KLARUS K2A Smart Dual Slot Charger and Power Bank | 18650, 20700, 21700

Key Features

Two independent slots is the starting point, but what actually separates the K2A from a basic dual-bay charger is how it allocates current: up to 2A when only one bay is loaded, dropping to 1A per bay once both are running at the same time, rather than a fixed rate applied regardless of how many cells are actually charging. QC3.0 and PD3.0 input support means that rate is genuinely achievable with a compatible fast-charging adapter, not just a specification on paper that a standard 5W phone charger can't actually deliver.

Physical compatibility is worth calling out specifically: the K2A accepts protected cells up to 78mm long, longer than many dual-bay chargers on the market allow, which matters because a protected 18650 or 21700, the version with a built-in safety circuit adding a few extra millimetres of length, is exactly the kind of cell that gets rejected by chargers sized only for bare unprotected cells.

Key features

• Digital display shows live voltage and charge percentage, per bay
• USB-C/USB-A port doubles as a power bank output
• Handles 18650, 20700 and 21700, protected or unprotected
• QC3.0 / PD3.0 fast charging input

The same USB-C/USB-A port that accepts input power doubles as an output for charging a phone or small device directly from whatever cell is currently seated in the unit, turning the charger itself into a compact power bank during a blackout without needing to remove the battery and put it in a separate power bank shell.

Battery and cable are sold separately, since buyers typically already have preferred cells.