473 years manufacturer warranty on all IVT products More products and information under www ivt hirschau com A solar module consists of several interconnected solar cells and serves for converting the radiative energy of the sun into electrical energy Direct voltage is provided on the terminals of the radiated solar module If the module is operated within a closed current circuit direct current is available The subsequent diagram shows the idealized current voltage characteristic of a solar module The working point moves between point 1 and 3 depending on which electrical consumer is connected to the solar module Short circuit point The solar module s terminals are shorted this means that the electrical resistance between the terminals is extremely low The highest possible short circuit current IK of the solar module flows at this point Maximum Power Point MPP The solar module provides the highest possible power This is the product of current IMPP and voltage UMPP in MPP Idle point At this point the solar module s terminals are open this means that the electrical resistance between the terminals is extremely high The idle voltage of the solar module can be measured on the terminals Charging with constant voltage U Ladung At the constant voltage charging the charging end voltage Uend will be kept constant during the entire charging process As a result at the beginning of the charging process the flowing current Imax is higher than at the end With the decreasing current towards the end of the charging process the charging of the battery is gentle Charging by pulse width modulation PWM When charging according to the pulse width modulation principle at the beginning of the charging process the battery is charged with maximum current Imax As soon as the cut off voltage Uend is reached the current flow is stopped in order to avoid overcharging After this first charging step the battery is not fully charge most of the time A decrease of the battery voltage is to be expected For this reason the charging current restarts if the voltage Ustart falls short of a certain value This process is repeated until the battery is completely full The charging current phases become shorter as the battery fills up Chart 1 Current voltage characteristic of a solar module SOLAR CELL SOLAR MODULE CHARGING METHODS Voltage IMPP MPP UMPP Current Chart 2 Charging characteristic constant voltage charging Time Imax Uend Current Voltage Chart 3 Charging characteristic PWM charging Time Imax Uend Ustart Current Voltage

Vorschau IVT-Solartechnik-Englisch Seite 47
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