Ford BMS issues, research, testing, and solution results

[Ricksc]

Don’t tempt me looking at the super duty’s as we speak

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[Snakebitten]

Don’t tempt me looking at the super duty’s as we speak

They are awesome.
Both the gas and the diesel.
Amazing trucks for getting the job done.

But jumping out of the F350 back into the Powerboost is like getting off the tractor and sitting in a Lazyboy.

If I was forced to settle for just one truck, I would not be miserable or unhappy with either. But they are more different than they are the same, if that makes sense.

Keep in mind there are shorter (more manageable) and less stiffly suspended SuperDuty trucks than the one I purchased.

 

[Ricksc]

I had a 92 f250 7.3 diesel. Loved it!

 

[Ricksc]

I can buy a lot of batteries for $80000.

 

[Porpoise Hork]

I can buy a lot of batteries for $80000.

I just half choked on my coffee...

 

[Ricksc]

Seems like for those of us that don’t drive far daily or use truck often we are screwed. Yes a maintainer will work if you live where you can do it. I only have street parking and sometimes not close to my house. Would A bigger alternator help if you can get one?

 

[Jmitchelltfo]

Seems like for those of us that don’t drive far daily or use truck often we are screwed. Yes a maintainer will work if you live where you can do it. I only have street parking and sometimes not close to my house. Would A bigger alternator help if you can get one?

Check out Mechman. They offer a rebuild service or you can check with them about their higher end stuff.......only show compatibility up to 2020.


https://www.mechman.com/f-150/

 

[Porpoise Hork]

Seems like for those of us that don’t drive far daily or use truck often we are screwed. Yes a maintainer will work if you live where you can do it. I only have street parking and sometimes not close to my house. Would A bigger alternator help if you can get one?

Unlikely would make that much of a difference since the BCM still controls the charging strategy. Also If I remember correctly Ford installed a 200 amp alternator. There are 300 amp after market alternators available but if the BCM is directing low amp output from the alternator even when the SOC is well below the set point then installing a beefier one may not help much.

The biggest issues it seems for non-PB's are with short drives, parasitic drain, and lack of ample battery reserve. The PB uses the aux battery via the isolator to supply power to the truck after key off and module shutdown cycle has completed. In the event the aux battery SOC gets too low the system then pulls from the primary 12v and/or HV battery instead. This would explain why the PB is able to maintain a hich SOC at or on the set point and non-PB struggle so much. Ford really should have included the same aux battery setup in the non PB.

 

[skiteton]

This thread is eerily timely for me. I had plenty of electrical issues with my 22 PB and have had zero issues with my 24 PB up until this last weekend. The truck sat for 4 days in my garage, ~55-65° temps, and when I started it on Sunday, the chimes/tones were the "brash" sounding type. I got the "System Off to Save Battery" message. The truck was driven for 35 miles in Sport mode and no change to the chimes and I still got the battery message. Driven another 35 miles in Tow/Haul and no changes. See pic below for LV SOC during my commute to work this morning. How does this happen out of the blue? My truck has often sat idle for 4 or more days and this hasn't happened before. I'm hoping for a quick fix to bring it back to "normal".

 

[Ricksc]

It’s not out of the blue, it’s slowly been loosing SOC until it reaches this point. Then this happens.

 

[Snakebitten]

If I had a non Powerboost, I would be happy to experiment with adding a small LFP auxiliary battery, sans the isolator, and do some testing.

I have no doubt that it would likely elevate the resting voltage of the truck above what the standalone AGM would be.
But it wouldn't fix issues related to parasitic draws from modules not going to sleep like they should, or weak AGM starter battery.

 

[Ricksc]

If I had a non Powerboost, I would be happy to experiment with adding a small LFP auxiliary battery, sans the isolator, and do some testing.

I have no doubt that it would likely elevate the resting voltage of the truck above what the standalone AGM would be.
But it wouldn't fix issues related to parasitic draws from modules not going to sleep like they should, or weak AGM starter battery.

I have thought about this but it’s over my head in how to make it all work together.

 

[Snakebitten]

I have thought about this but it’s over my head in how to make it all work together.

If I had to guess, with a non Powerboost (no LFP Auxiliary) the equivalent resting voltage would be ~12.7-12.8
But what should be the same, no matter what, is how flat it should sit overnight.

Here is midnight last night until now:

I think you have to address your rapid decline first.

 

[Mosey]

Here is my SoC plot from yesterday. Started the day at 50% until I put it on the Noco. I went on a short drive, 7 miles. When I reached my destination the SoC had dropped to 98%. I hopped back in the truck about an hour later and the SoC was at 70%.

I know systems stay awake for a while after the truck is shut down, but dang. I then held at 70% all night.

I have installed a new BMS sensor dated 2024. The truck is a 21 so maybe it’s time for a new battery.

 

[Snakebitten]

I haven't seen those graphs in SOC vs voltage before. Interesting.

If you have the oem battery in a 2021, at this point, you've done well!

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