Kind of stumped on this one. Truck is less than a year old and I seem to have battery issues but I’ve never had a battery issue present in this way.

a few months ago I noted a really weak start when I went camping. The battery was clearly weak, and I put it down to being 50°, and me going in and out of the truck while I was unloading my tent etc.

Fast forward a month. No issues. Strong starts, even two days ago I had started the car to go down to the grocery store. Zero issues.

This morning, I go out, it’s 58° (we apparently hit 46° overnight), press the start button and the engine hardly cranks, ignition clocks like crazy, and she’s dead.

So, flat battery. Right?

I press again and it turns the engine really slowly once or twice, then clicks repeatedly and dies again.

I tried again and the engine turned once normally but not enough to start then died. Then once more it barely turned and then it died.

Then one more try and the whole thing just starts completely normally like nothing ever happened.

It’s like the battery got stronger... as I was cranking. By rights it shouldn’t have even cranked after the first go since that would have drained the residual charge.

So this makes me wonder if it’s actually the battery, or whether something in the engine itself, that the turning over somehow “freed” something up - however the noises were all characteristic of an incredibly weak battery, right up until they weren’t. Only other thing I can think of is a bad cell on the battery.

Oh, and the battery was allegedly replaced when I bought the truck, because it was flat then before the rest drive (which I put down to just being sat on the lot and I thought “ok. Fair enough, 2019 truck that’s been made and sat there for six months or so. Clearly that was a mistake). But yeah, I’ve never heard of a dead battery magically come back to life like this

edit: battery has sticker indicating it was built 01/20 - I bought the truck in February. So it’s conceivable they did in fact replace the battery which means I have a vampire draw if it is the battery - only thing added is the dashcam which definitively turns off when the ignition is off

 

My first reaction to this is you may have a loose ground issue not necessarily being the battery ground cable but, a body ground. Simply check for loose connections, including the starter connections, there are an inordinate amount of connections to the starter on these trucks. Load test the battery after a full charge. Since it is a newer battery than original, it should check out OK and you can eliminate the battery from the issue. Another thing may be a battery drain issue but, you describe an intermittent issue in the last part of your post which is why I suggested a loose connection somewhere. So, in summary, check for loose connections, load test the battery and then, check for drainage.

 

Could be that the truck turned off all of the accessories and it had enough to get it turned over then. Ours did that.

We just had our 2020 (delivered one day before we picked it up in March) battery replaced. We drove it for 30-mins twice a week during the lock down and it has
been driven enough that the battery should have been charged. Even charged it 3 ties to make sure. There is a back order on the batteries(so maybe they had a bad
batch?) so they got an O Reilly battery and installed it. They will put in a OEM when they get one, but at least I have something that works now.

Have you checked the voltage of the better to see the charge level?(close to 12.6?) Have you put it on a charger to charge it?(make sure it is really charged?) Have
you monitored the voltage while driving to see if the truck "feels" it is charged? (Drop to around 13.8 float level?) These can eliminate the battery

 

It's a bad battery. You've dropped a cell, which means high internal resistance, which means big loads will generate heat. Your battery is sorta getting "stronger" because the chemical reaction is better when things are warm. Drop a quality AGM in there (I've not had great luck with MC batteries, personally) and see if things improve.

 

Two batteries in two years? Something else is up.

 

If anyone cares, it looks like Costco/Interstate started doing AGM batteries for the truck.

On this one, it does seem like it's maybe a bad cell, you're going to have to do a little battery basics, what is the voltage? what does a real battery charger think of it's current state? (not a jump pack)

 

Less than a year old,.................let the dealership figure it out..
.

 

I'm going through this, but with the wife's '18 expy with the 3.5L. Gave it to the dealership to figure out this morning. My assumption is a bad battery. the part I'm concerned with is the battery in there is not a factory AMG Motorcraft battery, but a CarQuest AMG. Which suggests to me that there is something else going on. We technically bought it "used" with 283 miles on it June of this year and now has 7,500 miles. But still has the bumper to bumper warranty...so we'll see what comes of it.

I checked voltage when on, after a long drive, and after sitting in the garage for the night (~10 hrs). What I saw was 14.3V when on (i.e. charging the battery), 12.9V after a long drive, and 12.1V after sitting for the night. I don't have the ability to do a stress test on the battery, but my assumption is a bad battery. Just odd based on the mileage, age, etc that it's on (presumably) the 2nd battery.

 

As one person mentioned “less than a year old, let the dealer handle it”

I did check the battery going in, 14.4 v while engine running, 12.7v idle. I brought it up with the dealer and they agreed it sounded odd.

battery failed a load test and was replaced, strangely with a ‘super start’ rather than motor craft. It’s November, but the sticker on the battery says 12/20. My old battery said 01/20 - I bought the car in February, and I assumed I got a battery manufactured in January, however, I now wonder if they ever replaced the battery when I bought it like they said they did as the sticker date could indicate that it was replaced in December (and got a January sticker)

Dealer did agree it was weird and wanted to start with the battery, but would move on to alternator, earths and others afterwards.

He started by just saying about the battery but the moment I mentioned had recordings, was much more willing to listen.

Could just be the dealer that sold me the car never changed the battery like they said they did, could be something else. Weird that they didn’t give me a motorcraft battery, even weirder hearing hickmanfab is going through a very similar issue. I’d be interested to see how yours progresses. I’ll use this thread for any further documentation

 

That is completely normal. Welcome to the Battery Management System.