Review on Treva 10-Inch Portable Desktop Air Circulation Battery Fan 🌬️ - Stay Cool Anywhere with 2 Cooling Speeds and AC Adapter by Jess Chen

Worked on batteries for 9 HOURS! I received two of these devices for an outdoor event. I brought along some D batteries, assuming this thing would just blow them apart (no fan can run 8 hours, right?!). At first I did what the instructions said and turned both fans on low, but 30 minutes after turning them on, my wife turned them on high. We were under a retractable event tent on a concrete road in 95 degree Florida heat. After a few hours we just forgot they were battery operated and random people came into our tent to steal some air from our fan (haha). Then at the end of the event I realized we never changed the batteries and those damn fans ran non-stop for NINE HOURS. Both are flawless. Needless to say, they will be with us from now on. I am very impressed, especially by what happened the next day. So we brought these devices home, I took out the batteries and ended up putting one by my bed to run at night as they had a nice breeze. I connected this fan. At about 10:00 am the power went out due to a thunderstorm, but this fan continued to run for 5 minutes. I was flabbergasted when the batteries died and I had no idea how the fan could still work. It turns out that the fan is so efficient that it literally consumes the accumulated charge in the power supply capacitor, which the device uses to power it. To be honest I can't express how impressive this is. WITHOUT BATTERIES. NO ENERGY. And this thing still ran for 5 minutes using only the stored charge in the power supply plugged into the outlet. although everything else in my house was dead!