I started with a small quadrocopter to learn to deal with the thing.
The first problem it flies only 4-6 minutes with a charged battery. So I had to buy a few more. Now I have the problem lying around and at the loading they also take their place.
With this battery holder all batteries are in place and for charging they are in a fixed place.
The holder is for model batteries of the type: 3.7V 800mA (55mm x 25mm x 8mm).
Quite simply but for that I do not have to search any battere anymore. ;)