Ford BMS issues, research, testing, and solution results

[Ghurst]

So long story short…. Replacing the BMS sensor for a newer version made no difference? That’s disappointing…. I was ready to go out and replace the sensor on my job1 21 king ranch. Looks like another new battery and continuing to live with my low soc. See if I get more than 18 months out of the new battery! Extremely frustrating!!

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[SilverPigeon]

So, the weekend's fun with the BMS:
- Friday afternoon disconnect charger, KOEO: 77% @ 12.1V
- Friday evening arrived at destination, KO then KOEO: 83% @ 12.1V
- Sunday morning KOEO: 21% @ 10.9V, no crank.
I always carry a lithium jump starter so no problem when leaving Sunday afternoon. I do have to post this next photo because I've never seen this before. Approximately 1 hour into the drive home (KOER):

Some observations:
- It has never been to 100% before, ever. Notice that:
- the alternator is still pushing amps into the battery;
- still did so for the entire drive home although it ramped down to 1A
- the alternator is working its guts out, with 7A more than the typical 45A-ish being the norm on my truck

Some conclusions:
- the OBD Fusion Ford/Lincoln/Mercury PID for estimated SOC% must max out at 100 because my modified charging parameters have SOC% at 120; if it was only a true 100, there wouldn't be any current going into the battery
- It seems that the (effectively) complete discharge of the battery over the weekend has somehow woken up the BMS (or BCM?) to finally start taking notice of my modified charging parameters.

As usual, I will keep the truck on trickle charge at home and if anything odd happens, I'll let you know. I'm not bothering to put back the original BMS but it's stored away for a spare

 

[Ricksc]

Bought new battery put on maintainer for 2 days. Installed and reset BMS with forscan. As of now setting at 81%. Will let it sit today and check tonight.

 

[CCDF150]

Maybe a captain obvious question here but dont fully understand the OTA process…

Trying to outsmart the brains of my truck to extend battery life.
Truck is a garage queen - mostly in storage for future adventure in retirement.
22 Coyote.
Just swapped battery for a fresh H7 and reset BMS.

Thinking through if there is anything I can do to manage parasitic draw while it sits.

Does the automatic software update or scheduled update setting cause truck to wake up while stored? Would disabling this while in storage help preserve battery SOC?

 

[Ricksc]

Only thing you could do for long term sitting/storage would be add a battery maintainer. There’s too many computers on these trucks that suck battery juice.

 

[CCDF150]

Right…Unfortunately Maintainer not an option as I don’t have any electrical service in storage.

What about disconnecting battery altogether while in storage? Is there any downside to taking it off grid for an extended time? Would truck just wake up where it left? Reset the BMS on eventual startup and all good?

 

[Ricksc]

You should be fine pulling battery. My 22 hasn’t got updates in a while. I would at least hook up battery and drive it monthly to keep fluids moving and gas fresh

 

[tomcaudell]

Please keep this thread going, I have a 23 5.0 XLT 4x4. Have had many problems with the low battery alert and half down loaded software updates. Left the truck overnight at dealership to have them charge and test battery. 80+ mile round trip. Only to say battery is fine. Just have to live with it I guess. The slow engine turning over and barely starting until today. After driving 15 miles to store came out and it wouldn’t start luckily I had some cables and a nice gentleman who jumped started the truck. I just went to Wally World and got the cheapest AGM h7 they had. I like the truck and if I have to spend $189.00 plus tax every 2 years to drive it I will. When it’s time to replace it. I hope GM has sorted there v-8 nightmares. My 2018 Denali duramax starts after sitting 8 months. Just saying.

 

[Ricksc]

If they would test for SOC then the battery would fail the test. Yes it’s a PIA.

 

[Davexxxx]

I read through the thread once but can it be summarized?

As I recall, this new part, was hoped to be a cheap, easy and obvious fix but wasn't. Right?

 

[Ricksc]

Correct changing the part did nothing. At least on my truck.

 

[Ricksc]

My next move is to change the power port/cigarette lighter socket to hot as long as I can. Then add a solar charger that I put on dash when parked.

 

[Davexxxx]

My next move is to change the power port/cigarette lighter socket to hot as long as I can. Then add a solar charger that I put on dash when parked.

If you can get that plug off the timer, I have done that in our old Cass B camper, to keep the coach batteries maintenance charged.

 

[Ricksc]

There’s a Forscan setting I have found, hopefully that will work. If not I will just run wires to battery

 

[Porpoise Hork]

I read through the thread once but can it be summarized?

As I recall, this new part, was hoped to be a cheap, easy and obvious fix but wasn't. Right?

Seems to be hit/miss from the results others have gotten. For some like myself who's primary issue was random overnight large SOC drops, the updated BMS seems to be a solid fix. For others especially the non PB owners, Ford's anemic charging strategy rears its gnarled head and looks to be a major contributor to those trucks not being able to maintain the set SOC.

I mean I get why Ford is trying to squeeze as high an average mpg across their fleet as possible so they can hit EPA standards to reduce the fines as much as possible for missing the mark. The thing is none of the other car brands on the market appear to have as much trouble maintaining battery SOC levels. Take my wife's Kia Sportage for example. It'll sit parked in the garage for days on end and never has an issue with battery SOC levels. Start it up and let it idle and even with the hvac off it's pumping 13.8-14.5v into the battery all the time and easily keeps the battery at 100% SOC. Compare that to ours where we're lucky to get 12.8v unless we trick it to increase voltage draw and for many still struggles to keep it at 80% regardless of what the SOC is set to.

Unless Ford releases some smaller reliable ultra high MPG cars to offset the low numbers because about all they make now are trucks we're stuck dealing with this crap. Well that is unless someone can come up with a way to reprogram the ridiculous base charging strategy Ford's genius engineers set and actually pump current into the batteries...

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