I use velcro too. Somtimes wedge or screw down wood tight over the battery, depends on the plane and your battery.

A neat little charge recepatacle is made by MPI http://www.maxxprod.com/mpi/mpi-4.html#5170 Its been new a couple of years now.
The little charge lights work well and for 6v you simply snip in half a jumper wire for 4.8v. Instuctions included with it.

For my trainer I take the rubber bands off after every outing of flight. Mine always get oil on them. They will fail quicker stretched. My 2 cents.
I have a sandwich bag with a 1/4 cup or so baby powder in it. Rubber bands from that day, week, month go in it and I shake it up. Powder soaks up the oil and extends the life a little. At least they are dry even if a bit messy. I guess best would to always use new but....

I use that MPI charge receptacle in most all my planes but the trainer. For it I installed a voltwatch externally under the wing http://www2.towerhobbies.com/cgi-bin...&I=LXMZ56&P=ML, great for heli's too. Cheaper at www.servocity but could only find a picture looking at batteries. For some I use the no light MPI and the voltwatch. It goes neatly under the canopy on the "dash" in a couple of planes.
Its there.

Good Luck
Michael