It happens that the solar battery goes out of order and does not give out the voltage declared by the manufacturer. Most often, this is due to the Schottky by-pass diode that burned inside it. To solve this problem, you must perform the following actions:
– Measure the voltage of the solar battery. Even at this stage, we can make an assumption, how many diodes went out of order. Most often, three diode barriers are install in the panels, each of which is responsible for a certain number of photocells and serves as the main component for preventing the shadow effect.
In the event of failure of one of the diodes, the total voltage will decrease by one third, and if two – by two thirds, respectively. With the combustion of all diodes, the voltage of the solar panel can be only a couple of volts, and this despite the fact that when testing it for a short-circuit current, the amperage will remain within normal limits;
– Open the junction box of the solar panel and find the installed diodes;
– Take the tester and call each diode;
– Identify which of the diodes breaks. The burnt diode can be determined visually – its “feet” will be much darker in color than the whole and have a matte shade. It can also be easily determined by temperature – a burnt diode will have a temperature much higher than an unburned diode (it can even be burned);
– Remove the burnt diode. Usually diodes are simply press by clamping contacts, which must be move away with a small screwdriver and alternately pull out the “antennae” of the diode;
– Mount a new diode with the same characteristics. For example, if a diode is write 20SQ045 – this means that this Schottky diode, and has the following parameters: 20 amperes and 45 volts.
The installation is carry out in the reverse order: a small screwdriver removes the terminal blocks and the contacts of the Schottky diode are alternately insert, if necessary, it is pressed slightly;
– Close the junction box and measure the voltage of the solar panel. If everything is do correctly, the voltage of the panel will be within the limits specified in the technical passport.
In emergency cases, for example, when there is no way to replace a broken diode, you can simply dismantle it and then the solar panel will again give out normal voltage. In this case, it can lead to a rapid overheating of the photocells. It will not be protect from the shadow effect.