I have a 2020 F-150 XL STX CC 4x4 with the 2.7L. I installed a brand new AGM battery and purchased a battery maintainer (Noco Genius2) because my truck sits for weeks at a time. Hooked up the charger and it seemed to be working great. After a day or so, the battery charge indicator light was all the way to the right and pulsing green (which is the indicator that the battery is fully charged and in maintenance charge mode).

This morning the wife loaded the kids in their car seats and left the doors open for about a minute while loading other stuff. I came out to unhook the charger and noticed that the charging indicator was back down to one pulsing red light (which is the indicator that the battery is under 25% and charging). I was concerned that the truck wasn't going to start but it fired right up.

I then drove us 1 hour and 45 min to our destination, turned the truck off and started it a couple times while running our errands and it started fine. Drove back home 1 hour and 45 min, parked, unloaded and then put the charger back on.

When the charging indicator light came on It again showed that the battery was under 25% and charging (which doesn't make sense because the alternator should have fully charged the battery). Just checked it again about an hour later and it's already up to 50% which seems super fast for a charger of its size.

Does this seem normal and like it's working correctly?

 

Are the lead connections to the charger tight on the clamps? The leads are bolted to the clamps.
Is the lead connector completely latched?
Are you sure you have the charger in AGM mode?
Are you connecting the charger to the battery before connecting to 110 VAC?

 

'Yes' to all of your questions.

 

Not sure if this would cause it but, did you reset the BMS when you installed the new battery?

 

personally...the NOCO is the last charger I would ever use. It doesn't do a true 3 stage charge. It charges up fine but then it turns itself completely off until the battery drops down to a set voltage(possibly 12.5 or 12.6) then charges back up and repeats the process. A true 3 stage charger will put the battery into a float voltage after it does a complete charge...the NOCO does not.

Get a multimeter out and check voltages and see what is actually happening.

 

Yep.

 

Any 3 stage chargers that you recommend?

 

Victron IP65

Hands down, the best portable charger you can buy.

This is the 15A version...they have down to 5A as well


5A version

 

Great, thank you. In the meantime though I need to figure out what's actually going on and if it's something to do with my charger or the battery itself. Anybody else have any feedback?

 

Like I said before, get out your multimeter and check voltages. Check with charger on, charger off and after an amount of time with charger off.