Strange issues

[BLUEOVALRACER]

Offhand, I'm not sure what to say about that.

How much current does the charger maintainer put out in bulk charge mode? If it's more of a maintainer (like the Battery Tenders I use) and the battery has a low SOC, 5 hours might not be enough.

WRT the charging using the fender grounding point and the voltage dropping from 12.1V to 11.7 -- perhaps there was not a good connection at the fender ground? Is it bare metal?

FWIW, I use the battery neg(-) terminal, because it's easier and a clean connection. I'm typically just maintaining/floating an already charged battery, and the BT (Battery Tender) doesn't arc -- so there's no need to use the fender connection (it should be used for jump starts though). Our Badlands sits for days at a time so the system learns the SOC without doing a BMS reset.

No problems in 3 years.

Other possibilities are:

1) Faulty battery
2) Defective charger (not charging, meter incorrect)
3) Significant parasitic load

As for the "System Off To Save Battery", the battery really could be low, OR the BMS 'thinks' it's low (but it's not) and needs to be synchronized.

You might consider having the battery tested.

The metal was clean where the Negative Cable was connected. Next time i'll connect the cables to the Negative and Positive terminals on the Battery Like i did before. I had the Battery tested the Middle of Jan when we had the Cold Spell at Auto Zone and the CCA was right on the factory specs but IIRC the State of Charge Was Low. What's the Purpose of the BMS sounds like it's more of a Problem than good?

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[sajohnson]

The metal was clean where the Negative Cable was connected. Next time i'll connect the cables to the Negative and Positive terminals on the Battery Like i did before. I had the Battery tested the Middle of Jan when we had the Cold Spell at Auto Zone and the CCA was right on the factory specs but IIRC the State of Charge Was Low. What's the Purpose of the BMS sounds like it's more of a Problem than good?

Sounds good.

I just saw/read a good explanation of why a BMS is needed on newer cars -- particularly those with auto stop/start -- but I can't recall where it was. If I think of it I'll post it.

One reason is that -- if it works right -- it will not allow the auto stop/start to function if the battery SOC is low and it might not be able to restart the engine.

I think another is that the current draw when the BS (and other newer cars) is parked is higher than it is in older cars -- the BMS is supposed to prevent the SOC from getting too low when not being used.

 

[Mark S.]

Either the neg(-) terminal or the fender ground will work -- they are both electrically the same. Any current flow through either connection will not be sensed by the BMS.

This is incorrect, and why I posted my response. If you connect the negative lead of your charger to the fender ground on your Bronco Sport the BMS WILL sense current going to the battery.

 

[Mark S.]

WRT the charging using the fender grounding point and the voltage dropping from 12.1V to 11.7 -- perhaps there was not a good connection at the fender ground? Is it bare metal?

This would be my guess. Sometimes connections that look good aren't. I would take the nut off and thoroughly clean the cable terminal and the shoulder of the bolt where the terminal touches it.

What's the Purpose of the BMS sounds like it's more of a Problem than good?

In addition to the reasons Sherman mentioned , I believe it's also a necessity with variable output alternators. Manufacturers are trying to squeeze every bit of fuel economy they can get, and one way of doing that is limiting accessory operation. The HVAC compressor and alternator are both powered by the engine, so limiting their use reduces fuel consumption. But you don't want to limit charging current from the alternator if the battery is low, so you need a BMS to regulate alternator output.

 

[BLUEOVALRACER]

The metal was clean where the Negative Cable was connected. Next time i'll connect the cables to the Negative and Positive terminals on the Battery Like i did before. I had the Battery tested the Middle of Jan when we had the Cold Spell at Auto Zone and the CCA was right on the factory specs but IIRC the State of Charge Was Low. What's the Purpose of the BMS sounds like it's more of a Problem than good?

I had Auto Zone test my Battery again Today CCA was fine but SOC was only 46%.

 

[Dude]

I had Auto Zone test my Battery again Today CCA was fine but SOC was only 46%.

What’s your next step?

 

[sajohnson]

Nope. With the negative clamp to the fender bolt, the BMS is still in the circuit.

Well...As I said in my post that you quoted:

"It's always best to have a drawing/schematic (picture is worth 1,000 words) even for something straight-forward..."

Turns out a schematic would have saved me from incorrectly stating that the fender ground and negative battery terminal are electrically the same (a direct connection).

I was going from memory (never a good idea) and was thinking it was like (almost) every vehicle ever made with the fender connected directly to the Neg(-) terminal.

I just went out to the garage and looked, and sure enough the ground cable does appear to be connected such that any current it carries DOES go through the BMS before reaching the negative terminal -- as you've been saying.

I found this schematic:

I'm a technician (but not an automotive tech). I had forgotten I had that drawing, but I have to say that -- had I looked at it before posting -- it does seem to show the fender ground cable connected directly to the negative battery terminal -- at least it can be interpreted that way.

An enlarged view:

Different industries -- even different mfrs -- have their own schematic symbols. I'm not familiar with the one above.

That's my story and I'm stickin' to it.

 

[BLUEOVALRACER]

What’s your next step?

Not sure i Never got a Recall Notice and when Looked up Recalls with my VIN nothing came up for a Recall on the Battery. So, in my case if i buy a Battery i probably won't get reimbursed since the Battery isn't on the Recall list. Sucks since i only have 6,100 miles on my BS. So, at this Point i have a Fuel Gauge that only goes to 7/8 of a Tank when filled up the bad squeaks and rattles on the dash and the System Off To Save Battery. I really wish i would have bought a Maverick when i got this BS as i could have got an AWD Maverick XLT with the 2.0 Eco Boost for cheaper than this BS BB and i had F-150's before the BS . But i seems like when i got the BS in December of 2023 the Mavericks were pretty scarce compared to now. I might look into trading the BS for a Maverick. A couple guys on another website say they don't see many Mavericks in the Service Department with problems.

 

[Badlander1234]

2021 BS BL. Back history. Car came with an EFB battery. Battery was replaced under warranty on 11-1-2023 with an AGM Motorcraft battery, manufacturer date of 9-2023. I looked at the battery today and it says made in China.

I did get the recall letter but not sure if it will apply to the second battery.

Now to my problem. Over the last couple of months the start/stop function stopped working. That's what happened the 1st time and the battery was replaced.

Over the last 10 days or so I keep getting the message, System off to save battery on the center screen. Today I charged the battery to 100% and 12.8 volts. Drove about 20 miles and back home. I shut it off, let it go to sleep, and turned the ignition on and the message was back.

This was 4 hours later. Battery voltage was at 12.2 volts. With an AGM battery 12.2 volts is about 60% S.O.C. So, 4 hours later it went from 100% to 60%.

Alternator is charging at 14.6 volts. I disconnected the + battery cable for 5 minutes and reconnected it. This seemed to clear the message on the center screen. I'll check it again tomorrow to see if it returns. I'm guessing another battery going bad. So with the recall we'll see if it will be replaced a 2nd time on their dime. If not, I'll buy something else besides what Ford has to offer, Costco or maybe Sam's.

Another issue but I'm not sure if it's related. The passenger door touch sensor will not lock or unlock any doors. Drivers side works fine. I can lock or unlock the doors with the passenger side inside buttons, just not the outside. This started about a week ago.

Appreciate any input.

Did your dealer reset the Battery Management system after the change?

 

[Badlander1234]

There is. I'm not sure I want to reset it if the battery has issues and is going bad.

If the BMS isn’t reset, then the computer still thinks the old battery is installed.

 

[oharajoynr]

Yes, you can do the BMS reset it any time after you drop a new battery in, takes a couple of minutes. I did it after I swapped in a new battery (before the recall came out) and it's been working fine.

 

[wireman]

Did your dealer reset the Battery Management system after the change?

Well I don’t know for sure but I hope they would have that as a SOP when changing a battery. I will see if it’s listed on the work order when I get a chance.

 

[Dude]

Well I don’t know for sure but I hope they would have that as a SOP when changing a battery. I will see if it’s listed on the work order when I get a chance.

If they have it as SOP, the mobile tech that replaced my OE battery with the AGM Battery under warranty did not perform the BMS Reset procedure - no big deal so I did it myself after the Tech left

And just giving the BMS time (about 8 hours according to my Owners Manual), the BMS learns so no actual need to perform the BMS Reset but I don’t like to wait (or trust that the software works as described)

 

[BLUEOVALRACER]

Not sure i Never got a Recall Notice and when Looked up Recalls with my VIN nothing came up for a Recall on the Battery. So, in my case if i buy a Battery i probably won't get reimbursed since the Battery isn't on the Recall list. Sucks since i only have 6,100 miles on my BS. So, at this Point i have a Fuel Gauge that only goes to 7/8 of a Tank when filled up the bad squeaks and rattles on the dash and the System Off To Save Battery. I really wish i would have bought a Maverick when i got this BS as i could have got an AWD Maverick XLT with the 2.0 Eco Boost for cheaper than this BS BB and i had F-150's before the BS . But i seems like when i got the BS in December of 2023 the Mavericks were pretty scarce compared to now. I might look into trading the BS for a Maverick. A couple guys on another website say they don't see many Mavericks in the Service Department with problems.

I bought a tester at Harbor Freight and tested it Monday Temp Outside was 49 degrees Battery State Of Health was 100% and State Of Charge was 65%.Now onto the Battery in my Mustang before i charged it for a little while Sunday and Monday it was at like 33% State Of Health and 33% State of Charge. I didn't check it before i started the Mustang but it whipped the 466 BBF over fine and it started but the State of Health was still 33% but State Of Charge was 100% and it came up Replace Battery. I took the Battery to Auto Zone same thing State Of Health 33% but State Of Charge was 100%. They didn't have a New Battery Like i took out in stock and neither did 2 other Stores and the Hub.

 

[Emerald]

I installed window tint on my two front windows and ran down my battery. I used my portable charger that Ford sells and connected the neg clamp to the wrong post and it wouldn't charge my battery - panic set in. I moved the negative clamp to neg battery term and still no charge. I pulled out the manual and moved the negative clamp to the correct charging post and it started up seconds later.

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