Kinda a dumb question...but here goes. I recently wired up two fans inside my fett helmet with a single 9 volt battery and a single switch. The dual fans are draining the single battery pretty quickly (I went to a Halloween party and it was dead after about 4 hours of occassional use).

Is there any advantage to wiring multiple 9 volt batteries in a series, or do I need to worry about too much voltage going to the fans?

Sorry if this is a stupid question, but I would hate to fry my Sgt. Fang.