Interested in Solar Panels and you want to understand more?!

This post will give you a basic understanding of wiring, the 1st image outlines a basic system.


What does it mean to wire solar panels in series?

When an installer connects your solar panels in a series, he is wiring each panel to the next.

This creates a string circuit (2nd image).

The wire running from the panel's negative terminal is connected to the next panel's positive terminal and so forth down the line for one path of current for a continuous, closed loop.

The important difference between wiring panels in series or in parallel is that electrically it affects the voltage and amperage of the resultant circuit.

In a series circuit you sum the voltage of each panel to get the overall voltage of the array. However, the amperage of the overall circuit stays the same stays the same.


What does Wiring panels in Parallel mean?

Wiring solar panels in a parallel fashion is a little bit more complicated (3rd image).

Instead of connecting each panel to the next, each panel is connected to a centralized wire coming from your roof.

There is one wire for connecting the wires from all the positive terminals and one wire for the wires from the negative terminals.

With panels connected in parallel the voltage of the overall circuit stays the same as the voltage for each panel but the amperage of the overall circuit is the sum of the amperage of each solar panel.

Wiring solar panels when using a string inverter:

When using a string inverter. the string inverter will have a rated voltage window that it need from the solar panels to operate and also a rated current that the inverter can operate with.

Remember string inverters have MPP trackers in them that vary current and voltage to produce maximum power and so when designing these machines they need to have a range of what voltage and current will be receiving from the solar array.

In most crystalline solar panels the open circuit voltage is around 40 Volts and for most string inverters the voltage window is between 300 to 500 volts. This would mean that when designing a system you could have between 8 and 12 twelve panels in series.

However, often an array might be larger than 12 panels and so it is common to actually have two strings of 8 or 9 panels in series but then have two strings to be in parallel.

Which wiring works better – series or parallel? (4th image)

In theory, parallel wiring is a better option for many electrical applications because it allows for continuous operation of the panels that are not malfunctioning.

But, it is not always the best choice for all applications. When designing your solar system, your installer might decide that series wiring is better suited for your application or he might choose a hybrid approach by series wiring some panels and parallel wiring others.

When designing your solar system, a critical balance of voltage and amperage needs to be achieved for it to perform at its best.

This is where mixing parallel circuits with series circuits is beneficial. When solar panels are wired in a series, voltage is additive, but the amperage stays the same.

For example, if you have five panels that are 12 volts and 5 amps each, an array that is series wired would have 60 volts and 5 amps.

But if you parallel wired those same five panels the amperage would be additive, while the voltage remains the same.

Therefore, you would have 12 volts and 25 amps instead.

I hope this basic information helps those considering implementing Solar Panels!