I meant what charger are you using as there are very few chargers out there that will manage lithium batteries properly and your alternator wont do it without something else to manage the various stages of charge you need for a LiPo battery.
I want to fit two lithium batteries, I have a solar charger that fits the bill but have yet to sort out alternator and mains chargers.
As yet I have not had a issue, when I go on a club site, mains hook up, its showing a 10 amp charge to the batteries, when they are fully charged, it drops to about 1.5 amps automatically. On the display panel it shows approx. 13.9 to 14.1 volts when charging at 10amps, drops to 13.3 volts, when fully charged, they've held 13.3volts since our last trip 10 days ago. That's as much as I can tell you at the moment.
When I first purchased the batteries, I also bought a smart charger. a NOCO GENIUS Battery charger G26000 12V/24V 26amp.