Nitecore UM2 Charger
(9 reviews)
A compact two-bay charger with a large LCD screen: the Nitecore UM2 recharges over USB at up to 3A and shows voltage, current, capacity and health for each cell.
Characteristics
- Bays: 2 independent bays
- Charging: USB QC input, up to 3A (1 cell)
- Display: LCD: voltage, current, capacity, health
- Compatibility: Li-ion 10440 to 26650 + NiMH AA/AAA
- Large LCD screen and automatic detection
Detailed overview: Nitecore UM2 LCD dual-slot battery charger
The Nitecore UM2 is a smart two-bay charger that made the brand popular with flashlight and rechargeable-cell users. Its idea: power from a simple USB cable, a large and highly readable LCD screen, and automatic detection of the chemistry of each cell inserted, with no fiddly settings.
On compatibility, it is very versatile. It recharges Li-ion, IMR and LiFePO4 cells in the most common formats, from 10440 to 26650, including the 18650, 20700 and 21700 widely used in flashlights, plus rechargeable NiMH batteries in AA and AAA formats. The two bays are independent: you can charge two cells of different types or sizes at the same time.
Speed depends on the power source. Plugged into a Quick Charge adapter, the UM2 delivers up to 3A on a single bay, or 1.5A per bay when both are occupied, enough to recharge a large 21700 quickly. The LCD screen shows in real time the voltage, current, charged capacity, cell type, cut-off voltage and cell health, a far richer readout than simple LED indicators.
Compact and light, the UM2 slips easily into a bag or a drawer. It protects against reverse polarity and short circuits, and stops charging at the end of the cycle. For anyone who wants a reliable, complete and affordable two-bay charger that reports precisely on the state of their batteries, the UM2 remains a safe bet.
Full specifications
Detailed characteristics (EAN: 6952506492787)
Charging capacity
| Number of slots?Number of batteries that can be charged at the same time. | 2 |
|---|---|
| Compatible formats?Accepted battery formats (AA, AAA, 18650, 21700...). | AAAA, AAA, AA, C, D, 10440, 14500, 14650, 16340, 16650, 17350, 17500, 17650, 17670, 18350, 18490, 18500, 18650, 18700, 20700, 21700, 22650, 25500, 26650 |
| Compatible chemistries?Recognised battery chemistries (Li-ion, LiFePO4, NiMH, NiCd...). | Li-ion, LiFePO4, NiMH, NiCd |
| Max charging current?Maximum charging current per slot, in milliamps. | 1500 mA |
| Adjustable charging current?The user can manually pick the charging current. | Yes |
| Independent charging per slot?Each slot manages its own charge, independent of the other cells (different formats and chemistries can be mixed). | Yes |
Power input
| Power source?Built-in mains plug, USB port (Micro-USB or USB-C) or 12 V car socket. | USB-C |
|---|
Output and features
| USB output (device charging)?The charger can also act as a power bank: it uses the inserted cells to charge another device. | No |
|---|
Display and diagnostics
| Display?Type of visual feedback on charging status. | Detailed LCD screen |
|---|---|
| Automatic chemistry detection?The charger automatically adapts its charging profile to the inserted cell, with no manual setting. | Yes |
| Test / repair functions?Advanced functions beyond plain charging: real capacity measurement, internal resistance, reconditioning of worn cells, discharge cycles. | Real capacity test, Reconditioning / revival |
Size
| Weight?Weight of the empty charger, in grams. | 5.2 oz (148 g) |
|---|---|
| Dimensions (L × W × H)?Length × width × height, in millimetres. | 6 × 2.9 × 1.6 in (152 × 73 × 40 mm) |
Warranty
| Warranty?Length of the manufacturer's warranty. | 1 year |
|---|
User manual / Instructions for use (PDF)
Our tester's review: Christophe Delpuech
The Nitecore UM2 is the two-bay charger we drop into the bag when we want something serious without the bulk. Two bays, a large and very complete LCD screen that shows voltage, current, charged capacity, cell type and even health, and fast charging that, with a Quick Charge adapter, reaches up to 3A on a single bay. It swallows 18650, 20700, 21700 and 26650 cells without straining their wraps, and also takes AA and AAA NiMH. We like its simplicity: plug in over USB and read everything at a glance. Two honest reservations: you need a Quick Charge adapter to get full speed, and there is no clean shut-off without unplugging. But for monitoring and recharging your cells day to day, at this price, it is hard to fault.
Frequently asked questions: Nitecore UM2 LCD dual-slot battery charger
Li-ion, IMR and LiFePO4 cells from 10440 to 26650 (18650, 20700, 21700, 26650...) plus NiMH batteries in AA and AAA formats. It automatically detects the chemistry of each cell inserted.
Plugged into a Quick Charge (QC) adapter, it delivers up to 3A on a single bay, or 1.5A per bay when both are occupied. With a standard USB source, charging is slower.
Its large LCD screen shows in real time the voltage, charging current, charged capacity, cell type, cut-off voltage and health of each cell, for precise monitoring.
Yes. The two bays are independent: you can charge two cells of different chemistries, sizes or charge levels at the same time, for example an 18650 and a 21700.
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Published on 02/09/2026