K2 2.85V/3400F Cell

The newest member of Maxwell Technologies’ K2 family of ultracapacitors is the 2.85-Volt, 3400-Farad cell. It expands the power range of the K2 family by 17% and the energy range by 23%, making it the most powerful cell available in the industry-standard 60 mm cylindrical form factor. It is also the first cell to incorporate Maxwell’s DuraBlue™ Advanced Shock and Vibration technology. Products with DuraBlue technology are tested to some of the most demanding environmental requirements for transportation, increasing vibrational resistance by approximately three times and shock immunity by four times when compared to ultracapacitor-based competitive offerings. Simply put, it the world’s most ruggedized cell.

The K2 family features a 60 mm diameter cylindrical design and an electrostatic storage capability that can cycle a million charges and discharges without performance degradation. They are available in quick- and easy-to-implement threaded terminals or in compact, weldable terminals.

These cells are ideal for transportation applications – including public transit vehicles and heavy transportation – where the shock and vibration environments are the most severe. They also provide extended power and energy availability for longer periods of propulsion in automotive subsystems. They provide faster response for critical information in UPS/Backup Power applications and in grid applications, they enable critical information to remain available during dips, sags and outages in the main power source. In addition, they can relieve batteries of burst power functions, thereby reducing costs and maximizing space and energy efficiency.

The K2 family of cells work in tandem with batteries for applications that require both a constant power discharge for continual function and a pulse power for peak loads. In these applications, the ultracapacitor relieves batteries of peak power functions, resulting in an extension of battery life and a reduction in overall battery size and cost.

In applications where power is needed in spikes, the K2 family provides a "green” power solution to reduce peak power demands on the grid, batteries or generators. And, like all Maxwell ultracapacitors, the K2 series is capable of accepting charges at the identical rate of discharge.


  • BCAP3400 P285 K04
  • BCAP3400 P285 K05


  • Automotive subsystems
  • Hybrid vehicles
  • Rail
  • Heavy industrial equipment
  • Hybrid and Plug-in Hybrid Bus
  • Wind turbine pitch control
  • UPS & telecom systems

Features & Benefits*

  • Up to 1,000,000 duty cycles or 10 year DC life*
  • Highest power and energy
  • Up to 18 kW/kg of specific power
  • Up to 4.00 Wh of stored energy
  • Threaded terminals or laser-weldable posts
*Results may vary. Additional terms and conditions, including the limited warranty, apply at the time of purchase. See the datasheet, warranty details and enclosed information for applicable operating and use requirement.