Nitecore UMS4 Intelligent USB-C Four Slot Quick Battery Charger for Li-Ion/Ni-MH/Ni-Cd/IMR 16340 14500 18650 21700 20700 AA AAA and More Batteries, with Organizer

Great charger that shows voltage, current, and time of charging. It cannot sense between Li-ion and LiFePO4 batteries, so when charging LiFePO4 (lithium-iron phosphate) batteries, the charging voltage has to be changed or it will overcharge them.

This is my 2nd one. The first one lasted for MSN years and charged thousands of batteries

Totally worth it so I can charge my batteries! USB-C is a plus! User friendly, a bit big but hey, it has 4 slots for batteries. Overall very satisfied with my purchase!

Auto identifies the cell type and charges. Reads cell internal resistance and the total energy put into each cell. USB powered. A quality slow charger!

This review is for Nitecore UMS4I bought this to revive a battery for my TT20 flashlight that recently stopped working, and when I tested the voltage with a multimeter, it was like .03, so I figured that was the issue. This recharger was able to revive it, but it was a bit tricky. With only that battery in the recharger, it would not stay on longer than 30 seconds or whatever the auto shutoff timer is. When I put it on the charger, it was recognizing there was a battery there, but would not stay on. I was able to get around this issue, by placing another battery in a different slot, and have it charge while the problem battery was getting recharged. It took awhile, and I had to replace the extra battery that I was using to keep the unit on (swapped to another battery that needed recharging). Eventually, the battery I was reviving had enough charge for the unit to stay on, and it fully charged, and works now.Since a brand new battery of that kind (thrunite 21700 proprietary battery) was almost as much as a charger, I figured I would just get the charger and see if it works, and it did. The charger itself seems decent enough, the display was bright, and it presented all the information that I needed. I really dislike how it uses usb micro, but with all the adapters and bricks I have laying around, it's not a big deal I guess.

Works well, helped to rejuvenate a few of my batteries.

Great product

Does the job. The charging contacts are spring loaded and the wells are deep to accommodate different battery sizes. This makes each battery have a "sweet spot" on the charging contacts, it will read correctly if positioned well or show a faulty reading if not. It require too much fiddling for my taste.