Here you can find the Eclipson standard batteries.
The battery provides you the energy to fly your model but also is the main ballast to set the CG in the right place.
Have a look the "shopping list" section to know which is the proposed battery size for your Eclipson model.
CAPACITY- 500 mah
VOLTAGE - 7,4 (2S)
WEIGHT - 35 gr
CAPACITY- 1500 mah
VOLTAGE - 11,1 (3S)
WEIGHT - 120 gr