The four-bay big brother of the UM line
The Nitecore UMS4 is the four-bay version of the UMS line, built for anyone charging a lot of cells: flashlights, vaping gear, cameras, or RC hobby equipment. It plugs in via a simple USB-C cable and automatically detects each inserted cell's chemistry.
From 10440 to 26650, Li-ion and NiMH alike
Its compatibility is very broad. It charges Li-ion, IMR, and LiFePO4 cells in the most common formats, from 10440 to 26650, including 18650, 20700, and 21700, as well as rechargeable NiMH batteries in AA and AAA sizes. All four bays are independent: you can charge four cells of different types, sizes, or charge levels at once.
Up to 3A per bay, with a Quick Charge adapter
Speed depends on the power source. Plugged into a Quick Charge adapter, the UMS4 delivers up to 3A on a single bay, and up to 4A combined when several are occupied. With a standard USB supply lacking QC, charging stays noticeably slower.
An LCD screen that really shows everything
The large LCD screen displays in real time, for each cell, the voltage, charging current, capacity charged, detected cell type, cutoff voltage, and health status, a far richer readout than simple indicator lights. It's one of the most complete displays observed in this segment.
The unit also offers functions to measure real capacity, test internal resistance, and regenerate tired cells.
Complete protections, but no clean shutdown
The UMS4 protects against reverse polarity and short-circuits, and stops charging at the end of each cycle. In real use, though, the unit stays powered as long as it's plugged in: there's no clean shutdown of the screen or electronics without physically unplugging the cable, a practical quirk rather than a safety flaw.
The manufacturer warranty is one year, a standard length but shorter than some rivals in the same segment.
Who the UMS4 is for
This charger suits anyone with several cells of different formats (flashlights, cameras, RC hobby gear) who wants to charge and monitor them precisely without multiplying chargers.
For simpler use limited to household AA/AAA batteries, a more basic charger like the Panasonic Eneloop BQ-CC55 is plenty and costs less.
