RE: Battery lead to short
To prevent my battery connectors from disconnecting, I put a piece of heat shrink over them and, then, apply heat to get it nice and tight. I also do this on all my servo extension/connections. My next solution is to cut and solder extension wires. Although I have not tried this on any of my connectiosn, I have read in Model Aviation that dental floss tied tightly around a connection is also a good way to prevent connectors from loosening.