Low 12v Battery Message

[TheArborist]

Snakebitten, did you get your service manual direct from Ford?

I've been fighting voltage issues myself.. stranded twice, no low voltage alarms just won't start and a pop-up saying "Stop safely now". -ye, thanks tips..

First time it happened: working late in -41'C, two consecutive command starts with no problem then knew I had to go manually start the truck. Would not start. No alarms other than the pop up mentioned above. Tested battery at 11.8V. Tried to jump start, no go. Tried battery charger at 15A, voltage up to 14.3V over half an hour but still no start. Left charger on for a couple of hours, still wouldn't start. Tried manual BMS reset few times (flash brights x5, brakes x3). Disconnected everything to head home with spare work truck but decided to try command start on the way out and it started! Wtf..

Took truck to local dealership, no codes other than low voltage. Battery tested fine. Charged for hour at the dealership, reset BMS and went home. No issues for three days.

Christmas Eve truck is dead again (-23'C.. warmer than previous week). All of the same issues. Tried Noco GB70 to jump start, no luck, just clicking away.. back to charger, messed around for hours but still no luck. Took aux 12V out and threw it on the Noco Genius for a proper charge overnight. Put aux battery back under the seat Christmas morning but still no starting.. was ready to start the thing on fire but had to visit family. Next morning, command start worked first try.

Also worth noting, not once has the truck gone into deep sleep. Every time I tried to start the truck manually all lights and radio and fan would come on until I turned the power off to each. Even a pop-up on the cluster say "Full accessory power active".

Now I'm just left wondering how to prevent this going forward! The truck has run fine all week but the weather has warmed up significantly, been -10'C to -20'C.

I work remotely often.. I'm really nervous knowing the Noco jump starter doesn't work to get these trucks going.

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[Snakebitten]

Are you a Powerboost?

 

[TheArborist]

Yessir, 2022 Powerboost.

Just hit 2400 kms. Frustrated to have these issues already

 

[Calson]

Not just cold weather as I had the problem last week with my truck and the lowest the temperature during the week was 48 degrees.

 

[scott011422]

So I went outside today after sitting 18hrs. Temps between 32 and 40 for the last 24h. Went to dinner last night 40min away. Got home about 8pm and has sat. Battery voltage reads 11.99 to 12.01. Went to put my NOCO Genius G3500 on it and the charger only sees it as a small normal battery. Forced it to a large AGM and its charging. Currently working on charging it to 25%.

 

[jeffrt]

So I went outside today after sitting 18hrs. Temps between 32 and 40 for the last 24h. Went to dinner last night 40min away. Got home about 8pm and has sat. Battery voltage reads 11.99 to 12.01. Went to put my NOCO Genius G3500 on it and the charger only sees it as a small normal battery. Forced it to a large AGM and its charging. Currently working on charging it to 25%.

Curious to see what you can get it up to. My battery died on me the other day, and charged it all day yesterday with the same charger. Charger showed 100%, but I’m only seeing 12.1V with a meter. Went for a drive today, and still only seeing 12.1V. Still planning on calling the dealer next week to see what they say.

 

[scott011422]

So oddly enough it only took 2 hours at 3.5 max amps to charge the battery. Letting it settle 5min (4:05pm), battery was 12.91. 80ish min later it was 12.62. 11am this morning, 11.91.

I have no errands to do today so im doing this again with the battery disconnected, Just to make 100% sure its the battery.

I'll either replace it with an Interstate MTX-94R/H7, or an Odyssey ODP-AGM94R H7 L4 .

 

[scott011422]

Looking very much like it could be the truck. I charged with the negative lead disconnected. Again, took about 2 hours with a 3.5a charger to finish. Unfortunately I squirreled and didn't check the battery for 15min which was 12.78v. 80min later it was 12.63 and this morning it was 12,59. Not as good as id like to see a less than a year old battery, But 90% is much better than 30ish %.

More interesting was that the battery leads had power after i disconnected them. They had 12.7 when I checked at the 15 min check. They were 11.48 this morning. This could only be the small battery under the back seat. What is interesting is Ford says that battery is only connected when it needs it for cranking. Obviously that's not true. And if that little battery was keeping the truck alive for 18ish hours, 11.5 could be about right? I'm not sure what the truck pulls when its parked but that battery isn't very large.

I also don't have 100% faith in my charger. The battery charge gauge hasn't worked correct in over a year. While it did bring the battery to near full charge, I'm not 100% sure it was 100%. Each % it is working on is to be flashing with previously completed % to be solid. When charging is complete, the Green 100% light should be on and steady with all previous % leds off. This never happens anymore. 25,50 and 75 stay on steady with no 100 forever. Days later will still show the same. Every battery for as long as its connected. The odd thing is my Father has a G3500 and a G1500 and they both started doing the same after about a year old. Still seem to work fine otherwise.

Just cant be certain the charge ever finished.

 

[Snakebitten]

Snip

What is interesting is Ford says that battery is only connected when it needs it for cranking. Obviously that's not true.

I'm not sure that's what Ford says.

My understanding (and it could be wrong) is that the small battery is ALWAYS in use, but is "isolated" from the underhood battery during starter cranking event.

Or put another way, during a high Amp draw (starter cranking event), the underhood battery gets isolated from everything on the 12V system except what's necessary to turn the ICE over. So for those moments the 12V array of components in the truck are temporarily being supported by the small battery only.

Once the high amperage event is over, the isolator is opened and the two batteries return to their normal state of sharing the load in parallel.

All of this is my understanding of my Powerboost. But it's been an ongoing learning experience and I have been confused more than a few times.

 

[scott011422]

That's interesting. And with the way they worded it, Totally possible.

I wonder if that's why the smart charger gets confused on the size and type of battery its connected to. At the same time, If you were to hook the charger up to the battery leads with the main battery disconnected, Would it recognize the small battery?

 

[Snakebitten]

I would be surprised if you didn't see 12V (the auxiliary battery) across the battery terminals that are disconnected from the underhood battery.
Of course I'm not sure how the isolator works either. But documentation states that the isolator is controlled by the PCM.

 

[scott011422]

More interesting was that the battery leads had power after i disconnected them. They had 12.7 when I checked at the 15 min check. They were 11.48 this morning. This could only be the small battery under the back seat. What is interesting is Ford says that battery is only connected when it needs it for cranking. Obviously that's not true. And if that little battery was keeping the truck alive for 18ish hours, 11.5 could be about right? I'm not sure what the truck pulls when its parked but that battery isn't very large.

I did! lol!

 

[scott011422]

Im questioning the battery again too. Looks like it should have taken 20 to 30 hours to charge that battery from 50% to 100% at 2 amps.

It took my 3.5 amp charger less than 2 hours to go from 40% to 100% That battery doesn't seem to be taking many amps. Going to grab a resistive battery checker tomorrow and put the battery under a load.

 

[Ericcc]

My 2022 could not start on 12/30/2022. I hooked it up to a jump starter. Then the truck started to click and lights started to blick. The car screen started and failed, then started and failed, then started and failed.
I had to remove the positive plug away from the car battery and connected the cositive plug directly to the jump starter. Without the car battery, I sucessfully started the car. Then I connected the positive plug back to the car battery.

 

[Ericcc]

Im questioning the battery again too. Looks like it should have taken 20 to 30 hours to charge that battery from 50% to 100% at 2 amps.

It took my 3.5 amp charger less than 2 hours to go from 40% to 100% That battery doesn't seem to be taking many amps. Going to grab a resistive battery checker tomorrow and put the battery under a load.

I watched a video which says the car keeps pulling 18 AMP from the battery just sitting there. There are so many systems in the car. Here is the video.
Ford BMS Battery Monitoring System: How it Works and How to Properly Charge Your Battery!

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