 Hot glue is a great way to burn your fingers, but also very handy for adding simple strain relief to electronics wiring. It works well for those stranded wire connections. Battery cases, PCB wiring, really any wiring that needs to stand up to some movement during usage. Before applying, make sure you've got a good solder joint first. Then test to ensure the glue will stick well to the PCB and wire insulation. Add a healthy ring of glue around the base of the joint. Alternatively, you can lay the wire flat and glue it down to protect the solder joint even more. If you need to remove it, use some rubbing alcohol to release the adhesion. Just turn off your glue gun first.