Keeppower 26650 5500mAh

The Keeppower 26650 5500mAh extends the brand's protected line-up, already established in the 18650 and 21700 formats. The principle stays the same: Keeppower selects quality cells from major manufacturers and adds its own built-in protection circuit, rather than manufacturing cells in-house. The result is a rechargeable lithium-ion cell built for very powerful flashlights (search-light or diving types), DIY battery packs and current-hungry electronics.

The 26650 format (1.02 in / 26mm diameter, 2.72 in / 69mm length) is the largest of the common cylindrical formats in the Keeppower range, bigger than the 21700 or 18650. This extra size translates directly into capacity: 5500 mAh typical, with a guaranteed minimum of 5400 mAh. The nominal voltage is 3.6 to 3.7V, and continuous discharge current can reach 10A depending on the version, comfortably enough for very demanding devices. The cell withstands over 500 charge/discharge cycles.

As with the rest of the range, this cell's central asset is its protection circuit (PCB), which cuts power on overcharge, deep discharge, over-current or short-circuit. This safety feature protects both the cell and the device in use, a real plus over a bare 26650 cell, which is trickier to handle safely.

Before buying, check that your flashlight, battery holder or pack accepts the 26650 format, which is larger than a 21700 or 18650: not every device supports it. Keeppower also remains a niche brand, rarely found in mainstream retail, more often available from specialist lithium-cell retailers. For a powerful flashlight or a DIY pack that needs high capacity per cell, this protected 26650 is a safe bet.