People keep recommending you get a 6amp or less charger. I dont agree. Get a 10amp or more even. All the newer 5000+ lipo packs can be charged at 10amps easy with no issues. It will take over a hour to charge a 5200 lipo pack at 5-6 amps but at 10 amps it's 35 mins. Your choice though.
Just make sure you do your research on the charging and storage of Lipo's...totally different ball game to nimh