Hello all.

I broke my ankle a few weeks ago, and I have not been able to drive. Today I finally was going to go for a ride, and when I went to start the truck the battery did not have enough juice to start. The console said, "Shutting down to preserve battery" or something like that. It has been 3 weeks since I drove or started the truck.

Can the computer etc. drain the battery? Is this a known issue?

 

Welcome to the forum

What year Ranger?

Far more likely the battery is just older than 5 years and is now self draining
If so these work fine if recharged every few days(driven) but when left longer they drain down

How old is the battery?

Once you get vehicle started or battery recharged, wait 4-6 hours and test battery voltage, 12.3 to 12.8v is expected, write it down
Unhook either battery cable after testing
wait 8 hours or so and test battery voltage, if its lower then battery IS self draining, replace it
If its the same then you will need to hook up AMP meter and start pulling fuses, one at a time, to see when amps drop blow 100mA or 0.1amp

Depending on year of the Ranger key off amp draw should be 0.03 to 0.07amp, 30-70mA
This amp draw is for clock time, computer memory and Keyless entry, and would take about a year to drain battery down far enough for a No Start

1995 and up have a Battery Saver relay, which doesn't turn off power for 30-60min after key off, so you need to pull out its fuse to do amp draw test without waiting
Tell us the year of Ranger and we can tell you what fuse to pull for testing

 

The battery is 3 years old. came new with the truck. I highly doubt a battery is bad after 3 years, but I will check it.

 

New Battery can fail this way

Very simplified version
Car batteries use + and - plates, when charging the battery "ions" move from one plate to the other(storing a charge), when discharging the "ions" move in opposite direction
Every time you charge and discharge "ions" can "stack up" one on the other, causing a thread sticking out on a plate
If two threads ever touch from + to - then battery becomes self draining
When you drain a Car battery too much more threads are built, Deep Cycle batteries are made for this, different plate design, car batteries are not

There also the "debris" issue, charging and discharging cause a build of of debris at the bottom of battery, if debris reaches bottom of + and - plate then a short and self discharge
If a new battery was not fully cleaned or there is a "warped" plate then self discharge

Over charging is also an issue, can "warp" plates or cause faster debris build up
So bad alternator can drain battery or overcharge battery, either shortens the life of the battery

But easy enough to test battery first and then move on, or find out it is the problem and not waste time on amp draw test

 

Thank you Ron,

It is a 2019 XLT 4x4, I called the dealership and they said that I could come in for free and they would test / replace the battery if needed, but I doubt a 3 year old battery would already be faulty? Thank you for the information about typical amp draw, that is one thing that is easily tested.

I was more curious if the computer memory / keyless entry etc. would drain a battery in 3 weeks, thank you for the info. That helps a lot.

 

I think there was an issue with 2019 and 2020 Ranger(Ford) batteries and charging system

Google: 2019 ford ranger battery keeps dying

The 0.03 to 0.07amp draw is for 1995-2011 Rangers
The 2019-2022 Rangers will be higher as they have way more electronic memory to keep

 

Yes thank you very much. I fully charged the battery, then did the tests you suggested. Amp drain is significantly higher (.125) but even still that should take about 6 months to drain a battery to where it will no longer start, not the 3 weeks (ish) I have been out. I am probably going to chalk it up to short in-town drives. I live in a small town and do a lot of errands, therefore it does not always run for the ~19 mins needed to charge after a start. It was fine as long as I did those every few days, but over the course of the month it might have gone below the amperage needed to start.

Furthermore, I changed a few settings, like the light turn off down to 10 seconds instead of the 2 minutes, and other battery draining features. Hopefully this helps any other 2019 users.