Cold weather and battery performance, AGM batteries

Have the batteries tested, individually. If one is bad, replace ALL of them at the same time.

 

get yourself one of those USB phone chargers that plugs into the power outlet and has a digital voltage display and start watching the alternator voltage while the engine is running and the resting battery voltage while it’s off. They’re like $15 on Amazon.

You could have a charging system issue, tired batteries, or a draw somewhere that needs fixed. AGM doesn’t typically cause any problems even if the vehicle didn’t originally come with them. (Switching back to flooded batteries on a vehicle that originally came with AGM I’ve been told is a no-no). On a practically new truck I would be a little surprised they’d be bad already unless something else was going on.

 

why replacing all of them if one is bad?! , I had good experience replacing just 1 or 2 .

 

I've had better reliability changing the whole set - and if they've been bad for a while, replacing the alternator too.

 

I’ve never been a fan of AGM batteries in cold weather.

 

https://www.amazon.com/dp/B085LKLCY...p_csd=d2lkZ2V0TmFtZT1zcF9kZXRhaWxfdGhlbWF0aWM

That one looks pretty good.

 

I would be careful about throwing any parts at all at this one until its had some diagnostics done on the charging system.

 

If your truck can't sit for a 34 then there is something wrong with the charging system or a big drain on your batteries. I run agm's because I spend to much time up north and they are the only thing that works when it is -20 out. I did have to go through my dash and remove an old eld system that was in my truck draining the batteries though, now I can let it sit for a week and the batteries are fine

 

My bet is he has a parasitic draw somewhere from some aftermarket Monkeying around with the electrical system. Not super likely his batteries or alternator just randomly went bad on a truck that new. (Not *impossible* of course , but not that likely). That’s why it would be interesting to watch the resting battery voltage with one of those plug in charger outlets. There are also some parasitic draw tests that can be conducted using a multi-meter but that requires some knowledge about how the electrical system works on that type of truck for the readings to mean anything. All modern vehicles will have SOME parasitic draw on the batteries while parked, unless you have a disconnect switch to cut power to the truck. But you’d have to know what a normal amount vs a “not normal” amount of draw is to properly troubleshoot it.