what agm charger yall use?

[devin171moto]

I tune and charge using one of these.......been goin strong 5 years now, can tune for hours full volume

https://www.amazon.com/dp/B01H0QTS18/?tag=caraudiocom-20

thanks for this suggestion. most likely going with this

 

[some dude]

I'm trying to learn about AGM batteries. What is the basic deal on running one in my car and having the alternator keep it charged? From what I've read people use them as 'regular' batteries.
When does charging with a charger come in to play? Is it required regardless of how you use it? Sorry if off topic I'm just confused and trying to learn.