Nitecore UMS4 USB Charger

I like this charger because it accepts longer batteries. I have 18650 batteries that have the plastic ring around the positive post. This charger will not charge that style battery directly because the plastic ring around the positive post of the battery prevents the positive poles from touching. I use a small alnico magnet on the positive post and it solves the issue. All other chargers I have will not allow the fit this nitecore charger does. Wish it had a usb output port to charge other items.

Best Feature(s):Can see charging current and other details like electrical resistance, etc.Value For Money:Yes, as can charge many different sizes, as well as both NiMH, Li-Ion, and other types.Product Quality:GoodCharger works and shows many battery details when C and V button is pressed. Its best to read the instructional manual to unleash the full potential of the charger, as holding down C and V has different functions.Fast charging feature requires chargers with QC features, and charger has usb chargin

All You Require Is A USB Socket!!!

I am EXTREMLY pleased with my purchase of the two units I bought. I LOVE that I do not need to 'find' an un-used electrical socket to plug into. I have USB sockets almost everywhere throughout the home, so that is a HUGE plus for these two bettery chargers.The best thing, regarding the device, is how EASY it now is for me to see batteries needing to be replaced. I have other 'chargers' that will allow this, but only by knowing how to GET to the resistance feature. The "NITECORE" device AUTOMATICALLY SHOWS YOU THE VALUES!!! I don't have to remember special key presses and such. YAY!!!I bought TWO of the devices, but if this-here "Old-fart", what's in his 70s, starts getting geared back up again towards needing to have heaps of charged batteries 'at the ready', ... MoreI am EXTREMLY pleased with my purchase of the two units I bought. I LOVE that I do not need to 'find' an un-used electrical socket to plug into. I have USB sockets almost everywhere throughout the home, so that is a HUGE plus for these two bettery chargers.The best thing, regarding the device, is how EASY it now is for me to see batteries needing to be replaced. I have other 'chargers' that will allow this, but only by knowing how to GET to the resistance feature. The "NITECORE" device AUTOMATICALLY SHOWS YOU THE VALUES!!! I don't have to remember special key presses and such. YAY!!!I bought TWO of the devices, but if this-here "Old-fart", what's in his 70s, starts getting geared back up again towards needing to have heaps of charged batteries 'at the ready', so-to-speak, I just may end-up getting a few more!!!OH! I just remembered. Pulling the connectors to fit in batteries? SILKY SMOOTH with NO binding. THANKS, "NITECORE"!

Bad assembly on 2 out of 3 products

The LCD screen of the first charger was poorly assembled where the fasteners were melted plastic instead of screws. I was able to fix it myself. The second charger had problems with poorly made welds and again I was able to make the necessary repairs. As for the third charger, without even having put batteries, it indicates an EEEE message. Poor manufacturing quality. This brand is definitely to be avoided.

Best Charger Ever

This charges everything! Get one! I have a dozen 18650 Li-ions that I thought were dead. This restored them and saved me, at least, $150. It's paid for itself 4 times over. I've come across some 21700 batteries that would not fit in other chargers. They fit in this charger. They also have great customer service. They have a phone # and a human being actually answers it. Just try that with Amazon or Ebay. You can get the best price on any of their products on their website, the nitecorestorestore. Start your own account with them and get notified of special offers.

Capable, imperfect

My other charger is an Opus 3100 v2.2 which is incredibly intuitive and easy to use, this one a little less so. But I appreciate the micro USB input instead of the barrel plug. The Nitecore has some flex to the PCB holding the click buttons so when you depress them, the nearby edges of the LCD distort. The internal resistance measurement isn’t very accurate or consistent. Pros over the Opus is that it fits 70mm cells and is quiet with no fan, although that could also be a con when using faster charge rates and building up more heat.

Charges fine, but battery health rating is questionable

I've used this to recharge some Eneloop AAA batteries a few times. Charging works fine, but only 1 of the 4 slots reports a good health rating for the very fresh batteries I've used it with so far (all purchased at the same time and have the same amount of cycles). The other 3 slots always say the battery health is poor. If I swap the batteries around, the ratings for each slot stay the same, so the internal resistance measurement can't be trusted.For the price point, this is a decent charger, but it's disappointing that not all the features work, or at least not across all slots. I haven't tried it with other battery sizes yet, so I can't speak on how it performs with those.

Excellent charger

I really like this charger as it can charge different sizes of battery at the same time. I use mine mainly for 4 x Li-ion batteries. The charger according to Nitecore is built of fireproof material so a good option for use with Li-ions although I hope its never put to the test.Once plugged in via the micro USB port the charger needs no setting up, it just does its own thing which is good. The 18W limitation assists in maintaining charge current which in turn reduces the risk of over heating as Li-ions can get hot if charged at high current, I have no problem erring on the side of caution.There is a clear display which shows each slot in turn and can be selected with the left hand button - so for each slot you can see battery charge current, voltage and mA/hr ... MoreI really like this charger as it can charge different sizes of battery at the same time. I use mine mainly for 4 x Li-ion batteries. The charger according to Nitecore is built of fireproof material so a good option for use with Li-ions although I hope its never put to the test.Once plugged in via the micro USB port the charger needs no setting up, it just does its own thing which is good. The 18W limitation assists in maintaining charge current which in turn reduces the risk of over heating as Li-ions can get hot if charged at high current, I have no problem erring on the side of caution.There is a clear display which shows each slot in turn and can be selected with the left hand button - so for each slot you can see battery charge current, voltage and mA/hr charged. Theres also a Good / Poor / Bad based on internal cell resistance and this has shown up a few elederly Ni-MH batteries.Its worth a mention the Nitecore UMS4 will also charge the larger C & D type 1.5v rechargeables, but you can only fit two at a time due to size.Overall an excellent charger from Nitecore and I'd buy it again for sure.

Heats Ni-MH heavily, rather disappointing.

I bought this charger for both Li-Ion cells (mainy 18650) and Ni-MH (AA, AAA). I wanted a USB powered charger as I always have a multiport USB power suppy (both at home and while I travel). This charger seemed to check all the boxes (although USB C port would be nicer in something bought in 2019).Initially I was satisfied with the charger as it charges both Li-Ion and Ni-MH fast. That is until I noticed the Ni-MH batteries to be hot when I picked them up after charging (especially AAAs). I use black Eneloops which are in good shape (checked with another charger) so this was unsettling.What's more I often had problems with placing the AAs and AAAs in the charger properly. Just laying them in the bays often caused bad connection and false indication of a high ... MoreI bought this charger for both Li-Ion cells (mainy 18650) and Ni-MH (AA, AAA). I wanted a USB powered charger as I always have a multiport USB power suppy (both at home and while I travel). This charger seemed to check all the boxes (although USB C port would be nicer in something bought in 2019).Initially I was satisfied with the charger as it charges both Li-Ion and Ni-MH fast. That is until I noticed the Ni-MH batteries to be hot when I picked them up after charging (especially AAAs). I use black Eneloops which are in good shape (checked with another charger) so this was unsettling.What's more I often had problems with placing the AAs and AAAs in the charger properly. Just laying them in the bays often caused bad connection and false indication of a high internal resistance. This is caused by poorly shaped connectors.If it comes to internal resistance value, the result seems to be almost random (the same battery can show different resistance when placed in different bays).

Not sure what more you could ask for in a charger.

I have more battery chargers than I care to admit. I use my chargers for everything from AAA to 21700. It's that last one that has always given me problems. Until I came across the UMS series from Nitecore that is, every other charger I have hits a hard stop on the spring loaded battery bay when inserting a 21700 and you basically have to force it down while risking the integrity of the outer wrapping. This isn't the case with the UMS series. There's about half an inch of additional play in the spring loaded bay which makes inserting and removing these larger batteries sooo much easier.Couple that with the clear and informative display and you've got yourself one of the most versitile chargers on the market. Oh and not to mention that it's powered by a USB port ... MoreI have more battery chargers than I care to admit. I use my chargers for everything from AAA to 21700. It's that last one that has always given me problems. Until I came across the UMS series from Nitecore that is, every other charger I have hits a hard stop on the spring loaded battery bay when inserting a 21700 and you basically have to force it down while risking the integrity of the outer wrapping. This isn't the case with the UMS series. There's about half an inch of additional play in the spring loaded bay which makes inserting and removing these larger batteries sooo much easier.Couple that with the clear and informative display and you've got yourself one of the most versitile chargers on the market. Oh and not to mention that it's powered by a USB port means you can take it anywhere and always be ready to charge.The optional QC3.0 adapter they include isn't a knock off, it's well built and works perfectly.