Oldach, R.R.OldachVogt, M.M.VogtKremer, P.P.KremerBopp, GeorgGeorgBopp2022-03-082022-03-081993https://publica.fraunhofer.de/handle/publica/320803The compact state-of-charge detector is being developed to provide the user of a stand-alone photovoltaic system with data about the state of charge of their battery at any time. It is suitable for flooded or sealed lead-acid batteries. It can also be used in emergency power systems, battery powered vehicles or boats. The detector adds up all the energy that goes into the battery and subtracts what is taken out. It also calculates the losses incurred. As the losses increase with battery age, they are calculated again each time the battery is fully charged. The losses in the idle state are also included. Recalibration occurs when the battery voltage is greater than the end-of-charge voltage and the charging current is small. The state of charge of the battery is then displayed. Three relays are acfivated at predetermined charge levels. The relay outputs can be used for various functions such as to display a warning, to disconnect the load, or to automatically start a diesel generator.en621697conference paper