Low 12v Battery Message

[Sky111]

@SemperVee - it is not 60-70%, the factory default is 80% and it can be adjusted using Forscan.
I set mine to 99%, and then reset BMS.

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[SemperVee]

Thanks for the info.. I don't currently have access to Forscan being a MAC guy. Any other way to do reset the BMS higher?

 

[HammaMan]

See my post here on how the PB charging system actually works....
https://www.f150gen14.com/forum/thr...arter-generator-engaging-12-8-to-14-5v.14709/

 

[scott011422]

So where is Ford getting this 85% SOC? I'll just spoke with Odyssey and Interstate and both wanted their batteries as close to 100% as possible. Even searching the internet, Main consensus is 100% for AGM for long life.

 

[scott011422]

I'm still struggling with this low battery issue. All loads i'm seeing with the truck off are good. Using voltage and battery checkers the battery tests good. I still think there is a capacity issue with the battery since it charges from 11.9 to 12.8v in less than 2hrs at 3.5a max charge.

Only other thing I could do battery wise is check the reserve capacity and I don't have that equipment, Nor do I want to spend 200+ dollars to check a 250 dollar battery. But if 3.5ah takes the battery from 11.9 to 12.8 in two hours, There is no way that battery is going to last 2.5 hours with a 25amp load on it.

I could check the amperage the truck is putting back into the battery, But sadly, my equipment doesn't read past 10 amps. (Truck idles at 16a)

Anyone have any ideas for further testing?

 

[Sky111]

Costco has a good return policy (and warranty!) on the batteries.
I agree with you that if battery voltage goes up during charging too fast, something is not right.
I upgraded my H7 with H8 from Costco, and now voltages are a bit more stable, but truck still manages to drain the battery (judging by the voltage when the truck is off/settled).
When I have the truck on, the voltage on the battery quickly goes to 14.90, then stays about 15.10V (as per my bluetooth meter - not sure how accurate it is), so Powerboost definitely charges the 12V battery when it is on.

I am wondering if there is ANYTHING in Forscan configuration options that we can modify to trim down "settling down after the truck is off" time. So instead of current 15-30 min of draining 8-5A, reduce it to 5-10 min max?

 

[TheArborist]

Just a quick update. The truck hasn't given us any grief since putting the rear aux battery on a Noco Genius G3500 overnight.

It seems a good slow charge is what it needed. Needs to pass the -40 test before I'm confident but there's hope!

 

[scott011422]

Thats interesting. Did you ever charge the main battery with the power leads still attached? I ask because if so, you have kinda charged that battery in the past. With the truck off, it is connected to the main battery.

 

[Old Bear]

Just a quick update. The truck hasn't given us any grief since putting the rear aux battery on a Noco Genius G3500 overnight.

It seems a good slow charge is what it needed. Needs to pass the -40 test before I'm confident but there's hope!

I was planning to hook up leads to the engine compartment battery and figure out where to route the connector for outside access today, but this stopped me. I liked my setup on my Super Duty where I hooked up a 2 amp Battery Tender to the OBD port and laid the charger on the floorboard. The door seal didn't bother the power cord, and I didn't have to worry about theft. But the OBD port has a max 3-amp limit so that is a no-go for the charger I got for the KR. Then I was going to use the 12-volt outlet until someone determined that it shuts off when the truck goes to sleep.
You are saying that we can maintain the charge by connecting to the battery under the back seat. That gets me back to having the charger locked up in the truck! Have you been able to verify that hooking up this way does charge the under-hood battery as well? Crossing my fingers here!

 

[RickBullotta]

Beginning to wonder if the Ford OEM battey is the problem. Thanksgiving weekend a year ago I had some battery alerts. Since it was Thanksgiving weekend with much travel for family get togethers, I located a NAPA store along my route and bought a replacement AGM battery. Finished travels and on return home did the low rate "wetting down" charge I've spoken of. Have had zero peeps out of the electrical system since. Had that OEM battery checked out by my dealer and it was reported OK. Still, am curious if those who've had these issues have replaced their battery and whether a new, non-OEM battery made a difference.

Swapping out for a Duralast Platinum solved my issues. I don't understand why so many people keep banging their heads against the wall when an easy and (relatively) inexpensive fix has worked for so many of us.

 

[RickBullotta]

I'm still struggling with this low battery issue. All loads i'm seeing with the truck off are good. Using voltage and battery checkers the battery tests good. I still think there is a capacity issue with the battery since it charges from 11.9 to 12.8v in less than 2hrs at 3.5a max charge.

Only other thing I could do battery wise is check the reserve capacity and I don't have that equipment, Nor do I want to spend 200+ dollars to check a 250 dollar battery. But if 3.5ah takes the battery from 11.9 to 12.8 in two hours, There is no way that battery is going to last 2.5 hours with a 25amp load on it.

I could check the amperage the truck is putting back into the battery, But sadly, my equipment doesn't read past 10 amps. (Truck idles at 16a)

Anyone have any ideas for further testing?

CHANGE THE BATTERY! You've already spent well over $200 in time and effort. If you're still running the OEM battery, the solution is easy.

I have not heard of anyone (yet) who replaced the OEM battery with a quality aftermarket battery and continued to have issues.

 

[scott011422]

CHANGE THE BATTERY! You've already spent well over $200 in time and effort. If you're still running the OEM battery, the solution is easy.

I have not heard of anyone (yet) who replaced the OEM battery with a quality aftermarket battery and continued to have issues.

I 100% agree with you. However it is hurting my soul that I haven't found anything actually wrong yet. And I know me, Once I replace the battery, I wont care anymore. I also know with what I've seen during testing that without a really good relationship with your dealer, That would change it just to make you happy, They are not replacing the battery since there is nothing wrong with it. I've don't more testing than they would and things still look great.

Thats all. More of a logic puzzle. 2+2+2+2+2+2 isn't equaling 12. its only 11.

 

[RickBullotta]

I 100% agree with you. However it is hurting my soul that I haven't found anything actually wrong yet. And I know me, Once I replace the battery, I wont care anymore. I also know with what I've seen during testing that without a really good relationship with your dealer, That would change it just to make you happy, They are not replacing the battery since there is nothing wrong with it. I've don't more testing than they would and things still look great.

Thats all. More of a logic puzzle. 2+2+2+2+2+2 isn't equaling 12. its only 11.

I feel your pain. I can't leave a good puzzle unsolved. Usually. Unless not solving that puzzle would leave me stranded.

 

[TheArborist]

Thats interesting. Did you ever charge the main battery with the power leads still attached? I ask because if so, you have kinda charged that battery in the past. With the truck off, it is connected to the main battery.

Yep, I tried charging both units from under the hood a few times. Tried both sides of the BMS sensor but it never fixed the issue.

The dealer disconnected the bigger 12V battery to slow charge it after my first trip in. They didn't touch the aux battery so I decided to do the same back there and I haven't had any issues since.

The only reason I saw for disconnecting the rear battery is that my charger recognizes the smaller cell and charges at 0.9A accordingly.

 

[DcnPat]

I'm still struggling with this low battery issue. All loads i'm seeing with the truck off are good. Using voltage and battery checkers the battery tests good. I still think there is a capacity issue with the battery since it charges from 11.9 to 12.8v in less than 2hrs at 3.5a max charge.

Only other thing I could do battery wise is check the reserve capacity and I don't have that equipment, Nor do I want to spend 200+ dollars to check a 250 dollar battery. But if 3.5ah takes the battery from 11.9 to 12.8 in two hours, There is no way that battery is going to last 2.5 hours with a 25amp load on it.

I could check the amperage the truck is putting back into the battery, But sadly, my equipment doesn't read past 10 amps. (Truck idles at 16a)

Anyone have any ideas for further testing?

I'm with the other guys who think you may have a bad auxiliary battery. If it is bad, it would put a constant load on the main battery and easily cause the discharge you are seeing overnight.

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