To continue off our tutorials discussion at Find Out My Needs, we would like to briefly cover solar panel sizing, and the difference between high and low voltage systems. Read more below and get ready to learn!

Things to Consider When Choosing a Panel

Picking a solar panel to work with is relatively easy. Let’s go over the main issues all of our customers face when making the big decision. 

How much solar do I need?

This is the most complicated question in the way of your decision. Figuring out how much solar you need comes down to totaling your night time and day time watt hour usages, and dividing it by the number of daylight hours in a day. To read more about this process, take a look at our Find Out My Needs tutorial, and get started answering this question!

Is there such thing as 48 volt solar panels? Why not 12 volt?

Matching up panels to your native system voltage can be confusing to beginner solar enthusiasts. This is because the voltage of a system in actuality varies throughout the day depending on its load. Voltage equates to pressure, the same way we can measure water pressure. Depending on the volume of sunlight coming into the system, or volume of electricity being used, your voltage will go up or down. 

This means no panel is guaranteed to be exactly 12 volts, 24 volts, 36 volts, or 48 volts. We can really only give you an average of where the voltage is for the solar panel, or solar system. This "average" number is also known as Nominal Voltage. It is a best guess of the voltage range of a solar product, and is used to pair similar voltages together in a solar array.

To answer your question, voltage ratings are subjective. If you are planning on series wiring your solar panels, find an MPPT charger that can handle the summation of all your solar panels added together. When pairing a solar controller and solar panels together, its not about matching nominal voltage. Its about finding a controller that will handle the range of voltage and amps your solar panel(s) is capable of putting out. 

High or low voltage?

If you're collecting more than 2500 watt hours, you may want to start thinking about using a high voltage solar controller. High voltage solar controllers come in voltage ratings from 120 to 400 watts and above; keeping your amps low for easier transport over long distances. You can find high voltage systems in both off grid and grid-tied projects; everything from tiny homes, remote cabins, to full houses on the grid. Low voltage solar controllers are more affordable, and tend to be used for small projects like camper vans, RV’s, travel trailers, and marine applications. 

Do I have enough space?

Once you’ve figured out how many watts per hour you need to collect, its time to see if you can squeeze enough panels into your space to handle the amount of necessary solar! Use this calculator to in put the dimensions for your panel of choice, and play with the possibilities. 

How far will my solar array be?

Once you’ve figured out how many watts per hour you’ll need to generate, you’ll need to take into consideration how far your panels are away from your solar controller. The farther your solar panels are, the more wire. The more wire, the more resistance. The more resistance, the thicker the wire will need to be. The thicker the wire, the more expensive your project becomes. To alleviate distance problems and wiring concerns, consider using a high voltage system on a series wiring strategy. Play with our wire gauge calculator to understand this property!

How should I cluster the solar array?

Splitting up and clustering the array is a great way to limit the amount of amps coming down your wires. If you’re using this methodology, chances are you’ve figured out your amps are requiring a small fortune in wiring to transport! You may have also discovered your solar controller has a maximum amp rating you are surpassing. This is a great chance to start thinking about series wiring your solar panels, and then splitting them up in the right combination for transport and management of your solar controller. Research about PV Combiner Boxes is a must.  

Which solar controller am I planning on using?