2017 F150 3.5 EB Lariat with auto start stop. The other night, I got a text from my neighbor that lights were on, on my truck. Keyfob was not in the truck, it was inside the house. I was driving a different vehicle, on the way by after dark, I checked the door handle on the truck to make sure it was locked and the lights lit up. I figured he got home right after I did and just saw where they had come on after checking the handle. This is a new vehicle to me so I am not sure all the ins and outs yet.

I verified before I went to bed that there were no lights visible from the front of the vehicle and went to bed. At midnight, I got an alert that the truck went into deep sleep mode.

I was unable to do anything the next morning, after work I brought home an AGM 6 amp 12 volt charger from autozone. The charger quickly went to a flashing green light which means maintenance mode rather than charge mode. I checked the voltage on the battery with a standard multi-meter and it read right at 5 volts.

Two other things to note.
1. There was a small android tablet on the 12v power outlet with a usb charger on it, this never caused a problem in my 2006 F150 with a standard battery. .
2. The auto start stop function was not turning off the previous day which I know is a sign of an issue with a discharged battery.
3. No mods on the truck at all. Stock stereo etc.

I have been told that if an AGM drops below 10 volts it voids the warranty on them (the duracell and X2 batteries specifically) because something ran them completely down and it voids the warranty.

Questions.
1. Would a small android tablet really run down an AGM battery in basically 30 hours. It was on and fully charged when the truck was parked.
2. Wouldn't the truck have a protection circuit in it to keep anything plugged into either the 120 volt outlets or the 12 volt outlets from running the battery completely down?
3. Anything else anyone can think of? I don't want to put a new battery in and then find out that there is something else wrong that ruins a new battery (discharges below 10.5 volts).

No mods on the truck whatsoever, stock everything.

 

Ignore the Android tablet... if *** was disabled the previous day, you had a preexisting condition.
The 120VAC plug is only active when the truck is running. 12VDC plugs stay live.

Any lead-acid chemistry battery (whether flooded or AGM) is typically toast if you deep-discharge it (below 10.5VDC). A quality AGM will usually fare better, but I still wouldn't trust it.

As far as the warranty, as long as you charge it back up (even if it's in bad shape it will almost always hold enough surface charge to read near 12VDC) how are they going to prove it was deep-discharged? I'm not saying you should screw them on the warranty if you screwed up, but...

 

Thanks, I am putting the Duracell 48 month AGM warranty battery on your multiple recommendations in a couple of different threads. Our batteries plus didn't have the X2. We'll see if that resolves the issue. My only other option was the FoMoCo battery. I do not trust hardly any non ford part/battery . . parts market is awful these days.

kw

 

I have seen chargers do that to batteries, when they get that low on charge. If the charger has an engine boost function, put it on engine boost, to get the battery above 10 volts, then switch over to a slow charge.

 

I agree with 20004.6. If your charger has a power supply mode, use it until the battery standing voltage is high enough to use the charger in normal mode. I know you have a different charger but the following may help you out with yours.

The following is from my NOCO smart charger manual

If the battery voltage is below 7.0VDC (12V) or 14.0VDC (24V), the ERROR LED (Orange) and the CHARGE LEDs (25%, 50%, 75%, and 100%) will blink, indicating the battery is out of range for the battery charger. In this situation, the battery charger has determined that the battery voltage is too low to begin a normal charge mode. In order to increase the battery voltage to allow the battery charger to begin charging, follow these steps:

FOR 12V BATTERIES

If you are trying to charge a 12V battery that is below 7.0VDC, you will need to select the 13.6V SUPPLY mode. The 13.6V SUPPLY mode is for 12V batteries ONLY. In this mode, the battery charger does not use battery voltage as a restriction to begin applying current. Before selecting the 13.6V SUPPLY mode, make sure you understand how to use this charge mode by reading “USING 13.6V SUPPLY MODE.”

As a standard matter of practice, allow the battery charger to charge the battery in this mode for at least sixty (60) minutes. After the elapsed time, the battery voltage should be above 7.0VDC. Press the MODE button one (1) time to exit the 13.6V SUPPLY mode and return the battery charger to STANDBY mode. Return the battery charger back to the appropriate 12V charge mode, depending on the chemistry of your battery, to begin the charge cycle.

 

also the 12 DC outlets should get shut down by the BMS when it senses to much battery loss. Even the one that has the battery symbol showing it's powered all the time. There comes a point when the vehicle computer will load shed everything.

I think that might be what happened to you. Now the battery reading 5 volts is a bit worrisome. Makes me wonder if you got a good reading, but it can happen.

Otherwise I often tell people modern cars will cut down a battery in 3-5 years and I bet you're in that margin.

OH what was the tablet plugged into. The USB port with the light up ring around it - or was it plugged into a 12V to USB charger adapter. Which of the 12V power ports was it plugged into It's possible your plug in charger adapter has a problem. Some of them draw significantly off the port even when not used. IE just sitting there without a USB line plugged in - it still draws some current. Which is why I keep mine unplugged.

 

I know on my 2018, the 12V power adapter in the dash will time out after a certain amount of time from factory. I do have the time out feature on mine disabled.

 

Even if you have the time out turned off, will the BMS not still turn it off through load shedding when the voltage drops low enough?

 

Okay, so the AGM battery charger I bought would not charge it because it was too low. Last night I swapped out the battery for the Duracell AGM 94R H7 and everything appeared normal on the truck and it was fine this morning.

I took the FoMoCo battery out, checked the voltage once again with handheld meter. . .4.86 volts and per advice here and elsewhere I put it on a 4 amp conventional charger and checked the voltage every 10-15 minutes or so. Once it was above a 10.5 I put it on my 6amp shchumacher AGM charger. It then went ahead and charged properly. This morning it was at 12.9 volts and 95% charged. I will say the 6 am charger had it at 12.5 in a couple of hours last night. I do think there is something wrong with the battery, I certainly don't trust it in my truck, maybe try and run trolling motor on it next year or backup boat battery. Truck is early 2017 so it has three years on the battery.

Starting did sound different, turning over faster with new battery as well.

To answer your questions, On the USB, it was an Anker 12 volt USB Adapter plugged into the 12 volt outlet on the dash, an already charged Lenovo android device 7" I think. I run Torque Pro on it. It was all configured for the timing issues on the 2006 model and I was just deleting all of those gauges off and putting basic stuff on it and didn't finish. I did connect it to the 2017 and pulled codes(none) It was on but fully charged. The Anker outlet does have a USB C outlet on it but it was not in use, just the 5 volt. I really don't think there was much draw on that. I used to let my 2006 sit for days at a time with it plugged in identically and never had an issue. The android was velcro'd in place on my dash in front of my dash cluster. Had speedometer everything my dash did except turn signals. . . . I was originally tracking a misfire when I set it up that way and then decided I liked it there because I could run waze on it as well. Kinda a poor mans Sync 3. . .

kw

 

Not sure how it happened but it seems as if your battery lost 2 cells (or more) and that's not common but it could happen. Not a typical AGM trait.

Meanwhile the computer should have given indication it was too low or I think it should have. something like a "power saving mode" of the like. I guess your 2017 doesn't have start stop?

regardless new battery is good - I would watch it for a short while. ALso make sure you do the BMS reset procedure.