Why Does 11.7V seem to be magic number?

[Andrew-25Mav]

I"ve been monitoring my maverick the past couple of weeks, I don't drive every day, and it's cold out right now so it goes into battery save mode quickly (max 2 days). Most times it doesn't even tell me now. I come out the cabin lights don't come on. It's always started so I haven't really worried too much about it. But i've seen 12.1v being the cut off voltage, but not always, seems the truck has additional parameters it uses.

I did notice a couple of side effects of the battery going too low:

1) Brake Coach gets turned back on
2) My Oil Life reset on it's own, to 98% after 5812KM

Thats quite troubling if you are relying in ito be accurate. I'm not.

Here's my current battery stat since my last drive (3pm on the 18th), the drops are when I have unlocked the car and opened a door. It takes a while to recover, so some high current systems must activate and stay active for some time after opening. (the logging is from a customer built sensor, it is calibrated within 1.5% between 16v and 7v). And to the Fluke crowd, high-five, my best meter is a fluke 87 from 1988 (still going!).

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[Master Blaster]

Ideally, FLA and AGM batteries should be kept at 100% SOC. Obviously that's not always possible, but Ford allows the voltage to drop as low as 9.5V in some cases!:
https://www.ford.com/support/how-to...y-does-my-ford-vehicle-enter-deep-sleep-mode/

'Battery saver' is activated at a much higher voltage, but still way too low.

The owner's manual does not specify voltage or SOC that triggers warnings. I got tired of searching. The best I found is:

"Ford's Battery Management System (BMS) triggers warnings based on low State of Charge (SOC) or voltage, often around 20% SOC or lower..."

20% SOC is about 11.7V -- which corresponds with some posts here.

Anything less than 12.4 volts (close to 70% SOC) risks sulfation, lower capacity, and shortened service life.

That can happen even when everything is functioning normally, which is why it is worthwhile to use a BT.

They can be wired so that the hood does not even have to be opened -- it can be connected using a 12V SAE connector. Quick and easy.

Ford has funny ideas about what 100% SOC is. They call 100% what real battery specialists would call 80%, so you're starting from a deficit situation at all times.

 

[HeyBales]

I"ve been monitoring my maverick the past couple of weeks, I don't drive every day, and it's cold out right now so it goes into battery save mode quickly (max 2 days). Most times it doesn't even tell me now. I come out the cabin lights don't come on. It's always started so I haven't really worried too much about it. But i've seen 12.1v being the cut off voltage, but not always, seems the truck has additional parameters it uses.

I did notice a couple of side effects of the battery going too low:

1) Brake Coach gets turned back on
2) My Oil Life reset on it's own, to 98% after 5812KM

Thats quite troubling if you are relying in ito be accurate. I'm not.

Here's my current battery stat since my last drive (3pm on the 18th), the drops are when I have unlocked the car and opened a door. It takes a while to recover, so some high current systems must activate and stay active for some time after opening. (the logging is from a customer built sensor, it is calibrated within 1.5% between 16v and 7v). And to the Fluke crowd, high-five, my best meter is a fluke 87 from 1988 (still going!).

So that screen shot for OLM% is from Fordpass app.
Does the truck screen where it shows that OLM agree?

I've had chunks of time where the app data didn't update, despite miles being correct, so partial update.
If the truck was changed - very concerning and worth a dealer visit, that should be stored in memory not requiring current.

 

[Andrew-25Mav]

So that screen shot for OLM% is from Fordpass app.
Does the truck screen where it shows that OLM agree?

I've had chunks of time where the app data didn't update, despite miles being correct, so partial update.
If the truck was changed - very concerning and worth a dealer visit, that should be stored in memory not requiring current.

Brrrr. I had to go out in -14c to check. Yup the truck and the app are aligned, 97%.

I'll put it on the list of minor annoyances for the next dealer visit.

Thanks
Andrew

 

[sajohnson]

I"ve been monitoring my maverick the past couple of weeks, I don't drive every day, and it's cold out right now so it goes into battery save mode quickly (max 2 days). Most times it doesn't even tell me now. I come out the cabin lights don't come on. It's always started so I haven't really worried too much about it. But i've seen 12.1v being the cut off voltage, but not always, seems the truck has additional parameters it uses.

I did notice a couple of side effects of the battery going too low:

1) Brake Coach gets turned back on
2) My Oil Life reset on it's own, to 98% after 5812KM

Thats quite troubling if you are relying in ito be accurate. I'm not.

Here's my current battery stat since my last drive (3pm on the 18th), the drops are when I have unlocked the car and opened a door. It takes a while to recover, so some high current systems must activate and stay active for some time after opening. (the logging is from a customer built sensor, it is calibrated within 1.5% between 16v and 7v). And to the Fluke crowd, high-five, my best meter is a fluke 87 from 1988 (still going!).

Great graph!

What is the 'brake coach'?

The OLM being reset is potentially a very serious problem for those who rely on it (as you said). We drive so little that I change the oil annually, but many owners *do* count on the OLM. That's something Ford should be made aware of.

That's all the more reason to use a BT (or Battery Minder). The closer a battery is kept to 100% SOC, the longer its life.

PS: I also have a Fluke 87! I worked as a train control tech for Metro (in D.C.) and we were issued the 87. I'm not sure of the year, but it would have been around 1988. That thing is all but indestructible! I only bought the 179 because the display on the 87 was getting dim.

 

[sajohnson]

Ford has funny ideas about what 100% SOC is. They call 100% what real battery specialists would call 80%, so you're starting from a deficit situation at all times.

Needless to say, if 80% was the low limit, that would be OK, but yeah, starting from 80% and letting it go to 20% (11.7V) is no bueno.

The simplest solution for these low voltage concerns is to use a battery maintainer like a BT.

Just click on my affiliate link...

 

[Andrew-25Mav]

Great graph!

What is the 'brake coach'?

The OLM being reset is potentially a very serious problem for those who rely on it (as you said). We drive so little that I change the oil annually, but many owners *do* count on the OLM. That's something Ford should be made aware of.

That's all the more reason to use a BT (or Battery Minder). The closer a battery is kept to 100% SOC, the longer its life.

PS: I also have a Fluke 87! I worked as a train control tech for Metro (in D.C.) and we were issued the 87. I'm not sure of the year, but it would have been around 1988. That thing is all but indestructible! I only bought the 179 because the display on the 87 was getting dim.

Brake Coach (I have a '25 hybrid so not sure its on earlier years) basically gives you a score up to 100% energy recovered during braking. i.e if you can come to a complte stop using the regen you get the best score. it pops up (like most ford PIA notifications) so I've turned off. I've been driving a hybrid since 2017 and know how to get good regen results.

I'll be raising these issues with ford when it goes in for a service.

Well if you love a discharge graph, then you're going to love a 2amp battery charger graph lol.

The dip before the rise was me opening the door. I haven't touched it since so the drop out at 11:30 and 13:15 are, interesting. Maybe the voltage go high enough for the truck to start turning systems back on, the 13:15 one seems to indicate quite a bit of activity. Either that or the charger is having fun, but it's a 2amp energizer charger, which will drop to a trickle when done so I don't expect anything odd from it.

My 87 has held up very well, the LCD is still going strong. Mind you mine doesn't get a tonne of activity over the years, or spent much time outdoors in the elements. Not sure how good fluke is these days, but they were the brand to get at the time.

 

[sajohnson]

Brake Coach (I have a '25 hybrid so not sure its on earlier years) basically gives you a score up to 100% energy recovered during braking. i.e if you can come to a complte stop using the regen you get the best score. it pops up (like most ford PIA notifications) so I've turned off. I've been driving a hybrid since 2017 and know how to get good regen results.

I'll be raising these issues with ford when it goes in for a service.

Well if you love a discharge graph, then you're going to love a 2amp battery charger graph lol.

The dip before the rise was me opening the door. I haven't touched it since so the drop out at 11:30 and 13:15 are, interesting. Maybe the voltage go high enough for the truck to start turning systems back on, the 13:15 one seems to indicate quite a bit of activity. Either that or the charger is having fun, but it's a 2amp energizer charger, which will drop to a trickle when done so I don't expect anything odd from it.

My 87 has held up very well, the LCD is still going strong. Mind you mine doesn't get a tonne of activity over the years, or spent much time outdoors in the elements. Not sure how good fluke is these days, but they were the brand to get at the time.

My first choice was a hybrid -- Maverick or other mfr -- but it was my wife's turn to get a new vehicle and she really likes the look of the Bronco Sport. So, no regenerative braking.

Side note: The Metrorail trains have regen braking and put power back into the 3rd rail.

There's a lot going on with that graph, esp between ~13:30 and 14:00. I'm used to graphs like this:

Of course that's on a bench as opposed to a battery in a vehicle.

(I've seen better charts, I just grabbed that off of Google Images).

Another side note: I am very impressed with how long my Fluke 87 lasted. It got a lot of use before I retired. It was dropped more than once both inside, and out on the tracks. I looked into replacing the display but it was N/A. I do appreciate the additional features the 179 has. Some Fluke meters (incl. the 179) still say "MADE IN USA" or "Assembled in the USA of US and Foreign Components". Like you, I'm not sure if the quality has remained high. Fluke does make meters in China and other places, they may not be as good, IDK.

 

[HeyBales]

Brake Coach (I have a '25 hybrid so not sure its on earlier years) basically gives you a score up to 100% energy recovered during braking. i.e if you can come to a complte stop using the regen you get the best score. it pops up (like most ford PIA notifications) so I've turned off. I've been driving a hybrid since 2017 and know how to get good regen results.

I'll be raising these issues with ford when it goes in for a service.

Well if you love a discharge graph, then you're going to love a 2amp battery charger graph lol.

The dip before the rise was me opening the door. I haven't touched it since so the drop out at 11:30 and 13:15 are, interesting. Maybe the voltage go high enough for the truck to start turning systems back on, the 13:15 one seems to indicate quite a bit of activity. Either that or the charger is having fun, but it's a 2amp energizer charger, which will drop to a trickle when done so I don't expect anything odd from it.

My 87 has held up very well, the LCD is still going strong. Mind you mine doesn't get a tonne of activity over the years, or spent much time outdoors in the elements. Not sure how good fluke is these days, but they were the brand to get at the time.

I'm wondering if you caught a BMS Relearn in there. Was it locked after the door opened?
Been 5 hrs since the door if it was locked, enough time for it to think surface charge since last use is gone. Maybe doing it's little measurements on a known draw.

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