How To Wire Solar Panels : Series vs Parallel Wiring

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How To Wire Solar Panels

Solar energy is becoming more accessible and homeowners are utilizing it to power their homes. With the increasing need to conserve energy, most people are embracing more natural ways of generating energy.

Homeowners and DIY (Do It Yourself) enthusiasts often wonder how to wire solar panels to produce the maximum energy output.

One of the effective and simple ways to increase your capabilities of solar power is to wire solar panels together.

To note however, is to select the connection method that will have a configuration that is the most energy-efficient depending on the size and equipment, as well as your needs. Wiring solar panels shouldn’t be so difficult. With a little tweak, it’s quite doable.

The energy production capacity of a solar panel is measured in watts, which is achieved by multiplying the amps of current and its voltage. It is critical for you to find an appropriate balance of amps and voltage for the system to perform well. Then you get a better return on investment.

The main difference between wiring solar panels in series vs. parallel is that the voltage and amperage of the circuit will be affected.

In this article, you will learn how to install your desired connection, why certain types of wiring are utilized, and which type is most beneficial to you.

Types of Solar Wiring

There are basically three types of solar wiring; series wiring, parallel wiring or a combination of series and parallel wiring.

You are probably trying to figure out if you should connect your solar panels in series or parallel.

Don’t fret. We’ll have a look at each.

1. Wiring Solar Panels in Series

This method is used to specifically increase the voltage of the total solar panel system. The current travels along only one path. This means that all the circuit current must pass through all loads.

Since the series circuit flows in a single line, any damage to one point of the string will affect the entire circuit.

For example, most old Christmas lights are of the series circuit. If one bulb is affected, the rest of the string lights go off. Modern Christmas lights use parallel wiring, fortunately.

The series wiring is normally used when charging a controller that needs more than 24 volts or an inverter that is connected to a grid.

Steps for Connecting Solar Panels in Series

The series circuit is achieved by connecting the positive (+) terminal to the negative (-) one for each panel.

This will then leave you with one available negative (-) terminal and one available positive (+) terminal, that will be connected to the charge controller or inverter.

1. Wiring Solar Panels with Similar Characteristics in Series

Wiring Solar Panels in Series

The solar panels in this method are similar in power rating and type. The voltage from each panel is summed up to make the total voltage while the amperage remains unchanged. For instance, 3 solar panels with a power rating of 6V/3A each will produce 18V/3A.

2. Wiring Solar Panels of Different Voltages in Series

Wiring Solar Panels in Series

These solar panels have a similar current rating but different voltage. When wired in series, the amperage remains intact while the voltage increases.

Example; 3 solar panels with a rating of 5V/3A, 7V/3A, and 9V/3A produce a power output of 21V/3A.

3. Wiring Solar Panels of Different Amperage in Series

Wiring Solar Panels in Series

The solar panels, in this case, have different voltage and amperage ratings. The voltage will be added up as before but the amperage will adjust to read the value represented by the lowest solar panel.

For instance; 3 different solar panels with a power rating of 3V/1A, 7V/3A, and 9V/5A will have a total power output of 19V/1A reducing its efficiency drastically.

Advantages of Solar Panels in Series

  • Each solar panel’s voltage is summed together while the amperage remains the same. For instance, if you have 4 solar panels and each panel has 12 volts and 5 amps, then the entire system will have 48 volts and 5 amps.
  • Since the current remains unchanged, you can save up on installation costs as you can get away with smaller wiring.
  • You can have long wire runs without necessarily having to lose out on electricity. That’s why most solar panels for home use are partially wired in series.

Disadvantages of Solar Panel Series Wiring

  • The amperage remains constant.
  • There’s reduced efficiency when connected to solar panels with different power ratings as the panel with the lowest amperage will dictate the total current output.
  • If one solar panel is damaged or has a connection problem, the rest of the system collapses as well.

2. Wiring Solar Panels in Parallel

The parallel circuit is slightly complex when compared to the series circuit. It has multiple paths as opposed to only one. It is the reverse of the series circuit as it is ideal for boosting the system’s current (amperage).

The voltage in parallel solar panels remains the same while the current is additive. For instance, if you have 4 solar panels with 15 volts and 6 amps each, the total system will have 15 volts and 24amps.

Steps for Connecting Solar Panels in Parallel

This method involves connecting the negative (-) terminals together and the positive (+) terminals together leaving you with a free negative (-) and positive (+) terminal to connect to your batteries.

Wiring Solar Panels in Parallel

If you are wiring solar panels of the same characteristics (same power rating and identical) in parallel, the total voltage would remain unchanged with increased amperage. For example, 3 solar panels with a rating of 6V, 3A, when wired will become 6V, 9A.

What if non-identical solar panels with different voltage and amperage rating? In this case, the amperage will add up while the voltage will adjust to have the lowest value.

For solar panels to be effective in parallel wiring, the voltage must remain unchanged. This means that a panel with a higher voltage will drop its rating to be at the same rating with the panel that has the lowest voltage.

Case in point; 3 different solar panels with a rating of 3V/1A, 7V/3A, and 9V/5A will have a total power output of 3V (lowest voltage) and 9A.

Advantages of Solar Panel Parallel Wiring

  • It is considered best for household wiring. Most household circuits use parallel wiring as the multiple paths allow for current to flow irrespective of one broken component.
  • Damage on one panel does not affect the rest the solar power system.
  • Amperage is increased.
  • It offers more flexibility when it comes to off-grid systems. For example, your 12V battery can be charged by a 12V solar power system.

Disadvantages of Solar Panel Parallel Wiring

  • Wiring panels in parallel can be quite costly as it requires more wire to facilitate the multiple connections and heavier wire that can handle the additional current.
  • The voltage remains constant.
  • Can be a bit complex and time consuming to install.
  • Parallel wiring may require additional equipment like a combiner box or branch connectors.

3. Combination of both Series and Parallel Connections

Wiring Solar Panels in Series and Parallel

If you want to maximize on the advantages of the parallel and series wiring, you can opt to combine the two circuits in your solar power system. Depending on what your requirements are, you can achieve the desired amount of current or voltage with this option.

Most solar panel systems are usually limited by the charge controller. These charge controllers are designed to only accept a specific amount of voltage and amperage. Hence, for larger systems, there is a need to utilize a combination of the series and parallel circuits so as to remain within those parameters.

For this type of wiring, 2 or more panels need to be created in series. The same needs to be done for the parallel circuit.

For instance, to avoid massive power loss, 4 panels in series are supposed to be parallel with the other 4 panels in series.

There really isn’t any disadvantage with the parallel and series combination; hence it is important to know how to wire solar panels with this method.

Final Thoughts

While we have had an in-depth look into how to wire solar panels, it is important to have in mind that each type of wiring system has its pros and cons. It might seem easier to opt for the series wiring, yet a disruption to one component will affect the rest of the system making it less reliable.

Diversely, parallel wired solar panels require long and expensive wire.

Wiring solar panels in series and parallel allow you to maximize the voltage and amperage of the system making it more energy-efficient.

Your choice of wiring will depend on the size of the installation, where the panels and inverter will be placed, and whether you are grid-connected or not.

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