This spring system was really bad, I cleened it carefully, but when I shake the transmitter or rotate some cells,
the TX battery powermeter showed BAD connections !!
I removed all the springs and metal stuff, except for the final plus and minus terminals.
The NiMH cells are covered by a thin metal layer that is impossible to solder on,
so carefully remove it using sandpaper or a sharp screwdriver or what ever you have.
SOLDERING: it is important to use a HOT soldering iron and SUPER short soldering time (0.5 SEC)
If you solder 1-2 SEC you will permanently damage the cells !!
See how nice this is.. now it is impossible to have loose connections..
Placing a little fuse in series with the battery can be a good idea,
remember the battery can easy melt and burn wires if you short circuit some thing.
I have also soldered directly on my 4 cell reciever pack, it would be TOO BAD if I crash due to bad connections.