The 300mAh batteries I had for my Hubsan X4 don't fit. The 240mAh ones do though.
There's no parallel charger for these tiny cells. The best thing is to just get a few of the charge cables. A lot of the places on the bay give you a free charge cable with some batteries so you can charge more than 1 at once.
The 300mah fit if you remove the small plastic tabs in the battery tray? Where's best to sourcetthem from?