You will be fine charging with the supplied wallwart charger. But get an expanded scale voltmeter that simulates servo load and test before flying. I use an Expert brand LED tester that loads the battery. I use this before I fly for the 1st time and after every flight. When the LED lights get halfway down between the amber between the red and green I top up with the field charger. I make it a regular habit of cycling my batteries once about every 3 trips to the field. Always test them before you fly to make sure that they didn't false peak.

Curt