12 Volt bed outlet - what can it safely power?

[Tbone289]

I didn't see it mentioned if you did the opposite experiment - Shutting down your truck without anything being powered on the bed plugs and then testing to see if you have voltage.

I tried to address this in post #38, but it probably wasn't clear enough, so i will be more detailed:

I can shut the truck down without any accessory loads plugged in, and accessory power remains on. One example where I frequently use this is I turn off the ignition without any 12V loads when I reach my destination, exit the truck, lock the door, open the tonneau cover and switch on my custom bed lights for loading/unloading. The lights are run through the accessory bed wiring access and are powered until the timer runs out at 75 minutes. If I need to continue to use those lights after the timer runs out, I unlock the door, turn the key to on, then off, remove the key and lock the door again. This turns the 12V accessory power on again and resets the timer, giving me another 75 minutes of use without the key in the ignition. I can reset like this again and again, and it will work until the minimum battery SOC is reached.

The "on time" for the timer is configurable by seconds in the BCM, or at least it is for MY'22-'24 Mavericks. @MaverickDragon how does this configuration work with your situation where the 12V power is off when the ignition is turned off? What I'm unclear about is, if your accessories are never powered on without the truck powered on, how does the timer ever come into play? Does the timer configuration exist in the 2025+ BCM?

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[MaverickDragon]

Stardate 41153.7 -
Mission complete.
The Bed Plug Incident:
Truck turned on / off with no load on bed plugs= No power to plugs after shutoff.
Minimal load (12 volt test light) on power plug with ignition on.
Power remains on after ignition is off.
Vehicle performing as designed.
Issue terminated.

 

[Tbone289]

There is no point from a programming perspective to keep power on with a timer when nothing is using power.

Well, my example above with the bed lights is one where I would want power to remain on without a load. I would argue that if there's no load on the circuits, there's no need to disconnect them as there's no cost to the battery SOC, so why power them down immediately? You are protected from running the battery down on accident anyway.

 

[SafetyGuy]

I doubt you need to troubleshoot anything, as your vehicle seems to be operating normally.
I think mine is as well. There is no point from a programming perspective to keep power on with a timer when nothing is using power.
It is unlikely to make a difference as to how significant of a load is on the 12 volt system, just that it has one to keep the power on with the timer.

I expect thst when I hook up a test light to my pigtail adaptor that I'll have power when I turn off the truck.. I'll post results either way when I have something to report.
Cheers

Good day

Troubleshooting is a fun exercise and to me doesn't mean there is a problem...the fun is the figuring out what is happening and why.

If I had a truck on the opposite side if the fence in this problem, here is what I would do.

(First, before beginning ensure your 12 volt battery is in a fully charged state...mine is almost always over 12.8 volts 12 hours after shut down. This is good enough for the girl I go out with.)

1-it seems that those that report having the 12 volt power go off immediately on ignition off, I would meter the rear power port or even the interior power port...it is my thought they are are all on the same circuit and should read the same...none...I would meter both, in case I am incorrect in my thoughts.

I could be incorrect on my assumption, but let's just continue till someone can definitively answer this, as I don't have the wiring diagram and probably wouldn't read it properly anyways. (See prior post on this area is not my forte ;-).

2-turn on truck for several seconds and turn off, open and close driver door to shut truck down. Then meter 12 volt ports to confirm voltage, or absence of voltage.

3-insert a simple voltage meter into the interior power port/rear port, if there was no power before, does the meter complete the circuit and power is restored for the mentioned 70/90 minute period?

( I do not expect this to happen, but this is testing so everyrhing needs to be checked.)

Note findings and readings if any.

4-start again. This time before anything, insert voltage indicator into power port (check one at a time and repeat for all power ports you have available). Turn truck on for several seconds and check each port to see if any of the power ports are remaining powered once power is turned off and driver door is opened and closed, to shut the truck down.

If you have read all of this, you get the idea...slowly add loads and see if there is any change in power being kept on at any time, where there was no power being metered previously. I am not expecting any change in my truck, but that only means I need to check to confirm.

Ahhh, fun with electricity...is anyone else in for this exercise?

After tapping this out on my phone, I think I will go to my garage and actually do the test on my truck!

I will just need to disconnect a few things to remove 12 volt power demand and I will meter to check on power. (Spoiler, I think I did most of this already, months ago when I was checking things out...but will now do it specifically to test this all out myself)

I will come back and post as to my results later today, if all goes well.

Cheers

Andy

 

[MaverickDragon]

Well, my example above with the bed lights is one where I would want power to remain on without a load. I would argue that if there's no load on the circuits, there's no need to disconnect them as there's no cost to the battery SOC, so why power them down immediately?

What you want is a different question, but apparently that is already working for you.
I suspect that ANY load on the 12 volt accessory system will keep the accessory power on with the timer after shut down.
My truck detected a test light which is a very tiny fraction of a watt, and that kept the power on after vehicle turned off.

Perhaps even a battery monitor with a seemingly negligible load, or even a sensor for the bed lights if it has a motion detector would do it.

If there is no load to support, there is no point in running a timer to terminate the power that isn't needed. You are right, no savings by turning off unused power but there is power needed to run a timer that isn't needed because no power is used.
I suspect that's why it works that way in my model year. Yours could be different, but then there were a "few" battery issues noted, and perhaps this was a change. Maybe not.

None of my other vehicles keep accessory power on at all after shutdown, so to me, the way the Maverick works is not a problem.

I use battery LED's for those few times I need light in the truck bed.
Your bed lights work for you. That's great for both of us.

 

[Tbone289]

Perhaps even a battery monitor with a seemingly negligible load, or even a sensor for the bed lights if it has a motion detector would do it.

I suspect that this is correct. To that point, my wife occasionally keeps a USB charger in the front power point that has an LED in it. There is a possibility that was plugged in during some of the cases where I noted my truck's turn-off behavior. I will check that this evening and test with that charger plugged and unplugged and report back.

If it turns out mine actually does work like yours (despite my insistence over and over that doesn't ) , then I just have to ensure that charger is plugged in to have the desired effect.

@MaverickDragon, I should add that the bed lights have a purely mechanical switch, so the USB charger is the only possibility for being the triggering load.

 

[MakinDoForNow]

I tried to address this in post #38, but it probably wasn't clear enough, so i will be more detailed:

I can shut the truck down without any accessory loads plugged in, and accessory power remains on. One example where I frequently use this is I turn off the ignition without any 12V loads when I reach my destination, exit the truck, lock the door, open the tonneau cover and switch on my custom bed lights for loading/unloading. The lights are run through the accessory bed wiring access and are powered until the timer runs out at 75 minutes. If I need to continue to use those lights after the timer runs out, I unlock the door, turn the key to on, then off, remove the key and lock the door again. This turns the 12V accessory power on again and resets the timer, giving me another 75 minutes of use without the key in the ignition. I can reset like this again and again, and it will work until the minimum battery SOC is reached.

The "on time" for the timer is configurable by seconds in the BCM, or at least it is for MY'22-'24 Mavericks. @MaverickDragon how does this configuration work with your situation where the 12V power is off when the ignition is turned off? What I'm unclear about is, if your accessories are never powered on without the truck powered on, how does the timer ever come into play? Does the timer configuration exist in the 2025+ BCM?

If the 12v battery soc (as computed it will be when the battery settles(!)) then the delay timer is not activated because 12v is "seen" as too weak.

 

[Tbone289]

If the 12v battery soc (as computed it will be when the battery settles(!)) then the delay timer is not activated because 12v is "seen" as too weak.

Yes, and that is why I stated, "I can reset like this again and again, and it will work until the minimum battery SOC is reached. "

 

[SafetyGuy]

That is odd. Both my 22 and 25 had lights in the bed that I installed. They are off until I go to get the groceries out of the back at night and turn on when I flip the switch and the truck is off? Maybe your battery isn't fully charged? I went to the drive in the other week and had to leave the truck on so it could cycle on and off to charge the battery. Message came up on screen that the radio would turn off due to lower state of charge if engine was not on and could charge.

Good day, @Tailender

I am now circling back to your post...I read it earlier when you posted it, but have been working on other things till now (and have had time to ponder over it).

So, you said you left your "power on" while you were at the drive in, and this was to charge your battery. You then state that a pop up came up to say the radio will turn off...etc.

Now, my first thought is that possibly you turned your truck off after arriving at the drive in, and then just pressed the power button/ignition without pressing the brake?

This would logically explain everything that occurred and when it occurred.

By only turning on power (only running off the HV battery) as in the accessories setting, the truck was not in a state or condition where the truck engine can and will cycle on and off as needed, to keep your HV battery sufficiently charged as you use it.

Your explanation sounds like you only had the HV battery in use and you depleted it...the truck engine could not cycle on and off so the truck was letting you know it needed to shed electrical loads till you pressed the brake/turned on the engine and allowed the engine to run when electrical demands dictated it.

Again, this has been my conclusion thus far, as to the only way to get that pop up...I have run my hybrid like this many times while waiting for my wife, and the engine comes on and turns off as the truck is monitoring my HV batteries state and knows when to cycle.

I imagine that if I only ran off the HV battery for a long enough period that I would get a similar pop up, depending what I was using at the time.

The only way to confirm if your truck is operating properly is to take the time and test it.

Go out, foot on brake and start it...only HV battery should come on initially unless you already drained it the last mile before arriving at home (I do this every time to max electrical drive usage).

If your truck in this condition cycles properly you are good to go, if the motor does not eventually cycle on and off, you might have a bigger issue and a dealer appt would be the next course of action.

It all depends on your testing of your trucks system.

Please test it out and come back to let us know...as I have stated in other posts, I am a curious person and your experience has drawn my attention and if it was operator error, that is okay...we all have those. If you have a bigger issue, maybe this could help sort it out.

Cheers, and good luck...I am hoping for operator error and not a bigger problem.

Andy

 

[Tailender]

Good day, @Tailender

I am now circling back to your post...I read it earlier when you posted it, but have been working on other things till now (and have had time to ponder over it).

So, you said you left your "power on" while you were at the drive in, and this was to charge your battery. You then state that a pop up came up to say the radio will turn off...etc.

Now, my first thought is that possibly you turned your truck off after arriving at the drive in, and then just pressed the power button/ignition without pressing the brake?

This would logically explain everything that occurred and when it occurred.

By only turning on power (only running off the HV battery) as in the accessories setting, the truck was not in a state or condition where the truck engine can and will cycle on and off as needed, to keep your HV battery sufficiently charged as you use it.

Your explanation sounds like you only had the HV battery in use and you depleted it...the truck engine could not cycle on and off so the truck was letting you know it needed to shed electrical loads till you pressed the brake/turned on the engine and allowed the engine to run when electrical demands dictated it.

Again, this has been my conclusion thus far, as to the only way to get that pop up...I have run my hybrid like this many times while waiting for my wife, and the engine comes on and turns off as the truck is monitoring my HV batteries state and knows when to cycle.

I imagine that if I only ran off the HV battery for a long enough period that I would get a similar pop up, depending what I was using at the time.

The only way to confirm if your truck is operating properly is to take the time and test it.

Go out, foot on brake and start it...only HV battery should come on initially unless you already drained it the last mile before arriving at home (I do this every time to max electrical drive usage).

If your truck in this condition cycles properly you are good to go, if the motor does not eventually cycle on and off, you might have a bigger issue and a dealer appt would be the next course of action.

It all depends on your testing of your trucks system.

Please test it out and come back to let us know...as I have stated in other posts, I am a curious person and your experience has drawn my attention and if it was operator error, that is okay...we all have those. If you have a bigger issue, maybe this could help sort it out.

Cheers, and good luck...I am hoping for operator error and not a bigger problem.

Andy

I believe when I got to where I was parking, I kept my foot on the brake, put it in park and turned the key to power accessories. It turned the gas motor off. It was about 5 to 10 min that the warning came up on my radio screen to start the engine or it would turn completely off to save the battery. I believe it was referring to the 12v battery. If there is another way to keep the radio on, I'm not sure how to do that. After I started the engine, it did start as needed and stop when charged until the next start. Probably 15 min intervals. I didn't mind leaving the truck to run when it needed, but the drive in doesn't want people idling their vehicles.

 

[Tbone289]

Stardate 41153.7 -
Mission complete.
The Bed Plug Incident:
Truck turned on / off with no load on bed plugs= No power to plugs after shutoff.
Minimal load (12 volt test light) on power plug with ignition on.
Power remains on after ignition is off.
Vehicle performing as designed.
Issue terminated.

Same Stardate, Different Maverick (2024 Ecoboost)
Ignition on/off with no load on any 12V accessory circuit = 12V accessory power available
Tested by successfully powering on custom bed lights via mechanical switch after ignition turned off and key removed
Vehicle performing as designed and preferred by owner
Test complete

Now I'm curious if this is a model year change in the logic, a Hybrid/EB difference in the logic, or a combination of the two.

 

[MaverickDragon]

@Tbone289 - Hard to say except that there are differences, and like you said it's EB vs, Hybrid and 24 vs 25. One too many variables...

It does explain why different people reported different results - There are differences, at least that's been proven between the two if us. Whether that's due to software versions or powertrain.. IDK.

My best guess is it was a part of the quest to save the 12 volt battery... but that's just conjecture on my part.

The good news is we are both happy with our trucks.

 

[Tbone289]

@Tbone289 - Hard to say except that there are differences, and like you said it's EB vs, Hybrid and 24 vs 25. One too many variables...

It does explain why different people reported different results - There are differences, at least that's been proven between the two if us. Whether that's due to software versions or powertrain.. IDK.

My best guess is it was a part of the quest to save the 12 volt battery... but that's just conjecture on my part.

The good news is we are both happy with our trucks.

I concur on the change likely being to help save the battery, and it's good to know Ford was being proactive on that front. I suspect that it's a model year related vs. powertrain, as I believe the BCM and coding are shared between EB and Hybrid.

Though I prefer how mine operates, it's also good to know there is an easy solution for that operation if I owned one like yours by simply plugging in a minor load. Either way it's not a deal breaker.

 

[SafetyGuy]

I believe when I got to where I was parking, I kept my foot on the brake, put it in park and turned the key to power accessories. It turned the gas motor off. It was about 5 to 10 min that the warning came up on my radio screen to start the engine or it would turn completely off to save the battery. I believe it was referring to the 12v battery. If there is another way to keep the radio on, I'm not sure how to do that. After I started the engine, it did start as needed and stop when charged until the next start. Probably 15 min intervals. I didn't mind leaving the truck to run when it needed, but the drive in doesn't want people idling their vehicles.

Good day

It looks like I will have to do a bit of research on how a hybrid truck with an ignition switch works, to figure out how you can use the engine cycling of and on as needed to support your High Voltage battery.

I do believe you were just using your 12 volt battery but I am not an expert...it just sounds like it as the engine did not cycle on its own.

MTF, once I have time to try and figure this out...

Andy

 

[SafetyGuy]

Good day

Okay, I just finished several hours of messing with the truck in the garage...gotta like it!

All in trying to see if 12 volt power is or isn't present if no loads plugged i to the 12 volt ports.

I have used my truck, a 2025 Lariat hybrid that has had all updates that are available for it as the test vehicle, and has a battery that was almost fully charged before beginning.

It has no electrical, battery etc issues that I know of other then the need for using MM's lights tricks to keep the battery topped up.

I used my Klein clamp meter (the clamp portion of it) for the first time (read the manual on operation, again) to read the amperage.

The panel in the back left corner of the box that holds the 120 volt plug was removed for access.

Power applied to 12 volt system

This is after the truck timed out and all 12 volt power was lost.

I clamped/metered the wire leading to the 12 volt power port, turned on and off accessory power and with all 12 volt loads removed prior, the 12 volt port was powered, with nothing plugged in, in the truck. I had to use the DC amperage setting.

When the truck timed out after about 90 minutes, all power was lost in the 12 volt system, as expected and as indicated.

Every trucks operation may vary, and battery charge status will affect operation as well.

Andy

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