Replacing the 12v battery

[Snakebitten]

That code P0B24 shouldn't be related in any way to the 12V battery.

Although it's not a code mentioned much, it's an indication of unbalanced cells in the HV battery pack. Unbalanced meaning the BECM is seeing a cell(s) that is at a lower voltage relative to the voltage of the other cells in the pack. "unbalanced".

First time might be chalked up to a glitch.
Second occurrence and I'd want the battery issue addressed appropriately.

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[Snakebitten]

I have attached the service manual procedure for the P0B24.
It's only about 4 pages and honestly is multiple attempts to get the HV battery charged back up to the higher SOC, then clear the DTC. If the DTC returns, another method of charging/balancing the cells.

After 3 or 4 methods, if the DTC reoccur, the technician is instructed to replace the battery completely.

 

[RGrove]

Yeah, I know unrelated to 12v, but I was hoping the old 12v was a source of false faults.
I've been getting p0b24 for 40k miles now. I've set up with a new dealer now, though, who says they address appropriately.

 

[Snakebitten]

Yeah, I know unrelated to 12v, but I was hoping the old 12v was a source of false faults.
I've been getting p0b24 for 40k miles now. I've set up with a new dealer now, though, who says they address appropriately.

I'm surprised that a dealership couldn't\wouldn't just follow the pinpoint procedure for the code. It's fairly straight forward and doesn't really require in special equipment.

There are plenty of warranty replacement components that are more expensive and more difficult to replace than the HV battery pack on the Powerboost.
And Ford has been equipping vehicles with a similar battery pack for 20 years. No reason to kick the can on this.

 

[Calson]

Voltage is only an indication of battery health if it is used when a load is applied to the battery. Every failed battery I have replaced over the years would show 12 volts with a meter but could not produce 12 volts with a load as with a starter motor or provide enough voltage for glow plugs.

 

[RGrove]

I'm surprised that a dealership couldn't\wouldn't just follow the pinpoint procedure for the code. It's fairly straight forward and doesn't really require in special equipment.

There are plenty of warranty replacement components that are more expensive and more difficult to replace than the HV battery pack on the Powerboost.
And Ford has been equipping vehicles with a similar battery pack for 20 years. No reason to kick the can on this.

I did specifically ask the service writer if that was Ford's diag procedure for P0B24, and he said it was. Not what you provided, but the "reset the light and see if it comes back on a drive cycle" procedure.

The truck started tonight, but had a ton of faults on the cluster, so I drove it straight to the nearest dealer and left it. The 12v battery in it was brand new and freshly charged, but it still went into battery save mode around 9pm last night. Kinda weird. I had left it in the shopping center around 6 or 7 pm.

I do love driving the truck, but it's 2 years old and I'm nervous taking it into my work sites deep in the woods now. That's not really good.

 

[RGrove]

Voltage is only an indication of battery health if it is used when a load is applied to the battery. Every failed battery I have replaced over the years would show 12 volts with a meter but could not produce 12 volts with a load as with a starter motor or provide enough voltage for glow plugs.

Yeah, I'm guessing Ford provides some kind of algorithmic/software based testing with a load bank that produces false pass, or the diag procedure applies better to standard truck parasitic loading than a hybrid's parasitic loading. The story across this forum seems to be that dealer says the battery tests good, but all the low voltage problems go away when the customer just replaces the battery themselves.

 

[Snakebitten]

The truck started tonight, but had a ton of faults on the cluster, so I drove it straight to the nearest dealer and left it. The 12v battery in it was brand new and freshly charged, but it still went into battery save mode around 9pm last night. Kinda weird. I had left it in the shopping center around 6 or 7 pm.

I hesitate to draw any conclusion or comparison between my truck and yours, but I have had the truck sitting in the barn for about 20 days. The longest ever. And about 3 days ago, even though the 12V battery was still at 12.3v, I decided to plug in the onboard Noco 5 just to protect it from getting lower.

Today I went to use the truck and although the 12V battery was completely topped off, I found that the truck was asleep and didn't respond to my approach with the FOB.
This truck is fully dolled up and it lights up like a Christmas tree as well as drops the footboards on approach.

Once I put my hand behind the door handle it did come to life.

I got in the truck and did my normal 2-step startup sequence.
Accessory mode first.
Launch OBDlink monitoring app
Press brake and start truck in ready mode.

ICE started immediately and the phone received an alert from the truck that it was in battery save mode.

That explained the no approach response, but the 12V battery was at 99% SOC after being on the Noco for 3 days?

But check out that High Voltage SOC!
33%
The BECM will not allow that low of a SOC if the truck is awake and ICE can be engaged. In fact, I don't know if I have ever seen it that low in 2 years except the one morning I got my one and only SSN alert.

I could be wrong about this, but is it possible that the truck can and will be put in battery protection mode for a low voltage state of the HV battery?

And also note that I always charge my HV battery before shutting the truck down. Sometimes that is 63% SOC. Sometimes it is 48%SOC. It depends on the BECM strategy that determines which SOC turns ICE off when in Park. (I don't yet know what determines whether 48 or 63 is going to be the target)

Regardless, something can and sometimes does tax the HV battery on a parked truck. It's fairly rare and random. I always chalked it up to OTA activity that required a period of DC/DC converter activity, but have never caught it with my logger.

I wonder if it's your HV battery that is triggering at least some of the battery save instances on your truck?

 

[Snakebitten]

I take it back on not catching DC/DC converter activity on a parked/locked/off truck.

15 day grid
May 8th and 9th had spikes of INCREASED low voltage

(Below) May 8th (24 hour grid)
Just after 10am, the LV jumped from ~12.6V to ~14.7ish

Hard to tell exactly how many minutes, but it appears to be in the 5 minute range. That has to be DC/DC converter supplied current!

And you can clearly see 2 events lasting more than 30 minutes each drawing down the AGM battery.

(Below) Next day (May 9th)
Yet another (second) event of INCREASED voltage lasting no more than 3-5 minutes?
Again, only the DC/DC converter tapping the HV battery can possibly supply that current.

So I DID finally capture evidence that explains why an HV battery SOC can drop substantially on a parked truck.
At least far more than the small amount that a large shift in battery temperature can account for. (not applicable in this instance anyway, considering Texas Coastal ambients at this time of year)

 

[RGrove]

Do you need specific hardware for that data logging? I have a bluetooth OBDII sensor hung off the truck all the time now, and use TorqueLite to pull codes and look at rudimentary info, but it can't give me that detail.
I also have a raspberry Pi wired into the truck with an ignition on/off sensor, purpose unrelated to the truck. I'd love to wire it to the can bus or OBDII port and build a dashboard or interface to log data like that on it. Never got the time to research, but when I got this truck and saw how software intensive it was, I figured there *must* be api's to interact with it.

 

[Snakebitten]

Do you need specific hardware for that data logging? I have a bluetooth OBDII sensor hung off the truck all the time now, and use TorqueLite to pull codes and look at rudimentary info, but it can't give me that detail.
I also have a raspberry Pi wired into the truck with an ignition on/off sensor, purpose unrelated to the truck. I'd love to wire it to the can bus or OBDII port and build a dashboard or interface to log data like that on it. Never got the time to research, but when I got this truck and saw how software intensive it was, I figured there *must* be api's to interact with it.

It's an inexpensive Bluetooth voltmeter attachmed under the hood on my vehicles.
Allows me to witness the static/sitting voltage without approaching or touching the truck/car

The App that talks to it is on your smartphone.

It's a made in China device, of course. So if you are concerned with data sharing, you will want to block a few DNS/IP addresses on your mobile device. I use next-dns and have 4 or 5 domains blocked for that app.

I'm not the paranoid type, but I ain't their sucker either. Lol

 

[RGrove]

I've seen that around the forum and on the YouTube channel for the DIY guy with the PB. I'm a weirdo and cant' stand an app for everything, so I haven't really wanted it. But...I can set up a voltage sensor and run that back to the Pi, and log the data through that. Some day...

 

[Samson16]

I've seen that around the forum and on the YouTube channel for the DIY guy with the PB. I'm a weirdo and cant' stand an app for everything, so I haven't really wanted it. But...I can set up a voltage sensor and run that back to the Pi, and log the data through that. Some day...

There’s a DIY guy for the PB? Is he kinda tall with hair a little longer than you’d expect and goes by the name Bruce?

 

[RGrove]

There’s a DIY guy for the PB? Is he kinda tall with hair a little longer than you’d expect and goes by the name Bruce?

No idea...just know that he has "DIY" in his YouTube handle, and he comes up a lot when I'm trying to google issues with my truck.

 

[Snakebitten]

I assure you that I wouldn't be anyone looking for a YouTube audience.

An instant loss in all credibility the moment the camera/mic captures the real persona. ?

Think hippy/cowboy that doesn't really care about any of this stuff nearly as much as it might appear.

Just having fun while I work/play/live

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