What bettery shoud I use?

[nanonatron]

hi guys,
I of course use Lipo batteries, but I recently heard about Li-ion batteries... so which one is better? I want to do some long range flight, if that helps to form your answer. It also would be very nice if you could tell me what I have to think about. and with Lipos, how do I know what battery to use... so how do I choose the C rating, mAh and so on.
thanks.

 

[FDS]

You need to look at your total amp draw, this is based on motor, prop choice and how hard you are flying. You work out the maximum current drawn by the propulsion system you choose, then allow a 20% headroom. C rating is a function of capacity, its measured at 1000mah or 1ah, so if you have a bigger battery it can put out more current than just the C rating. For example a 2200mah 20C battery can output 20x2.2= 44A approx.
Long flights are down to efficiency, so a larger, slow spinning propellor with a slow spinning motor on a light airframe.
Also bear in mind flying beyond line of sight is illegal in many countries, check your local laws.
As for lipo vs Li ion, pouch cell lipo is capable of much higher overall discharge rates and has lower internal resistance. Li ion is able to output lower currents over slightly longer periods than lipo, it’s sometimes lighter overall than the same capacity lipo pack, but with the lower overall discharge rate.
Some planes can use Li ion to get long flight times but those were efficient designs to begin with.
FT designs specify which battery to use in the plans and on the store listing. If you are building any of those then start with that as a guide.