Better charge it at 1C.(5A) To charge at 14.8v(4s) Lipo you need a Battery charger with min 75W of port power. Normally are with 50w - 50w/14.8=3,37A (66-70 min charging time), you cant charge at 2c without a better lipocharger and power supply.
WHEN YOU FIRST TRY ONE OF THESE YOU WILL DEFINITELY SEE THE DIFFERENCE. I WAS USING THE 5000MAH ZIPPYS, AND THEY STARTED TO SWELL UP. AND I NEVER EVEN OVERHEATED OR DREW THEM DOWN TO HALF THEIR VOLTAGE RATING,,, NOW, I HAVE SOME REAL POWER WITH THESE NEW TURNIGY BATTERIES! I USE THEM IN MY HANGER 9 POWERED WITH AN E-FLITE POWER NINETY, AND THESE NEW BATTERIES WILL TAKE IT STRAIGHT UP AFTER TAKE OFF AND JUST KEEP ON GOING! IT OUTRUNS MY 60 SIZE HANGER 9 COSAIR WITH A SAITO 100! TALK ABOUT POWER, AND THESE BATTERIES DON'T SWELL UP LIKE THE ZIPPYS DID. NOW I CAN FLY WITH FULL POWER LONGER AND DON'T HAVE TO WORRY ABOUT LOSING POWER DUE TO OVERHEATED BATTERIES!