System Off to Save Battery message

[GDN]

WTH Ford you're stressing me out. What do you want me to do? Turn it off ? Or Turn it on? Or Off? Or On? You've not leaving me many options !

Haven't driven the truck for 4 days. Anytime it sits for at least 2 days I know the systems will be totally shut down and I always get the default sounds and dings.

I don't recall this message though. After my short drive and I was turning the truck off to get out. I had hit the Off switch but not opened the door. So I'm guessing was in accessory mode for 10 minutes or whatever the countdown timer is. To say the least Ford wants me to take action - Turn it off or Turn it On. WTH - Ford you do the right thing - it doesn't matter what I choose - you start a 12v charge cycle in the background if you haven't already. Just do your job and take care of the electrical system. No need to ask me or any other driver or display your stupidity on screen for all to see. Just do your job and manage the electrical systems.

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[MountainAlive]

You gotta switch to decaf, man. But I agree it’s odd how Ford lets the 12v get so low when it can simply recharge it at anytime from the high voltage pack. It’s not like an ICE vehicle where you have to drive it to recharge the 12v.

 

[Maquis]

There shouldn’t even be an “Accessory” mode. On or off…end of story. Then all this goes away.

 

[Heliian]

you have to drive it to recharge the 12v.

shouldn’t even be an “Accessory” mode.

It's a way to power the vehicle without powering the motors.
Simple, yet effective.

 

[Maquis]

It's a way to power the vehicle without powering the motors.
Simple, yet effective.

The motors aren’t powered until you put it in gear. The only thing accomplished by accessory mode is that it allows you use the 12V battery without the normal capability to charge it. EVs made by non-legacy auto manufacturers don’t do this.

 

[Henry Ford]

Maybe you just have a bad battery. I never get battery related messages and my truck frequently sits for days. My wife's Navigator frequently displayed battery related messages until the battery was replaced. It took a couple trips to the dealership to convince them there was a problem but the new battery fixed what a software update didn't.

 

[Adventureboy]

The motors aren’t powered until you put it in gear. The only thing accomplished by accessory mode is that it allows you use the 12V battery without the normal capability to charge it. EVs made by non-legacy auto manufacturers don’t do this.

Actually the DC to DC charger kicks in now in Accessory mode. I have a 2023 and initially it didn't, but Ford fixed it and now turns on the charger. Still, there is little point to the Accessory only mode.

FWIW, @Ford Motor Company does need to fix the 12v drain issue. Even while plugged in, the truck drains the 12v battery to ridiculous levels, when the EVSE power is RIGHT THERE and plugged in. The truck will eventually charge it from the HVB but only after it shuts everything down. Why not just maintain it, especially if it is plugged in? Even if not plugged in, the truck should maintain the 12v battery above 50% SOC for a couple of weeks before shutting things down provided the HVB SOC is above a certain level (say 20%)

It should be an easy fix.

 

[GDN]

Actually the DC to DC charger kicks in now in Accessory mode. I have a 2023 and initially it didn't, but Ford fixed it and now turns on the charger. Still, there is little point to the Accessory only mode.

FWIW, @Ford Motor Company does need to fix the 12v drain issue. Even while plugged in, the truck drains the 12v battery to ridiculous levels, when the EVSE power is RIGHT THERE and plugged in. The truck will eventually charge it from the HVB but only after it shuts everything down. Why not just maintain it, especially if it is plugged in? Even if not plugged in, the truck should maintain the 12v battery above 50% SOC for a couple of weeks before shutting things down provided the HVB SOC is above a certain level (say 20%)

It should be an easy fix.

You nailed it. I find it ironic that Ford owners want to brag about no "phantom drain". Sadly all this means is that Ford isn't maintaining the 12v battery and we have nothing like Sentry mode, which I think every owner on this forum has asked about our expressed an interest in at one time or another.

Tesla had early problems with phantom drain, but they have that fixed now. So when you hear a Tesla owner note it or complain about it - truly its just part of having an EV, you know it is taking care of itself.

 

[WhiteBolt]

I thought the recent BCM update took care of 12v battery issues?
ECG-25.2.5.7.1
"This update refines the Gateway Module to prevent drainage of the 12V battery."

 

[Maquis]

I thought the recent BCM update took care of 12v battery issues?
ECG-25.2.5.7.1
"This update refines the Gateway Module to prevent drainage of the 12V battery."

The OP had his truck in accessory mode. That uses the 12V battery and won’t charge it. Just don’t use accessory mode - turn the truck on if you need to do anything with it.

 

[GDN]

I thought the recent BCM update took care of 12v battery issues?
ECG-25.2.5.7.1
"This update refines the Gateway Module to prevent drainage of the 12V battery."

Nothing Ford has done has fixed the 12 v issue. They say they continue to tweak it. I've got all of the pushed updated except BC 1.4. I've the latest for the GW and other modules to help regulate 12v. Still I didn't drive for 4 days this past week, got in the truck and once again power issues. The truck has resorted the old standard dings and needed to run a charge cycle for the 12v battery. Sitting for 4 days shouldn't get the truck to that situation.

 

[Kansan]

There shouldn’t even be an “Accessory” mode. On or off…end of story. Then all this goes away.

My 24 Flash charges the 12V system while in accessory mode.

 

[GDN]

My 24 Flash charges the 12V system while in accessory mode.

Accessory mode should have nothing to do with it. What about the other 18 to 20 or sometimes 24 hours a day it sits. Shouldn't Ford be maintaining the 12v battery?

 

[Scorpio3d]

As far as “accessory mode“ goes with the Ford vehicles, it is for programming for the service techs. When programming the vehicle many(most)times you have to do it key on engine off! With push button ignition, you don’t really have that. In older vehicles with keyed ignitions you did have that. ICE push button ignitions do exactly the same thing as the Lightning.

 

[Kansan]

Accessory mode should have nothing to do with it. What about the other 18 to 20 or sometimes 24 hours a day it sits. Shouldn't Ford be maintaining the 12v battery?

I was just replying with real data to a comment. No need to hate on accessory mode - it charges the 12V. I agree with an earlier comment though - not sure why Ford even kept the accessory mode on the BEV - other than the fact that the modules are very similar to the ICE trucks. (Another similarity is that remote start from a key fob works even though we don’t get key fobs with that button).

The real problem is that the 12V battery is too small and the fact that the modules take nearly a half hour to shut down after ignition off. In my Lightning I upgraded to an H3 battery with about 15% more capacity and it’s a nice improvement. If I get the nerve to modify the battery tray I’ll put in a bigger battery next time - maybe H6 size.

Many of the modules in our trucks behave just like their ICE brethren. I’d bet money that the Lightning 12V BMS can adapt to a much bigger battery just like the ICE BMS. Ford has the same problem with the 12V batteries in the ICE trucks. The forums are filled with threads about battery saver mode and the need to increase the size of the battery. In my 23 5.0 Lariat I replaced the factory H6 with an H8 sized battery and it’s a huge improvement. BMS easily adapted to the bigger capacity and I never get battery saver mode any more.

I will agree too that the 12V BMS should be set up so that the HVB tops off the LVB at a much higher minimum voltage set point.

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