Low 12v Battery Message

[Gros Ventre]

The other thing I think people should try first is that initial charge either right after taking delivery or buying the replacement battery. That sets up and equalizes the chemistry throughout the battery. Given the 10-12 hours it takes I believe neither Ford, the local dealer, nor the store you bought the replacement battery from will do that. They just don't want to take the time. As I've mentioned in previous trucks I've had lifetimes of 8 years. Also, since I did that on getting the system voltage warnings and replacing the battery, I've not had a peep out of the electrical system.

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[Snakebitten]

 

[Mosey]

I infer that the little battery is a "keep alive" battery for memory. Given that there is surely a diode type circuit isolator so that the small battery does not feed anything except the circuits it's designated for.

today I installed Qi charging pad from Boost Auto. Part of the procedure is to disconnect the main battery before disconnecting two harnesses running down each side. with the main battery disconnected I was able to move the power seats back and forth. So I think that little battery does more than we know.

 

[Snakebitten]

today I installed Qi charging pad from Boost Auto. Part of the procedure is to disconnect the main battery before disconnecting two harnesses running down each side. with the main battery disconnected I was able to move the power seats back and forth. So I think that little battery does more than we know.

I believe the paragraph from above implies that the auxiliary battery is in play except when the PCM sends a signal to isolate it. And that's only during high cranking Amp moments.

And actually, if I'm understanding it correctly, it's really isolating the big battery and the starter from the rest of the 12V system. So for a few seconds it is the Auxiliary battery that is furnishing 12V to the sophisticated electronics?

 

[Porpoise Hork]

I believe the paragraph from above implies that the auxiliary battery is in play except when the PCM sends a signal to isolate it. And that's only during high cranking Amp moments.

And actually, if I'm understanding it correctly, it's really isolating the big battery and the starter from the rest of the 12V system. So for a few seconds it is the Auxiliary battery that is furnishing 12V to the sophisticated electronics?

Perhaps to maintain proper voltages to electronics and maybe reduce/eliminate possible voltage spikes bleeding back through the starting circuit would be my guess.

 

[Gros Ventre]

Got it... But does this apply to the F-150 PowerBoost? I don't doubt its probable accuracy, and with all of the electronics in the F-150 maybe wiring it that way makes sense. In other words using the small battery as a keep alive battery means protecting the entirety of the rest of the truck's circuitry...

 

[Antimatter_KingRanch]

The default state of charge for the 12v battery from Ford is 80% or 12.42v. If I remember correctly the low voltage (Deep Sleep) warning is triggered when the battery drops below 50% (12.05v) charge state. This is easily hit at the temps you saw. A smart tender is about the only thing you can do to keep the state of charge at 80-100% when it's that cold. You can also go into Forscan under BCM and increase the SOC from 80 to 95% and that will help. I was off the last week and didn't drive the truck at all and even with the 16 degree temps we had the battery voltage never dipped below 12.3v when having the SOC set to 95%.

For what it's worth, I'm currently battling this with my dealer. They supposedly tested the battery as fine, yet still goes into deep sleep mode (today it did it in under 30 min after a long highway drive, it's 37 degrees out; doesn't qualify as extreme). When I got to my truck 5 hours later, I got 12.34 volts on my multimeter.... So not sure about the 12.05 volts; or it's just a software issue and the batteries aren't actually causing it. Have another appointment at the end of January, after that I'll just buy a battery myself and see (assuming they don't fix it).

 

[imnuts]

I've stated it in other threads, but I think the biggest issue for deep sleep and related battery issues isn't necessarily the battery, but the stored battery calibration. I'm sure there are bad batteries out there, but I highly doubt it's as many as people that are reporting problems. One big reason for saying that is that it affects every year/job/trim/powertrain combination out there but randomly. It's affected people that had almost no delay from build to ship, and people that were on chip hold for months, but others, life myself that were on chip hold have no issues. Some drive 5 minutes and have no problems and others drive hours and have problems.

If it were a batch of bad batteries, it would be isolated in some manner, whether it is a build timeframe, assembly plant, trim level or whatever. If it were random failures, even the worst QC at a battery plant would have found the issue and corrected it before '23s started rolling off the line. If it were a charging system issue, or electronics staying on, why does a new battery seem to fix it for most? Even fully charging a battery has fixed it for some, but not others.

Raising the target charge percentage is only a band aid. It helps, but realistically shouldn't be needed. It's also likely to degrade the battery faster as no battery wants to stay close to fully charged. Needing a battery tender shouldn't be needed either unless you're parking for a month or more without any drives.

 

[Porpoise Hork]

Raising the target charge percentage is only a band aid. It helps, but realistically shouldn't be needed. It's also likely to degrade the battery faster as no battery wants to stay close to fully charged. Needing a battery tender shouldn't be needed either unless you're parking for a month or more without any drives.

The 12v AGM car battery at full charge should read 13.0v. Unlike traditional flooded cell car batteries it is recommended to keep AGM batteries at or near full charge state when possible. Pretty much every AGM battery manufacturer recommends keeping these type of batteries SOC above 85% and left in a discharged state can lead to premature cell failure and shortens the lifespan of the battery.

With Ford setting the SOC to 80% (below the recommended 85% SOC for AGM cells) the system only brings it up to 12.5v could be considered as slightly undercharged. If a module or to fails to shut down properly and creates a parasitic drain overnight then certainly can and will lead to a deep sleep trigger event as the SOC is already degraded.

Another factor is average drive time. If someone's regularly makes short commutes 10-20 minute drives for example that could also lead to a low SOC because they are not providing the system ample time to charge the 12v battery. Over time the low battery warning and frequent Deep Sleep events can and likely will happen as a result. Increasing the SOC setting to 90-95% not only is above the recommended minimum 80% SOC but also brings the battery to 12.75v when given ample time to complete the charge and is still under the 100% charge level. This can also prevent the deep sleep events if a module were to remain active for some time after shutdown and put a draw on the battery

 

[Gros Ventre]

When I had those battery warnings on the road and replaced the battery with a NAPA AGM battery, I took the OEM battery into the dealer who then tested it. It showed to be satisfactory. I go back to that initial wetting down charge I've spoken of. Dealers or battery sales places don't do that kind of charge because it takes too much time to do. I've done that to new batteries over the years and to that NAPA AGM battery I purchased. I haven't had a single peep out of the electrical/battery system since. Note an AGM battery requires a specific type of charger. Get one and do a low rate (about 2 amps) charge on putting into service your new battery. If you have had your battery for awhile... do one of these low rate charges anyway, it'll help.

 

[Blue22]

When I had those battery warnings on the road and replaced the battery with a NAPA AGM battery, I took the OEM battery into the dealer who then tested it. It showed to be satisfactory. I go back to that initial wetting down charge I've spoken of. Dealers or battery sales places don't do that kind of charge because it takes too much time to do. I've done that to new batteries over the years and to that NAPA AGM battery I purchased. I haven't had a single peep out of the electrical/battery system since. Note an AGM battery requires a specific type of charger. Get one and do a low rate (about 2 amps) charge on putting into service your new battery. If you have had your battery for awhile... do one of these low rate charges anyway, it'll help.

I have a Noco Genius 10 charger with 12V AGM and 6V AGM charging options. Currently I use the 12V AGM option but do you think I should switch to the 6V AGM mode?

 

[Snakebitten]

I had to put a new battery in my 2012 F150 the other day. I hooked up to it with Forscan to reset the BMS.

Forscan scanned the truck.
It has 7 modules.
7
Total

My 2022 F150 has 47
FORTY more modules!

Which battery has the tougher job?
?

These are rolling computer networks with designed in parasitic draws even if every module is behaving itself. But with the enormous number of lines of code onboard, and with the relative short history of Ford's FNV architecture, there's likely to be a host of bugs?

 

[Gros Ventre]

I have a Noco Genius 10 charger with 12V AGM and 6V AGM charging options. Currently I use the 12V AGM option but do you think I should switch to the 6V AGM mode?

No. That's for a 6 Volt battery. Use the lowest amp setting it has, usually 2 amps.

 

[Gros Ventre]

I had to put a new battery in my 2012 F150 the other day. I hooked up to it with Forscan to reset the BMS.

Forscan scanned the truck.
It has 7 modules.
7
Total

My 2022 F150 has 47
FORTY more modules!

Which battery has the tougher job?
?

These are rolling computer networks with designed in parasitic draws even if every module is behaving itself. But with the enormous number of lines of code onboard, and with the relative short history of Ford's FNV architecture, there's likely to be a host of bugs?

Now I see why the auxiliary battery appears to power the whole truck during a start event... It's "keeping alive" the whole rest of the truck! Remind me to tell you about the "bit bucket" problem sometime...

 

[Blue22]

No. That's for a 6 Volt battery. Use the lowest amp setting it has, usually 2 amps.

Thanks. I had a brain fart and was thinking amps and not volts when I suggested the 6V mode.

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