Hi!
....Are you guys still using NiCad:s??? Over here in Sweden , and the rest of Europe there is no Nicad batteries to be seen anywhere. I use NiMh cells and that is what's inside every radio over here.

I have been flying for more than 30 years and have always soldered my own battery packs! I use a 50W "Weller" soldering iron , and I have had no trouble soldering both transmitter packs and reciever packs.
The secret to soldering Nicad and NiMH batteries is speed and to pre clean the surface that is to be soldered (which means using fine sandpaper to roughen up the surface on the battery and then solder a thin layer of tin onto the surface).

I mostly use 1800 mAh-2800 mAh NiMH batteries (R6 or AA size)in my bigger airplanes and 1000mAh NiMH batteries (half the weight and size of R6) in my Q-500 pylonracers.
I use a 50-100mAh JR wall charger for my battery packs.

No plastic battery holder should be used in an airplane because of a possible bad contact. Always sweat solder together batteries!