System Off To Save Battery

[Joseph896]

Hello all,

I’m having issues with my 2019 Ranger. Within the last week or so I keep getting a “system off to save battery” message on the entertainment screen. Once it sits overnight, it has just enough juice to start it in the morning. I replaced the factory battery maybe 6/7 months ago and this has never been an issue before. I thought maybe it has a parasitic draw but not entirely sure. Any ideas? Maybe a faulty battery?

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[airline tech]

Yes, I would get the Charging System Checked along with the Battery Test and go from there as a starting point.
With the Ranger having the BMS system and how it charges may be a factor, and how often it is driven and how long of drives it gets regularly plays a factor in how it charges.
Random - short trips - The Ranger does not like, but before you dive into - trying to place the battery on a charger etc,
Get an initial evaluation on the Charging System (Operation) and Current Battery Health

Here are a couple of threads on this very subject.

Very Detailed and Lengthy (Information)

Charging Sys-Full Description-Trigger Voltages-Test Results | 2019+ Ford Ranger and Raptor Forum (5th Generation) - Ranger5G.com

Maximizing Battery Life | 2019+ Ford Ranger and Raptor Forum (5th Generation) - Ranger5G.com

 

[Rp930]

If the battery is original you are well past due.

 

[21rangerCactus]

If the battery is original you are well past due.

He states he changed it 6/7 months ago..

 

[Fordup]

He states he changed it 6/7 months ago..

Wonder if he reset the BMS.

 

[Rp930]

He states he changed it 6/7 months ago..

Oops sorry. Missed that part

 

[Dereku]

How many miles? Lots of short trips kill batteries. Mine always last 150k as I do a ton of highway.

 

[TJC]

If the battery is original you are well past due.

My battery is 5 years old and quite healthy with an Internal Resistance of 3.4 mOhm. With a few BMS tweaks (or optionally unplugging the BMS sensor), and the addition of an onboard desulfator you can easily double your battery life.

 

[Joseph896]

Wonder if he reset the BMS.

Luckily the battery was still under warranty and I went and got a new one. I didn’t reset the BMS the first time I replaced that battery. Had no idea that even existed. Put in the new battery today and reset the BMS. Hopefully that solves the issue

 

[Joseph896]

How many miles? Lots of short trips kill batteries. Mine always last 150k as I do a ton of highway.

75k miles. Lately I’ve been driving 10 minutes to work and then it sits for about 10-12 hours until I go home

 

[nolan62]

Same problem on my 2020. Original battery. I went and had a new battery put in and the problem is gone. Everything is fixed.

 

[Rp930]

Wonder if he reset the BMS.

Maybe someone can chime in. I read if it sits 6+ hours it will reset the BMS without doing anything.

 

[airline tech]

Maybe someone can chime in. I read if it sits 6+ hours it will reset the BMS without doing anything.

Sort-Of (Automatically)

The BMS system recalibrates every time the truck is shut off and the modules go to sleep.
The logic is the BCM monitors current Battey voltage and health from the BMS sensor readings.
Yes, it will recalibrate and will work the same as (Placing the battery) on a charger, the manuals state that in order to get a (accurate) reading the truck has to be in sleep mode for 6-8 hours.
However, the BCM has (1) piece of programming that pertains to the Charging Algorithm, and the self-recalibration will not set this without a (Human Input)
and that is physically doing the BMS Reset via scan tool, this will reset the (Time Since Installed) for the battery, the BCM will then treat the battery as (NEW)
I can confirm that the (Scan-Tool) BMS Reset will do this, I cannot confirm that the (Brake/Brake- Headlight Method) will do it.

Honestly, HOW MUCH of a difference it makes? IDK, but all I can say it that the BCM is not smart enough the see a new battery and change the date on its own, we know that the Time Since Installed date plays a partial role in how the BCM controls the charging system.
So yes, the (Auto) recalibration will see a fresh charge (voltage) on the battery, the same way it will react to placing the battery on a charger/maintainer, but as soon as that fresh charge is depleted the BMS system will still see a (Programed) charging algorithm as a (Older) battery and continue to charge it accordingly.

Again, all I have is a description of operation and all the manuals stating to perform the BMS reset procedure after a Battery Replacement and then bring in the various videos on how to do it without a scan tool and saying it will do it automatically if you just let it sit/rest.
That is only (PARTIALLY) true as the (Auto-Recalibration) will not reset the (Time-Since Installed) date.
I prefer the Scan Tool - Method for 1 main reason, I have a (Confirmation - MESSAGE) on the tool that is has completed, plus I have a secondary way to verify and that is the (Time-Since Installed) PID will change to (0-Days)
The manual way - all you have is a small battery light - when it goes out - the reset is supposed to be complete, did it actually reset? and did it actually reset the (Time-Since Installed) date?
Its a guessing game? as did you perform the sequence in the correct order for it to actually perform the reset?
There are too many unanswered questions in the (Manual Method)

 

[SFB]

19 Ranger XLT, I am currently on my 4th battery since new! First two were covered under warranty, I have replaced the third and now 4th. Third one was done at Ford dealership where I go, 4th I did because of being a weekend and needing the truck. We had been on a 3 week road trip in a rented RV, going into week 2 to 3 on the road I decided to check my Ford app to see what was going on, mainly curiosity but also I was concerned because of battery failures in the past. App said truck had gone to sleep to preserve battery. At that point I knew I should have disconnected the negative cable before leaving...lesson learned. When we returned I was going to pull the truck out so we could unload the RV, truck was so freaking dead it had nothing, was able to grab my volt meter and it showed 3 volts across the terminals! I think this qualifies as dead. Battery was purchased in January 2025, basically new. Meanwhile my wife goes to her Tacoma parked next to mine and it starts right up...yup I was butt hurt. Threw on the charger for an overnighter. Next morning, nope dead, battery would not recover. Battery replaced under warranty, attempted to acquire a parasitic draw, but not sure if I had the hood completely closed. I had locked the car so it would go to sleep, came back an hour later for a reading, it was showing a draw of .14 ma. Should be .05ma if Im right.
Truck has 77K, have had no other issues except the battery. On extended warranty so I'm going to have to take it in. What I hate about that is if Ford finds no issues I have to pay 200 for diag. If they do find an issue and it's covered I'll pay 100....ugh either way...

 

[got3fords]

So if it charges harder on an old battery, maybe it's ok not to reset the BMS on a new battery. Especially for short trippers.

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