A single-cell charger built for versatility
The Klarus K1 is a single-cell USB charger designed for flashlight users, camera owners, and anyone with gear running on swappable cells. Its promise: one small unit able to recharge nearly every battery and cell format on the market.
From 10440 to 26650, plus NiMH and NiCd
On compatibility, it covers a wide range of Li-ion and LiFePO4 cells, from the tiny 10440 up to the 26650, including the common 14500, 16340 (RCR123A), 17500, 17670, 18350, 18490, 18650, and 22650. It also accepts NiMH and NiCd batteries in AA, AAA, AAAA, and C sizes, making it a versatile companion despite its single bay.
Two speeds to choose from, no screen to track charging
Use stays simple: a single button lets you select the chemistry of the inserted cell and the charging current, 0.5A or 1A, while an indicator light shows progress and then charge completion. A reactivation function can even revive Li-ion cells that have dropped to zero volts, provided they aren't irreversibly damaged.
Standard protections, a sturdy shell
The charger automatically cuts power once charging is complete, avoiding overcharge, and includes protection against reverse polarity and short circuits. Its fire-retardant ABS shell and design built for heat dissipation make it a sturdy backup charger, built to travel.
A model pulled from the official catalog, replaced by the K1 Pro
This historic model in the Klarus lineup has since been replaced in the official catalog by the K1 Pro, which adds USB-C and charging up to 2A. The original K1 remains available through certain resellers, but this situation is worth knowing before buying: long-term support and availability now depend on existing stock rather than ongoing production.
Who the K1 is for
This charger suits anyone wanting a compact, highly versatile single-cell model to top up a flashlight or camera cell while traveling, without needing to charge several cells at once.
To charge several cells simultaneously or with a precise tracking screen, a model like the Nitecore UMS4 or the Xtar VC4SL remains preferable. The K1 Pro, the official successor with USB-C and 2A, is also worth comparing before buying.
