The quality on this charger is very nice. The issue I'm having is the fact that it doesn't come with a block or a power usb adapter for the wall. If I use my IPhone block it has an output of 1A and it takes from 6 to 8 hours of a full charge but when I use my Samsung block with 1A the charger and batteries get so hot that the screen starts to flicker and start to like melt down and black spots start to appear like if their was too much power going through which shouldn't be the case.

Convenient and fast

This charger is very convenient with the cord storage on the back panel, as well as efficient with such fast charging. My only comment is that sometimes the batteries will show 100% until someone touches the charger or battery, then the battery percentage will drop down between 5-10%. Still a wonderful purchase and worth the price. Wish I would have bought a bigger one!

Excellent basic charger.

The USB cord arrives attached to what I assume is the pass-through port on the back - charging is via the micro-usb slot on the top. While lacking more advanced features of other chargers (such as setting the amps/full discharge etc but what do you expect at this price?), it is solid, reliable and does a good job. There is a switch on the top to specify whether you are using a power source or battery to charge it but I'm not sure what the difference is other than the display dimming slightly. Perhaps (and I haven't tested this) it turns off completely when the battery is fully charged. Excellent item for what it is and the price.

Get this, don't get that other one you have seen!

So, this is the only charger I will buy. I tried one of the newer (Nitecore NEW i4) and would assume that the (Nitecore NEW i2 would be the same) chargers but they did not charge the battery completely, this was also mentioned by other people on the net so I sent the i4 back. These Nitecore UM20 USB Chargers are quality chargers and I do highly recommend them.. Not mentioned in descriptions anywhere is the fact that these chargers also can accomadate and charge the dual 20700 batteries which are larger than the 18650.. These are what I use.. Last for years with no issues.

Great unit for traveling

Compact unot great for travel usb connection and usb pass through for connecting to smartphone or phone chargers or anything that requires a usb on the go. 2 settings for priority 1 setting for battery charger priority which charges at 1 amp or 2nd setting usb priority which makes whatever charging priority at 5v and 1amp and puts charger into .5 amp load for a slower battery charge. Overall great product but LCD display backlight could be brighter for seeing at night. Overall great buy and compact to carry in car at all times in case your mod batteries or say a 18650 flashlight battery would go out. Buy and you won't be disappointed.

Impressive

I figured it would be slow because I normally do not like USB type chargers. But it charges my 18650 vape batteries quickly. I really like it's digital readout screen and safety features as well. I hooked up a volt meter to it while it was charging completely discharged batteries and it charges perfectly. When finished I tested the batteries with a battery tester and they were at 100%. Batteries were not undercharged or overcharged. This is a great little charger I am very pleased with it. Compact, simple to operate, not a cheap knock off, or second. This it is a genuine. So if you want a good charger give this one a try. I would recommend this to a friend.

Look for another

I bought this thinking it would be good but it wasn't. Unfortunately within 10 mins of use the screen on one half blacked out and then eventually came back to normal but one charging bank stopped working. I have the same branded charger but the i4 which is much better. Just spend a little more and get that as I've had it for years without any issue.

Pleasantly surprised!

After a bad experience with a cheap knockoff wall charger, when I realized I needed to plug this charger into a USB port on my PC, or use a USB wall charger, I figured it would take days to charge even a single 18650 battery (as the cheap wall charger did). I could not have been more wrong! While this unit only charges one battery at a time, it will charge a fully depleted 18650 in a matter of hours, and then begins charging the second battery when the first is recharged. I can fully recharge two 18650 batteries overnight, using only a 500mA USB 2.0 port on my PC! I have not tried it using a 2.1A wall charger, but I would imagine that it charges even faster. You won't regret this charger!

Power to the people

I found the device reliable, efficient and accurate. I tested the MAH both entering and leaving the batteries to verify the authentic and accuracy of the device. It also remains rather cool, and slows down the charge to prevent the batteries getting too hot. Nice, cheap and functional for the price. When batman, and every other super hero wants to charge their taser / rocket launching / fire starting 18650 batteries they don't just use any old charging device. Nope they attach this baby to their 2amp plug socket and fire it up. Warning, though don't be putting your tongue over the + / - terminals it tingles and makes you think of beetle juice, beetle juice, beetle juice. (well it did for me)

Screen lighting design is poor. Much harder to read the screen than it should be in my opinion.

The way they chose to light the screen on the UM20 results in a poorly and unevenly lit screen which make it difficult to see the status of the batteries day or night, particularly night. Just be aware that the screen will not be fully lit like a majority of the other chargers with screens. The pictures make it look a bit brighter and easier to read than it actually is. Still works well.