The JG/ECHO 1 series comes with a 1100mah NiMh battery if I am not mistaken. If you charge it fully and leave it around for 10 days, it should have self discharged itself. In combat, your battery should last a little over 1000 rounds.
As for charging, look at the charger. Normally, the cheap package chargers are about 350 mah. Thats how many Mah it puts in the battery each hour. so if your charger is 100 Mah and battery 600, then you would charge it for 6 hours. If the charger is 350 mah, and the battery is 1100, 1100/350=3.14 hours.
But if it gets hot, take it off. Heat is bad, especially for NiMh batteries.
Woah, the 2 previos posts went up while I was writing.
Lulz and Rolls