carry your rig on, be friendly and explain to them that you are a professional audio technician and that you have a bag full of pro audio gear... do this before your bag even goes through the xray machine.
one piece of advice, never refer to a battery as a battery, call it a power supply instead... TSA people freak out about batteries
this may even be in the archive and if it's not it should be, it seems like someone asks this question every couple of months