A modest 800% improvement for the previous 2h uptime with 4* AA batteries. I did not realize even it's quite clearly stated in the package that the 9v battery is ~160mAh and AA battery is up to 2000mAh! I was probably the last one to figure this out. Apparently the 9v battery is only ok for one remote control IR LED and giving nice shocks to your tongue. Where are the lighter-sized cold fusion fuel cells. Industry, please respond, it can't be that difficult. You are just protecting your oil shares.