It could've would've should've if you weren't reading battery volts with a meter that puts a load on the battery. then it could've been the battery....I've seen brand new spectrum switches bad from the box. perhaps if the connections were looked at, or a range check had of been done after your crashes, this last crash would've not happened. I am surprised that you hesitate to solo with your instructor but you fly alone away from your field with ease..perhaps you should've spent more time with your instructor.
good luck with your fixin, have fun.