Solar panels feature positive and negative terminals. Wiring solar panels in series means wiring the positive terminal of a module to the negative of the following, and so on for the whole string. This wiring type increases the output voltage, which can be measured at the available terminals.
It is the current the solar panel produces when no load is connected to it. Short-circuit current (Isc) can be measured by connecting the positive and negative terminals of the panel to each other through an ammeter in series. While measuring Isc on your own is usually safe and does not harm the panel, care must be taken to avoid arcing.
The open-circuit voltage (Voc) can be obtained by simply measuring the voltage across the positive and negative terminals of the panel using a voltmeter. It’s important to remember that Voc represents the maximum voltage a solar panel can produce under standard test conditions.
The positive and negative terminals of the panel are located at either end of this series. One of the easiest ways to identify the positive and negative terminals of a solar panel is to look for the markings on the back of the panel itself. Most panels will have a label or sticker that indicates which end is positive and which end is negative.
If you look at a solar panel datasheet and compare the current at maximum power point (Imp) to the short circuit current (Isc) you will notice the short circuit current is not significantly higher than the normal operating current. Therefore there is very little potential for panel damage by simply touching the wires together.
Wiring solar panels in series requires connecting the positive terminal of a module to the negative of the next one, increasing the voltage. To do this, follow the next steps: Connect the female MC4 plug (negative) to the male MC4 plug (positive). Repeat steps 1 and 2 for the rest of the string.