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.
A two-bay USB-C charger you can run off your power bank, anywhere.
Top up your 18650, 21700, AA and more from a power bank, laptop or wall adapter, with up to 3A into a single slot.
- 2 independent slots, charge up to 2 batteries at once
- Up to 3,000mA into one slot in Fast Charge Mode
- USB-C input at 18W, with QC and PD fast-charge support
- Works with Li-ion, IMR, Ni-MH and Ni-Cd cells from 10440 to 26700, plus AA, AAA, C and D
- Powered by power banks, solar panels, laptops or USB wall adapters
- Per-slot LEDs show charge level and mode at a glance
- 120.4g and 148mm long, sized to travel in a pocket of your kit
Up to 3A into a single battery.
In Fast Charge Mode the Ci2 puts up to 3,000mA into one slot, so a high-drain 21700 is ready again in a fraction of the time a basic charger takes. Nitecore measured roughly 35 minutes to take a 3,500mAh cell from 30 percent to 80 percent.
Charge two cells together and each slot runs at up to 1,500mA, so a pair of 18650s tops up while you pack the rest of your gear.
USB-C in, so it charges wherever you do.
The single USB-C port takes power from almost anything with a USB output. Run it off a 20,000mAh power bank at camp, your laptop on a train, a wall adapter at the hotel, or a folding solar panel in the field.
The plug is reversible, so it goes in the right way every time. One small charger covers home use and travel, instead of leaving a wall-only unit behind.
Fast Charge Mode from QC and PD sources.
Plug the Ci2 into a Quick Charge or Power Delivery adapter or power bank and it steps up to Fast Charge Mode, reaching that full 3,000mA into a single slot. The 18W input draws from 5V, 9V or 12V sources, so it makes the most of the chargers you already carry.
One charger for almost every cell you own.
The Ci2 handles Li-ion and IMR cells from the tiny 10440 up to the 26700, alongside Ni-MH and Ni-Cd in AA, AAA, AAAA, C and D. So your flashlight 21700s, headlamp 18650s and the AAs from a remote all charge in the same unit.
A charging program tuned for IMR cells watches the whole cycle and holds the cut-off voltage within safe limits, which helps your batteries last longer.
Each slot charges on its own terms.
The two slots are controlled independently, so you can mix a 21700 in one and a 14500 in the other and each gets the right treatment. The Ci2 detects the battery, then picks between three charging modes, CC, CV and -dV/dt, to match the chemistry and capacity.
Slot your cells in any combination and it sorts out the voltage and current for each one, so you do not have to.
A quick look tells you where each cell stands.
Every slot has its own row of indicator LEDs. A constant red light means the slot is in Fast Charge Mode, and the green lights show roughly how full the battery is, one green for about 30 percent, two for about 80 percent and three for 100 percent.
So a glance across the unit tells you which cells are still working and which are ready to go back in your gear.
Built to charge safely, trip after trip.
Cooling fins along the body pull heat away as the cells charge, and the casing is moulded from durable, fire-retardant PC that shrugs off knocks and grit on the move. Reverse-polarity and short-circuit protection guard against a cell slotted the wrong way.
Overtime protection ends the charge if a cycle runs long, and over-discharged cells can be woken up and brought back to a usable state.
WHY THE Ci2 OVER A BASIC BATTERY CHARGER
Charges from a power bank
USB-C input runs off power banks, laptops and solar panels. A mains-only charger stays plugged into a wall at home.
Up to 3A fast charging
QC and PD input unlocks 3,000mA into a single slot. Many basic chargers trickle at a few hundred milliamps.
One unit, many chemistries
Li-ion, IMR, Ni-MH and Ni-Cd from 10440 to D in the same two slots. Cheap chargers usually lock you to one size.
Independent, intelligent slots
Each slot detects the cell and picks its own mode, so mismatched batteries charge correctly side by side.
WHERE THE Ci2 EARNS ITS PLACE
Travel
One small charger powered by your existing USB adapter or power bank, so you leave the bulky wall unit at home.
Everyday Carry
Keep the 18650s and 21700s for your flashlights and gear topped up at your desk over USB-C.
Field & Outdoors
Run it off a folding solar panel or a power bank at camp to keep two cells charged away from the grid.
Backup & Prep
A single charger that takes nearly every cell in the house, from AA remotes to C and D lanterns.
CHARGING CURRENT
| MODE | 1 SLOT | 2 SLOTS |
| Fast Charge | 3,000mA max | 1,500mA max each |
| Standard | 2,000mA max | 1,000mA max each |
COMPATIBLE BATTERIES
| IMR / Li-ion | 10440, 14500, 14650, 16340 (RCR123), 16500, 16650, 17350, 17500, 17650, 17670, 17700, 18350, 18490, 18500, 18650, 18700, 21700, 22500, 22650, 25500, 26500, 26650, 26700 |
| Ni-MH / Ni-Cd | AA, AAA, AAAA, C, D |
TECHNICAL SPECIFICATIONS
| Slots | 2 (independent) |
| USB-C Input | 5V⁃2A / 9V⁃2A / 12V⁃1.5A, 18W (max) |
| Fast Charge Input | QC and PD supported |
| Output Voltage | 4.2V±1% (Li-ion) / 1.48V±1% (Ni-MH/Ni-Cd) |
| Max Single-Slot Current | 3,000mA |
| Charging Modes | CC, CV and -dV/dt (auto-selected) |
| Indicators | Per-slot LEDs (red Fast Charge, 3 green charge level) |
| Casing | Fire-retardant PC with cooling fins |
| Dimensions | 148mm x 65mm x 37mm (5.83" x 2.56" x 1.46") |
| Weight | 120.4g (4.25 oz) |
| Download Instruction Manual (PDF) | |
FREQUENTLY ASKED QUESTIONS
Can I run the Ci2 off a power bank?
Yes. The Ci2 is powered entirely through its USB-C port, so any power bank, laptop, USB wall adapter or USB solar panel can run it. For the full 3,000mA Fast Charge Mode, use a source that supports Quick Charge or Power Delivery.
Which batteries fit the Ci2?
It charges Li-ion and IMR cells from 10440 up to 26700, which covers common sizes like 14500, 16340, 18650 and 21700, as well as Ni-MH and Ni-Cd in AA, AAA, AAAA, C and D. The two adjustable slots take different sizes at the same time.
Can I charge two batteries at once?
Yes. Both slots work independently and at the same time. Charging one cell gives it up to 3,000mA, and charging two together runs each slot at up to 1,500mA in Fast Charge Mode.
What's In The Box
- 1x Nitecore Ci2 Charger - intelligent USB-C dual-slot charger
A USB-C cable is not included. Use any USB-C cable rated for up to 18W charging.
Fast, flexible charging for almost every cell you carry.
GET YOUR Ci2 CHARGER NOWYou’re Backed by Our 60-Day Ironclad Guarantee
 |
 |
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.
Products related to this item
Recently viewed
Get help choosing the perfect light for your task, and have it delivered on the same day!
If you can't find what you are looking for, or need delivery on a specific date, WhatsApp us below.