Members thgoebel Posted August 17 Members Posted August 17 (edited) A user of „another“ Shelly forum planned to implement a sprinkler irrigation control system with Gardena magnetic valves. These valve are controlled by 24V AC, which draw 130-150mA. Current value is small enough for an immediate control with Shelly UNI plus outputs. Crucial is however the rated AC voltage for supplying the device: 24V AC (rms) drives the peak voltage at the two electrolytic capacitors (2 x 150μF/35V) to their rated value! Two or three volts more at the transformer shows us a peak voltage of 40V DC. The step down converter TP6841 is rated for 40V DC input. Hence, the limiting factor is the rated voltage of the capacitors. Boosting the capacitors to a rated voltage of 50V inflates the dimensions of the UNI plus slightly: Unfortunately, I didn’t manage to get a 330μF/50V capacitor with max. 8mm diameter and max. 16mm length. A Panasonic type (as depicted) has 10mm diameter. This modification allows the user to build the irrigation system with 28V AC (rms)… Edited August 19 by thgoebel 3 Quote Translate Revert translation? English (American) Finnish French German Italian Portuguese (European) Spanish
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