I’m not new to this product—I previously owned the older version with a micro USB connection. With this newer version, I can clearly notice that the charging speed is much faster.
Charge two 18650, 21700 or AA cells fast, and watch every detail on the screen.
An intelligent two-bay charger that reads each cell, picks the right current and shows you voltage, capacity and health while it works.
- Two independent bays, each charging its own cell at its own pace
- Up to 3,000mA in a single bay, about 55 minutes to 80% on a 3,500mAh cell
- 4,000mA total output when both bays are loaded over a QC source
- LCD readout of current, voltage, capacity, internal resistance and time
- Charges IMR, Li-ion, LiFePO4, Ni-MH and Ni-Cd from 10440 up to 26700, plus AA to D
- Reverse polarity, short circuit, overtime and over-discharge protection built in
- Fire-retardant PC body with cooling fins for safe, stable charging
Fast enough to charge between trips.
With a QC source plugged in, a single bay pushes up to 3,000mA, taking a 3,500mAh cell to about 80 percent in roughly 55 minutes. Drop a flat 21700 in after work and it is ready for the head torch or the EDC light by the time you have eaten.
Load both bays and the UMS2 shares its 4,000mA total across them, so a pair of cells still tops up quickly while you get on with packing.
See exactly what each cell is doing.
The LCD shows live charging current, voltage, charged capacity, internal resistance and elapsed time, alongside the charging mode it has chosen. A glance tells you how full a cell is and whether an old one is still healthy.
When you want to take charge yourself, set the charging current and cut-off voltage by hand for a particular cell. The information enthusiasts want is right on the panel.
One charger for the whole battery drawer.
The UMS2 reads each cell, identifies the chemistry and capacity, then selects the right voltage and one of three charging modes. It handles IMR, Li-ion, LiFePO4, Ni-MH and Ni-Cd cells from a 10440 up to a 26700, plus AA, AAA, AAAA, C and D.
That covers the cells in your flashlights, head torches, cameras and tools, so one unit sits on the bench instead of a tangle of single-cell chargers.
Two bays that charge on their own terms.
Each bay runs its own charging cycle, so a half-empty 18650 and a fully flat 21700 each get the current they need at the same time. Pull one out the moment it is done and leave the other to finish.
The total output reaches 4,000mA from a Quick Charge source, with up to 2,000mA going to each cell when both bays are working together.
Power it from whatever you have on hand.
The UMS2 takes its power over a single USB cable, so a wall adaptor, a power bank or a solar panel can all run it. On a camp trip or a long drive, top up your cells from the same battery pack that charges your phone.
It accepts a QC 2.0 input for full speed, and falls back gracefully to a standard USB supply when that is all you have.
WHY THE UMS2 OVER A BASIC CHARGER
You can read the cell, not guess
The LCD shows live current, voltage, capacity and internal resistance. A simple charger gives you a single status light and no way to spot a tired cell.
Up to 3,000mA, not a slow trickle
A single bay charges at up to 3,000mA over QC, so cells are ready in well under an hour rather than overnight.
One unit for every chemistry
IMR, Li-ion, LiFePO4, Ni-MH and Ni-Cd from 10440 to 26700 and AA to D, all detected automatically. Most basic chargers stick to one or two sizes.
Protection you can leave running
Reverse polarity, short circuit, overtime cut-off and temperature regulation keep an unattended charge safe. A cheap charger often has none of these.
Safe charging you can walk away from.
A built-in temperature regulation system watches the heat and keeps the charge stable, while reverse-polarity, short-circuit and overtime protection guard against the usual mistakes. Leave a pair of cells charging while you sleep or work, and the UMS2 holds them safe.
Over-discharged cells get an activation step, and Li-ion restoration can bring a flat cell back, giving older batteries another run instead of the bin.
Built to take a knock and shed heat.
The shell is moulded from fire-retardant PC, so it stands up to the rough and tumble of a kit bag and to the demands of higher-current charging. Cooling fins along the body draw heat away from the cells for a steady charge.
At 157.7g and 152mm long, it slips into a pack as easily as it sits on the bench at home.
WHERE THE UMS2 EARNS ITS PLACE
Flashlight & EDC
Keep a pair of 18650 or 21700 cells topped up and ready, with the screen showing which one still has life left.
Home Battery Bench
One charger for the whole drawer, from camera 16340s to AA and D cells, each detected and charged to the right voltage.
Travel & Outdoors
Light and compact, run from a power bank or solar panel, so your cells charge wherever the trip takes you.
Battery Enthusiasts
Set the current and cut-off voltage by hand, and read internal resistance to track how each cell is ageing.
COMPATIBLE BATTERIES
| TYPE | SIZES | WORKS |
| IMR / Li-ion / LiFePO4 | 10440, 14500, 14650, 16500, 16340 (RCR123), 16650, 17350, 17500, 17650, 17670, 17700, 18350, 18490, 18500, 18650, 18700, 20700, 21700, 22500, 22650, 25500, 26500, 26650, 26700 | Yes |
| Ni-MH / Ni-Cd | AA, AAA, AAAA, C, D | Yes |
RECOMMENDED CABLE
Use a USB cable rated to carry the full 18W input so the charger reaches its top speed.TECHNICAL SPECIFICATIONS
| Charging bays | 2 (independent) |
| Input | DC 5V/2A, 9V/2A, 18W (MAX), QC 2.0 |
| Output voltage | 4.35V / 4.2V / 3.7V / 1.48V (±1%) |
| Output current (QC) | 3,000mA x1 (MAX), 2,000mA x2 (MAX) |
| Output current (standard) | 2,000mA x1 (MAX), 1,000mA x2 (MAX) |
| Total max output | 4,000mA |
| Charging modes | CC, CV and -dV/dt (auto) |
| Display | LCD: current, voltage, capacity, resistance, time |
| Body material | Fire-retardant PC |
| Dimensions | 152mm x 73mm x 40mm (5.98" x 2.87" x 1.57") |
| Weight | 157.7g (5.56 oz), cable not included |
| Download Instruction Manual (PDF) | |
FREQUENTLY ASKED QUESTIONS
Will it charge the batteries I already own?
If your cells are IMR, Li-ion, LiFePO4, Ni-MH or Ni-Cd, the answer is almost certainly yes. The UMS2 takes round Li-ion cells from a tiny 10440 up to a 26700, which covers 18650 and 21700, and it also charges AA, AAA, AAAA, C and D. It detects the chemistry and capacity on its own and sets the right voltage.
Can I charge both bays at 3,000mA at the same time?
The 3,000mA figure is the maximum for a single bay. With both bays in use the charger shares its 4,000mA total output, giving up to 2,000mA to each cell over a Quick Charge source. Charging one cell at a time is the way to reach the full 3,000mA single-bay speed.
What does the screen actually show me?
The LCD reports live charging current, battery voltage, charged capacity, internal resistance, elapsed time and the charging mode in use. Internal resistance is a useful health check, since a cell that reads high is on its way out. You can also set the current and cut-off voltage by hand when you want manual control.
What's In The Box
- 1x UMS2 Charger - intelligent two-bay USB charger
- 1x USB-C Cable - for connecting to your power source
Fast, smart, two-bay charging for every cell you carry.
GET YOUR UMS2 CHARGER NOWYou’re Backed by Our 60-Day Ironclad Guarantee
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Try it for 60 days. If it’s not right for you, send it back.
We stand behind our gear. If you’re not happy with your purchase, just return the full package within 60 days and we’ll issue a full refund—no fuss, no forms, no hoops to jump through.
What Happens After You Order
- You’ll get an instant order confirmation email with your receipt.
- We’ll pack your order the next working day and send you a tracking number once it’s on the way.
- From the moment you order to the moment it reaches your hands, we’re here to keep you updated and supported.
When will I receive my gear?
- Singapore: Delivered to your doorstep in 4–6 working days.
- International: Arrive within 10–14 working days.
Returns and warranty
- Every product comes with a 1 to 3-year replacement warranty (depending on the item).
- If anything isn’t working right, just let us know. We’ll make it right.
FREE Gift with Purchase: Limited Edition Ember Shard Whistle
Spend $99 or more today, and we'll automatically include a limited-edition Glow-in-the-Dark Ember Shard Whistle when packing your order.
Charge it quickly under sunlight or your flashlight, and enjoy its subtle glow throughout the night—perfect for marking gear, emergency kits, or attaching to your bag.
Limited quantities. These will be swapped (at our discretion) to other gift items if shards are unavailable.
Customer Reviews
Overall rating: 4.9 / 5 from 190 reviews.
Good
Speed:Good Display:Good Versatility:Good Item as described. Can charge my Li-ion and Ni-MH batteries. Good price during promo and fast delivery.
Great charger! I bought it to charge some 18650's, and it works flawlessly. It feels premium, looks very nice, and has so much versatility.
Speed:very fast and stable Display:LCD is very clear, provides all relevant information Versatility:works on my intended batteries type
This is my second purchase, and once again, I am very pleased with its performance. It charges the batteries quickly, and the display is clear and easy to read.
Product Quality:Good Best Feature(s):Good Value For Money:Best
This is one of the few smart chargers that i have research and can accept any kinds of rechargeable batteries unlike the one earlier charger that isnt reliable and has charging limiter on it.
I was initially sceptical about this product, as it is more expensive compared to other brands available online. However, I decided to give it a try. The moment it arrived, I unboxed it and tested it by charging a battery. To my surprise, it performed really well. The charging speed is fast and efficient. Overall, I have no regrets purchasing this product. It’s definitely worth the price.
I have been using Nitecore lights for more than 13 years, starting with the EA4 (860 lumens). I also purchased the P10 V2 a few years ago. Recently, I needed an extra battery and received a complimentary CI2 charger. MJ was very friendly and provided helpful advice throughout the process. Thank you!
Very cool. Serves my needs as I have different batteries models. Don’t need to worry about getting different charger. Besides there are indicators display that makes charging effortless.
This was a much needed upgrade from my old off brand battery charger. It automatically recognizes the battery type and gives the recommended charging parameters, so all you have to do is insert the batteries and it does the rest. It has more flexibility with the usb c charger so you don’t need a wall outlet. It can charge four 21700 batteries at once and that’s what I really like about this thing.
Best Feature(s):light weight Product Quality:very good Value For Money:yes First time buy this charger.Affordable price. If good will buy more
Good charger which shows the battery voltage and how many bars too. Thanks
The best function of the UMS4 it revive the over discharged battery every info of charging status is shown
Nitecore has always been a great brand to have for all their adventure torch lights, battery accessories and other adventure gadgets. I've been with them since the Tin2 pocket light and still working well! Today I tried their latest battery charger UMS4 and it's simply awesome! A great intelligent charger & capable of fast charging! I really love it. I continue to look forward to more great Nitecore products by the local distributor. Awesome & brilliant! Thank you.
The charger works as described. Able to detect one of my battery as poor charging. Check and found some residual on the battery, clean it and it works well again. This is the advantage of using this charger caused it can detect issues with individual battery.
No frills, Flfast and reliable battery charger. Well build and comes with a good quality Type C cable.
It displays all the information about the battery during charging, certainly this is worth buying. Thanks.
It’s a great charger which give all the detail technical information that I need. It even better now with the 3A USB C which I have been waiting since my very first (more than 9yrs ago, still working well) Nitecore 4 then the UMS4 (2A) and preorder this new model once it was announced. Though I don’t use very much but I appreciate innovative good quality product.
Very good quality. The charging speed is fast.
Very convenient and fast charging. Able to monitor each battery power level while charging and automatic termination after charging completion. Thumps up! 👍
Purchased this after my D2 charger finally broke down after 8 years! Easy to use and now comes in a USB-C to USB cable. The newer charger has opted for a much more simpler interface (LED lights green and red) compared to the more elaborate D2 display which really looked high tech.
Lightweight and not so bulky.
Main attraction about this charger is: it can revive dead batteries! This can help us to save cost from buying replacement batteries, and stop us from throwing away good batteries which are “dead”. I like how there is a screen where all information are displayed. This is definitely a cool charger and I do recommend people to invest in this.
Compact to bring around and it can revive dead batteries. That’s the whole point of getting this ! And v fast charging
Charge quite fast. Especially when you have more than one battery for a single item, this helps alot.
Best charger I like the display information on all types of battery, worth buying Nitecore product with good solid battery charger.
When I opened the box, I was surprised to see the size of the charger. I thought it would be smaller. However, it works well and I could charge my batteries in a short period of time. Fast charger, would recommend to anyone looking for a good charger.
Well done Nitecord.... Charges majority sizes of batteries & shows all information on batteries that I have never known b4....
Straight forward to use..
UMS2 Worth the investment! Charges any brands of rechargeable batteries. Super fast charging + screen information status is def a winner by itself
No longer wnadering Great charger that shows the health the battery and charging progress! Lightweight and can charge any number and type of battery
Great charger Great charger and it helps me to repair my other brand Li ion battery 🔋 that is Over Discharged and Over Discharged IMR battery Restoration 🔋
Great Charger Bought this to replace my current Nitecore Intellicharger i4 years back, although some slot of the spring become very still but still can use to charge those 18650 batteries. And this new USM4 is a good improvement to charge all types of batteries fast with OLED display that tells you how much volt and current is using and even can revive dead battery. Best part is it will indicate fast charge or normal depend on your power source. Highly recommended!
UMS4 Received it quite fast thats an A+ for me . Tested it out on the QC3 Anker USB charger really love the displayed info on all the different batteries . Don't regret buying the UMS4 at all. 😻
UMS2 Charger It is really fast changing... Love it very much... Will continue to support Nitecore product... Thanks 🙏🙏🙏
Value For Money:good. Product Quality:good Best Feature(s):indicator for individual slot is convenient for user
Works perfectly, It is very nice for a charger.Basicly I bout it because it is a usbc,
I need only one unit to top up my gear of 2 older Nokoser chargers which are able to handle up to 18650 size. By mistake I doubled ywrongly ordering 2 units of this UMS4 chargers instead of one(1) until I received the shipments advice. Now I have to dispose off the 2 older Nokoser Digi D4S chargers.
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