Light, compact and safe lithium battery with integrated battery management. The system can be charged with the normal common chargers for AGM or Gel battery. Ideally for the exchange of common batteries (no mixed operation types). High discharge current: The battery can be discharged within a short time without suffering damage, thereby a discharging of 90% is not a problem for a short time. The battery can be charged only in 1 hour. Up to 4 batteries can be switched in row. The integrated battery management protects the battery against low- and excess voltage. Due to the high possible current drain the capacity of 40Ah battery approx. corresponds to a 80Ah AGM-battery.