Battery that does not let you down

"Sisu" is a word for perseverance in Finnish, a unique ability to withstand any challenges that one may face. SISU battery product line is the most recent development of Geyser Batteries, and rolling out in the next 3 years. This line has started with a specific customer case and is currently in the development phase.
SISU batteries can be operated safely for hours and hours, and be charged in a matter of a minute. Just like all of the Geyser ECRs, water-based electrolytes make SISU a safe and high-performing solution for opportunistic charging of buses and ferries, or for any other application where perseverance is required.

Product examples




  • 12V, custom designs (voltage, power)

  • Extremely fast charging (seconds to minutes)

  • Long discharge time (days)

  • High energy-density 

  • 1.000,000+ charge-discharge cycles

  • Used at -40 to +60 °C


  • Safe: non-toxic, non-flammable

  • Structural integration

  • Sustainable

  • Long life 15+ years

  • Maintenance-free

Characteristics table here 

Black and White Traffic


Internet of Things (IoT)


SISU is fitted for any application where safety and several hours of operation are the key criteria.