Mixing and Matching Solar Panels

While it is best practice to use one type of solar panel for your array, sometimes it is necessary to mix and match panels. Mixing solar panels of various voltages or wattages, or produced by different manufacturers, is a frequently asked question by most DIYers. When adding different solar panels to your array, each panel's electrical parameters (voltage, wattage, amps) needs to be carefully considered. We want the electrical parameters to be similar to each other - the closer the better. Our systems generally go out with either 100w or 370w solar panels. Over the years some panel manufacturing specifications have changed slightly,  so it is always best practice to locate your solar panels specifications sticker. On the back of each solar panel is a sticker with all the electrical parameters needed when comparing panels to each other. They typically look like this: 

Adding Panels in Series Only

When adding panels together in series with the same amperage (Isc/Imp) we can stack the solar panel voltages (Voc/Vmp) together. Here is an example of having 3 panels of one type, and a different one. 

As we can see, having a single panel of lower voltage brings the overall power down by a few volts compared to having 4 of the same panel. This would be an ideal scenario as we only lose out on 3% of overall wattage. Next let’s take a look at having panels in series with different voltages and amperages. 

When adding panels together in series with different amperages a lot more power is lost. The overall current of the panels is determined by the lowest performing panel. Once we have the lowest amperage value we can add our voltages together. 

Here we can see that the limiting single panel brings the other down with it in terms of power output. When able, matching panels of similar amperage is best.

Adding Panels in Parallel Only

When adding panels in parallel with the same voltage we can stack the solar panels amperage together. Here is an example of all the same panels and one panel with a lower voltage. 

We can see that adding a panel of lower voltage in a parallel connection lowers the overall voltage of all the other panels. When adding panels in parallel only it is best to match voltages rather than amperages. 

Adding Panels in Series and Parallel

When adding panels in strings of series and parallel connections, both of the above rules apply. The overall amperage and voltage of each set of panels is determined by the lowest producing panels. In this case there is no best option when it comes to matching up panels based on similar voltages vs amperages. 

If you have any questions on adding extra solar panels to your array or using your own solar panel array, feel free to give us a call at [phone].