Review on Universal Power Bank Compatible Rechargeable Batteries by Jon Thawngzauk

I bought this because it was one of the cheapest USB chargers on the market. I also bought an expensive XTAR charger with a similar function, but it was over 6 times more expensive. Most importantly, nowhere does it say that the USB output only works with higher voltage lithium-ion batteries. I tried not putting AA batteries in and the USB output didn't work. The manual for my more expensive charger says that only Li-ion batteries power the USB, so I tried this charger by putting 26650 3.6V lithium batteries in it and the USB output worked ! However, it won't turn on until the wall charger cable is unplugged. They must have just added this feature as the manual for mine shows a picture with only a USB charging input. So if you are buying this to use as a battery you MUST use lithium ion batteries which are not available in most stores. My 26650 batteries are $11 each at my local battery store but they have a capacity of 5000mah at 3.6v and hold plenty of current which is what I need in a power outage. I'm giving 4 stars due to the lack of documentation on USB charging requirements and the fact that I almost returned it. If I didn't have special lithium batteries and a more expensive charger that documented the requirement that made me try it, I would assume the USB output isn't working and return it.