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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
Commercial Ferry


Digital social media

Internet of Things (IoT)


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

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