LOW 12V BATTERY

[gadiedrick]

We've been drive'n our Powerboost for the last 6 weeks. When the vehicle is garaged @ the end of the day I sometimes leave the key FOB lay'n in the console. The next day when we go to start it & open the door of the vehicle the interior courtesy lites do not turn on & then when we start the vehicle we get a display prompt on the dash indicating LOW 12V BATTERY. It does not seem to be an issue if we remember to take the key FOB outta the vehicle. Do we have a bad battery or is the problem us?

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[John_C]

On most keyless push to start vehicles, the presence of the key will keep the vehicle from "going to sleep" because it thinks you're about to use it. Not sure if the F150 is the same or not.

 

[Kefoster2]

We've been drive'n our Powerboost for the last 6 weeks. When the vehicle is garaged @ the end of the day I sometimes leave the key FOB lay'n in the console. The next day when we go to start it & open the door of the vehicle the interior courtesy lites do not turn on & then when we start the vehicle we get a display prompt on the dash indicating LOW 12V BATTERY. It does not seem to be an issue if we remember to take the key FOB outta the vehicle. Do we have a bad battery or is the problem us?

I think the OTA update just pushed for the zone lighting and battery drain issue has fixed this. I noticed when I shut truck down last night and today I had a warning message that the power system was shutting down totally to preserve the battery. However this morning when I fired it up I got a low 12v battery message. I will see if it happens again tomorrow.

 

[MXA]

I think the OTA update just pushed for the zone lighting and battery drain issue has fixed this. I noticed when I shut truck down last night and today I had a warning message that the power system was shutting down totally to preserve the battery. However this morning when I fired it up I got a low 12v battery message. I will see if it happens again tomorrow.

I am sure it has been posted previously but there is a known battery leak. My 150 powerboost had it, this required 3 days in shop last week to update the software (dealer said it took them multiple tries). The truck basically was dead electronically. I jumped it to get it to the dealer with no problems. It seems the hybrid battery is completely separate from 12V.

Slightly funny that I could probably jump start the 12V with my hybrid battery .... Cheers.

 

[discothan]

Slightly funny that I could probably jump start the 12V with my hybrid battery .... Cheers.

Majority of drivable RVs that have both house batteries and engine batteries have this functionality. Flip a switch and you can start the engine with the house batteries.

 

[imnuts]

The hybrid battery is 48VDC from what I've seen, and probably isn't designed for the load of a starter, especially when going through a DC-DC transformer. I could see it providing accessory power, but not starting the truck.

 

[Slappy McGee]

Slightly funny that I could probably jump start the 12V with my hybrid battery .... Cheers.

I registered and am replying solely in the hopes of saving some poor sod some 12V heartbreak. I have a Powerboost on order but this is my 4th hybrid or electric vehicle, and in all my previous 3, the 12V battery essentially acts as the "gateway" to access the larger "drive" battery. I don't know the engineering details, but I believe this allows the manufacturer to use standard 12V electronics (vs. drive batteries that run at 48V), and also allows for a measure of safety since the 12V side does a "systems check" before throwing the "big switch" to connect the drive battery into the system.

This is all well and good, but where problems arise, is that in both my pure electric car (Chevy Bolt, friend's Tesla) and hybrid (Chrysler Pacifica) when the 12V dies you can't start the car. Again not a huge problem except that in all 3 cases the car won't attempt to turn over, and you get all manner of crazy error messages about powertrain failures, "get service immediately," world is ending, etc., with nary a message related to the 12V being dead.

The first time this happened in our Pacifica we were 1000 miles from home over Christmas and got a flatbed to a dealer, and waited 3 days to find out we just needed a new 12V battery I could have changed myself in an hour. When it happened to my Bolt, I used a jumper pack and was able to start and drive it to the dealer for a warranty replacement of the 12V. Super simple but again all the error messages were related to drivetrain failures rather than "Please replace the 12V you big bozo" which would have been way more helpful.

Perhaps Ford is smarter than Tesla, GM, and FCA, but to make a short story long, if your powerboost won't start and gives all kinds of crazy error messages try giving it a jump and it might just be a simple battery replacement that rights the ship. It still blows my mind when you consider your vehicle contains a gigantic battery but can't access it without the lowly 12V battery functioning, and it's not smart enough to tell you that.

 

[gadiedrick]

After having to jump start our '21 F150 shortly after delivery we continued to get an occasional notice of LOW 12 VOLT BATTERY. Thanks to this forum I contacted our dealer & asked if Technical Service Bulletin (TSB) 21-2097 was a possible fix to our problem. It took a couple hours @ the dealership to access the onboard computer/confuser & revise the SLEEP MODE per the TSB & correct the problem. Thank you f150gen14 forum!

 

[Hamboni]

Good info in this thread, I'll be sure to keep it in mind when mine arrives!

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