Handheld Fan, Portable Fan, 4000mAh USB Rechargeable Personal Fan, 180° Foldable Mini Desk Fan with 6 Wind Speed, LCD Digital Display, Lanyard as Neck Fan, Ultra Quiet, Pocket Size for Indoor Outdoor

BLUF (Bottom Line Up Front) Very effective, value priced, dual purpose Fan/Battery Bank. What a great idea! A personal fan that can keep you cool for 5 - 16 hours (claimed) depending on which of the 6 speeds you choose (so it COULD run all night) and is claimed to recharge in 1.5 hours (Ill have to see if it really can use a Fast charger pulling all 2.4 amps - which would then take 1.67 hours to put in 4 amp hours). Also a neat feature is the power meter that shows you how much energy remains in the battery. It comes with a soft neck lanyard and a USB-A to USB-C charging cable, you provide the charging block. So - as originally received, it came charged to 68%. I connected it through my digital tester to a USB port rated for 3 amps, but this device only pulled 0.85a. So I moved it over to my QC3 port - rate dropped to 0.82a. At 0.85a going from 69% (when I started my watch) to 100% (delta = 31% or 1.2 aH) Id expect charging to be finished in 1.47 hours. After 20 min, charging had dropped to 0.70a (74% charged). I removed the USB tester and directly connected the fan to the power supply (5v 3a port). 10 min later charge had increased by 2% with 22% remaining till full = estimate now is 110 min to full charge. FINALLY at 100%, a 31% overall increase, took 2 Hr 15 Min. So No - you cant fully charge this from empty to full in 1-1/2 hours as claimed. Rundown testing started at 100% battery and fan level 6 (High - moving a LOT of air). 1 hour later charge remaining was 76% (delta 24% suggesting a little more than 4 hours at full speed). Switched to Level 3 (?1/2 speed) - still moving lots of air dropping 16% over 82 minutes suggesting an 8.5 hour run-time at that speed. Then switched to Level 1 - still an effective breeze - dropping only 6% over 3.5 hours - suggesting a 58 hour run time at low speed. YMMV. Please note the above analyses assume linear battery charge/discharge characteristics which may not necessarily be the case.