I had been looking for a portable USB charger for my Nikon D500 batteries and it was not just available. I found something but it was not compatible with USB except it was just portable enough without an extra cord to be plugged on the wall, so it was just compact.
I finally found the Nitecore UNK1 USB portable charger in which it passed all my required needs in portability and charging. First of all this charger fits in one’s hand and the USB end plug hides within the charger itself. You have to pull it out from the side and then you can charge it on portable power banks and USB hubs that you can plug on wall sockets.
The Nitecore UNK1 can charge to different Nikon batteries at the same time and it is made of durable materials that can withstand outdoor activities and punishment. The best thing is, it is a smart charger in which there is a small screen displaying charging temperature, amount of power is being taken by the battery, and charging time left. It can also stop charging by itself when it detects that the battery is full.
The last time I used it in my car it was fantastic, I don’t have to use my car power inverter anymore in which it is too bulky and takes a lot of space in which it is a annoying to arrange at the driver’s seat space.
Aside from my Nitecore UNK1 for my D500 batteries, Nitecore also made chargers for Canon, Sony, and Gopro. This company also have fantastic flashlights and chargers for the conventional AA and AAA batteries.