Charging arrangement for solar tracker comprising at least one solar panel and rechargeable batteries, the batteries are configured to feed a respective solar tracker controller through connection to a string in solar fields, the string comprising a series-connected set of solar panels and configured to feed a grid or a load, the charging arrangement for solar tracker comprising: a first power converter with an input and an output, wherein the input is connectable in series to the string and configured to provide a first constant voltage at its output when it is working, and comprising a protection configured to prevent an open circuit; an isolated battery charger configured to charge the rechargeable batteries, the isolated charger comprising an input and an output, wherein the output is connected to the rechargeable batteries and the input is connected to the output of the first converter, the charging arrangement for solar tracker being characterised by: said first converter being configured to: retrieve at least a part of power coming from the string and deliver it to the isolated battery charger, and switch off when there is no current flowing through the string, or switch on when there is current flowing through the string, and a second power converter being a panel powered power converter, the second power converter comprising an input and an output, wherein the input is connected in parallel to the at least one solar panel and configured to operate delivering power to the isolated battery charger when the first power converter stops operating, and the output is connected to the output of the first power converter; wherein the at least one solar panel is connectable in series to the string, the second power converter is further configured to provide a second constant voltage at its output, being said second constant voltage lower than the first constant voltage, and the isolated battery charger being further configured to convert power to feed the rechargeable batteries, said power coming from: the first power converter when there is current flowing through the string, or from the panel powered second power converter when there is no current flowing through the string; the charging arrangement further comprising a diode, the anode of the diode is connected to the output of the second power converter and the cathode of the diode is connected to the output of the first power converter and the input of the isolated battery charger, the diode is configured to avoid short circuit when said outputs feed the isolated battery charger. a first power converter with an input and an output, wherein the input is connectable in series to the string and configured to provide a first constant voltage at its output when it is working, and comprising a protection configured to prevent an open circuit; an isolated battery charger configured to charge the rechargeable batteries, the isolated charger comprising an input and an output, wherein the output is connected to the rechargeable batteries and the input is connected to the output of the first converter, the charging arrangement for solar tracker being characterised by: said first converter being configured to: retrieve at least a part of power coming from the string and deliver it to the isolated battery charger, and switch off when there is no current flowing through the string, or switch on when there is current flowing through the string, and a second power converter being a panel powered power converter, the second power converter comprising an input and an output, wherein the input is connected in parallel to the at least one solar panel and configured to operate delivering power to the isolated battery charger when the first power converter stops operating, and the output is connected to the output of the first power converter; wherein the at least one solar panel is connectable in series to the string, the second power converter is further configured to provide a second constant voltage at its output, being said second constant voltage lower than the first constant voltage, and the isolated battery charger being further configured to convert power to feed the rechargeable batteries, said power coming from: the first power converter when there is current flowing through the string, or from the panel powered second power converter when there is no current flowing through the string; said first converter being configured to: retrieve at least a part of power coming from the string and deliver it to the isolated battery charger, and switch off when there is no current flowing through the string, or switch on when there is current flowing through the string, and a second power converter being a panel powered power converter, the second power converter comprising an input and an output, wherein the input is connected in parallel to the at least one solar panel and configured to operate delivering power to the isolated battery charger when the first power converter stops operating, and the output is connected to the output of the first power converter; wherein the at least one solar panel is connectable in series to the string, the second power converter is further configured to provide a second constant voltage at its output, being said second constant voltage lower than the first constant voltage, and the isolated battery charger being further configured to convert power to feed the rechargeable batteries, said power coming from: the first power converter when there is current flowing through the string, or from the panel powered second power converter when there is no current flowing through the string;