I dunno, Tom ... sounds a little like Li-Time was just trying to sell you a charger. My buddy and I have 12v NOCO chargers on our boats, and they will charge Lead Acid, AGM, and Lithium batteries at the same time. You just have to set each lead to the type of battery it's hooked up to.

I basically fell for the same deal when I bought my Eco-Worthy 50ah battery. I bought the charger, but I did not have a smart charger at the time. I used the EW 50ah battery to run my Livescope & 93sv unit and it lasted 6hrs before shutting off. I realized shortly thereafter that I had not charged the battery to full capacity. It was probably charged at somewhere around 75% & I was just reading the battery charger wrong. I really only expected the battery to run my setup for about 8hrs, as that's usually my avg. time fishing. I was calculating around a 5amp draw from the setup for 8hrs continuous pull (8x5=40) which would leave me 10ah overage for insurance.
I still don't know if it'll last that long, because I have a series 24 lead acid battery for the LS setup, and just carry the lithium 50ah battery as a backup.

The Eco-Worthy charger is a one lead 12V smart charger ... so it, too, could be used to charge LA, AGM, or Lithium batteries.

I've also noticed that since using a "smart charger", my batteries stay fully charged longer (when not in use) than they did back when I was charging them with the MK220.