would be to solely use the SOC to contol the charging logic.

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[HeyBales]

The reason for the 15% instead of the 10% lies in the improvements to the trans. Larger electric motors + , if I remember correctly, an additional tooth in gear set with a change in the final ratio. Programming will be adjusted when updates reference vin #'s.

I'm convinced not.
Besides, talking %, not total output. 15% of smaller or bigger motor doesn't matter. 15% of that motors potential HP.

On the initial startup drive with near full HVB - I can reach 20% power for several seconds - and that's the 123A discharge on the reading that seems to be max in those cases.
Not sure how long it actually could go, as I'm at 25 mph very quickly despite the hill, but corner is right there, so...

I can push the 15% for a long block in those cases.

25MY PID shows they have a mere 0.5 HP max extra allowed for discharge.
So that's not a motor or discharge limit difference - that's a choice in programming.
Probably figured for keeping the HVB usable longer, and in EV mode longer. But same HVB size between years.
Or perhaps they also changed how willing 25MY can go up to 70% SOC before using the motors - so you got more battery to make use of it.

But that 15-20% isn't near the limits on 24MY yet, shoot, this is while driving and merely an assist from TM, though it is the extra boost assist 53 HP! (abouts 27% on power meter if on it's own)

 

[Mavster Mechanic]

The reason for the 15% instead of the 10% lies in the improvements to the trans. Larger electric motors + , if I remember correctly, an additional tooth in gear set with a change in the final ratio. Programming will be adjusted when updates reference vin #'s.

Naw.

Changes were very minor.
And my 2022 gets high EV power (double) for a few moments on a restart with a full battery.

Mine can. It's not mechanical. It's just not programmed. Also may be wire gauge related. Would be interested to know the gauge of the battery wire used in 25's and 26's. Likely the same. But ya never know without looking.

 

[HeyBales]

Don't give Ford too much credit with these quirks. A cleaner approach would be to solely use the SOC to contol the charging logic.

There have been some later posts showing it does do exactly that.

Of course the SOC has to be calculated, as it's being charged at the time. Or discharged as the case may be.
Hence using the tried & true method of Coulomb counting Ah while running.

Actually I'll say sadly it appears ONLY that method. The system does know resting voltage after an appropriate time not charging - as it's the basis for battery save mode 12.1 V limit.
So they should include in the logic - if that resting voltage keeps going down - charge MORE!

 

[Mavster Mechanic]

Don't give Ford too much credit with these quirks. A cleaner approach would be to solely use the SOC to contol the charging logic.

Didn't cars and trucks pre digital age charge just fine with no logic at all?

 

[BAScott62]

That's the point I was trying to make. Turning on your running lights should NOT cause the battery to mysteriously charge over its settings. I'm skeptical that this was an intentional decision.

 

[MakinDoForNow]

That's the point I was trying to make. Turning on your running lights should NOT cause the battery to mysteriously charge over its settings. I'm skeptical that this was an intentional decision.

Probably not intentional but certain things could be affected by programming flow.

 

[samspritzer]

Didn't cars and trucks pre digital age charge just fine with no logic at all?

Either that or we weren't as sophisticated, back in the day. It would have been pretty boring topic.

 

[El Kabong]

Didn't cars and trucks pre digital age charge just fine with no logic at all?

I owned a used 2001 Subaru Forester XS Premium at one time, picked it up somewhere around 2009 super cheap because it had "an electrical gremlin" and the battery would die, previous owner gave up on it after replacing the alternator twice (and bought themselves a new Forester).

They had replaced the battery with a new AC Delco unit prior to replacing the alternator the first time. The AC Delco battery would take a charge from a charger and load test OK, but the Forester could not maintain it.

I replaced the battery with an Interstate unit based on some forum posts, same size and capacity, and the problem just went away. I never did understand why that fixed it.

 

[rslilly76]

@Mavster Mechanic @HeyBales

Ok here are the results from driving the 25 Fwd Hybrid today, and it's actually quite interesting to me, but also weird too!

So I have noticed from SOC 83-91% the truck will show battery at 14+ volts
I found two places LvbA and Vehicle B Battery Current that both appear to show the amps the battery is being charged at. The B one shows two decimal places while the LvbA shows only a rounded up version. (Which is why I think MM only saw it at 1 yesterday on all my snapshots, and I believe he's right it's just trickle charging)

I did notice that every time I started the vehicle these values were between 6-10 amps, but would rapidly drop down to 1-3 amps within about 5 minutes or less. (My battery SOC all day today was between 89-92%).

I noticed that while SOC is 83-91% the truck will not ramp up the charge from 1-3 amps no matter what you do, parking lights, headlights, fan on 6 or 7, or any combination of the 3. (I don't have a trailer tail light plug to test that right now).

Now here is when it gets crazy to me! When the truck hits SOC of 92% the truck actually appears to start discharging the battery! The amps go into the negative numbers, and the battery drops to 12.8 volts.

It's at this time I decided let's try the headlights, and wouldn't you know it bam! The volts go back to 14.1-14.2 the Amps jump up to 5-6 and it appears that the truck is charging the battery again. I never saw the truck go above 92% SOC but I only drove about 10 miles while this happened. If I did the parking lights, headlights, or fan at 6 or 7 the truck would keep at 14+ volts and 5-6 amps. (Judging by my calculations if the amps stayed at 5-6 the battery would have been at 100% in about an hour or so like MM has stated in some of his posts).

When I got back in the truck an hour later the truck SOC at 91% the amps stayed 4-5 and this was a first time that I have seen that happen so far. I only did 3 short trips of about 5 miles each, but each time the amps stayed at 4-5.

So I don't know what to test next, or how to test next, any suggestions on where to go from here?

 

[Mavster Mechanic]

@rslilly76

Sounds like your 2025 is behaving the same as my 2022.

Took me a long time and a lot of watching carefully to notice:

Voltage can be high 14's and you still get little to no recharging because the current (amps) were being held back to almost nil.

If I didn't see it I would not have believed it.

Cigarette plug volt meters and OBDII volt meters don't tell you health of the 12v battery! (Because it's a false reading coming from fhe DC/DC downconverter.)

Old paradigms die hard!

 

[rslilly76]

@rslilly76

Sounds like your 2025 is behaving the same as my 2022.

Took me a long time and a lot of watching carefully to notice:

Voltage can be high 14's and you still get little to no recharging because the current (amps) were being held back to almost nil.

If I didn't see it I would not have believed it.

Cigarette plug volt meters and OBDII volt meters don't tell you health of the 12v battery! (Because it's a false reading coming from fhe DC/DC downconverter.)

Old paradigms die hard!

not when yours is under 91% you can force it to charge by turning on headlights, right?

mine isn't doing that until it's at 92%

 

[Mavster Mechanic]

not when yours is under 91% you can force it to charge by turning on headlights, right?

mine isn't doing that until it's at 92%

Observe longer : more data points.
You may see it.

 

[MakinDoForNow]

Observe longer : more data points.
You may see it.

Look for the data points that show what is happening when the = 91-92% soc of 12v droping.

 

[samspritzer]

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?

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