Yes Jana, in most cases you can. Solar panels are like beers, you can have two German ones, and then switch to an Irish without any problem. The key is the voltage. If you are running a 12 volt nominal system and have 18 volt open circuit panels, you can get another 18 volt open circuit panel of different size and manufacturer and hook it in parallel with your existing panels. What you can't do is take two 120 panels for example, and wire them in series with a 180 watt panel to get a higher voltage. The larger panel will generate more amps than the smaller ones can accept, and since they are in series, each carries the entire current.
You can even use panels of different voltage in parallel as long as each panel has a bypass diode installed that can handle the voltage of the highest panel, or they are attached to separate charger controllers. An example might be you have two 12 volt nominal panels charging a battery bank, then you acquire a 24 volt panel. As long as the diodes in the 12 volt panels have a peak inverse voltage higher than 24 volts, there will be no problem. You are trying to avoid having the high voltage panel force its power through the low voltage panel. Most panels have diodes of at least 50 peak inverse voltage, and many are higher than this. You can check with the panel manufacturer if the data is not readily available on the panel. Good luck Jana, and take care, Rudydoo
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Yes Jana, in most cases you can. Solar panels are like beers, you can have two German ones, and then switch to an Irish without any problem. The key is the voltage. If you are running a 12 volt nominal system and have 18 volt open circuit panels, you can get another 18 volt open circuit panel of different size and manufacturer and hook it in parallel with your existing panels. What you can't do is take two 120 panels for example, and wire them in series with a 180 watt panel to get a higher voltage. The larger panel will generate more amps than the smaller ones can accept, and since they are in series, each carries the entire current.
You can even use panels of different voltage in parallel as long as each panel has a bypass diode installed that can handle the voltage of the highest panel, or they are attached to separate charger controllers. An example might be you have two 12 volt nominal panels charging a battery bank, then you acquire a 24 volt panel. As long as the diodes in the 12 volt panels have a peak inverse voltage higher than 24 volts, there will be no problem. You are trying to avoid having the high voltage panel force its power through the low voltage panel. Most panels have diodes of at least 50 peak inverse voltage, and many are higher than this. You can check with the panel manufacturer if the data is not readily available on the panel. Good luck Jana, and take care, Rudydoo
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