Solar Panels Series Vs. Parallel – A Guide on How to Wire Solar Panels

ByDonna Vanpelt

Solar Panels Series Vs. Parallel – A Guide on How to Wire Solar Panels

If you’re a newbie to the inner workings of solar energy systems, you’ll probably get lost when you see this topic. Parallel and series wiring refers to the major wiring methods used for installing solar panels. How your panels are installed matters a lot because it influences the performance level of your panels and even the kind of inverter you have to involve in your setup.

Read on to know all you need to know about both wiring methods, how to install your panels in parallel and series, how they compare against each other, and which one is better.

Solar Panels in Series

This wiring method has to do with the solar panel terminals, both the negative and positive terminals. To form a series connection, you have to wire the positive terminal of one panel to the negative counterpart of another panel. With this wiring method, you create a photovoltaic source circuit, resulting in at least two panels stringed together from positive terminals to negative terminals.

The major highlight of this wiring method is that it will enhance the pressure or force moving your electric current through the circuit. However, the supply of electric current is constant. Let us quickly paint a practical installation scenario for you to understand it better. If you’re installing solar panels with a rating of 60 volts and 10 amps, stringing four of these panels in series will give you a total voltage of 240 volts and a total amperage of 10 amps.

This is the primary reason solar installers use the series wiring method to improve the voltage, which is essential for the solar inverter to function properly. For instance, if your inverter’s voltage requirement is 480 volts, you need to install 10 panels with a 48-volt rating in series to meet that requirement.

Wiring Your Solar Panels in Series

Let us show you how to wire your solar panels in series, one step at a time. We’ll begin with the materials needed for this process.

What do You need?

∙ The required number of solar panels you need. (Ensure that they are identical. For some reason, if you can’t get identical solar panels, at least ensure that their current ratings are similar)

  • Multimeter
  • Blankets
  • The Wiring Process
  1. Pinpoint the negative and positive solar wires, so you don’t mix them up when the process is underway. Some cable manufacturers make it easier by marking their negative cables with (-) and positive cables with (+). If you’re not so lucky to get these kinds of solar cords, it’s not a big deal. Aside from checking the cables, you can also check the junction box or the MC4 connectors.
  2. For some reason, if there’s no indication whatsoever on your cables, you can use a digital multimeter to check the open circuit voltage of your panels. If your meter displays a reading for negative voltage, the cable connected to your meter is the negative cable. On the other hand, if the meter displays readings for positive voltage, the cord connected to your meter is the positive cable.
  3. Spread a blanket or a very large cloth on the floor before turning your panel upside down so its surface will be face down on the covered floor. The blanket will prevent scratches on the panel’s surface. Turning your panel upside down will expose its wiring and prevents it from receiving solar energy from the Sun.
  4. Get the positive cord from the first panel and the negative cable from the second one and join them together by plugging one into the other.
  5. To connect more panels, join their positive solar wires to the negative wires of the panels you’ve strung so far. That’s how you wire panels in series.

After this, you can link your charge controller to the batter.

Then link your charge controller to the panels.

Return the panels to their original position.

Solar Panels in Parallel

Unlike wiring panels in series, which involves joining the positive cable of one panel to the negative cable of another panel, wiring panels in parallel requires linking the positive cable to the positive cable of the other panel, and the same applies to the negative cables as well. There’s usually a combiner box containing the negative and positive connectors. The positive cables are fastened to the positive connectors in the combiner boxes, and the same applies to their negative counterparts. The aggregate of all these connections (with more than two panels) creates a photovoltaic output circuit.

In sharp contrast to wiring panels in series, wiring in panel enhances the amperage produced by the panels while the voltage remains constant. Using the same scenario as before, stringing four 60-volt panels (with an amp rating of 10 amps) in parallel will create a total voltage of 60 volts and a total amperage of 40 amps. This kind of wiring helps you meet the amperage requirements of your inverter. For instance, if the minimum amperage requirement is 60 amps, you must wire at least six 10-amp panels.

Wiring Solar Panels in Parallel

man wires solar panels

What You Need

  • Identical solar panels (if you can’t get identical panels, at least get panels with similar amp ratings)
  • Y-branch connectors
  • Multimeter

The Wiring Process

  1. Like in the first step with the first wiring method, pinpoint the negative and positive solar cables.
  2. Same as step 3 under wiring solar panels in series.
  3. Once you have easy access to the panels’ wiring, link the solar cables to the Y-branch connectors, the positive wires of two panels should go to the FFM side of the connector, while the negative solar cables should be joined to the MMF side.
  4. If you’re wiring multiple panels in parallel, get the connector that will be compatible with its number. For example, if you want to wire four panels in parallel, purchase a pair of 4-in-1 connectors. The Y-branch connector was compatible only with wiring two panels in parallel. That’s how you wire panels in parallel.
  5. Link the charge controller to the battery.
  6. Then link the panels to the charge controller
  7. Return the panel to its original position.

Which Method is Better?

Well, let’s see. Wiring panels in parallel has one advantage over wiring in series; the whole setup still generates electricity even if one of the panels is faulty. You can’t say the same for wiring in series. However, both methods have obvious disadvantages which complement each other. For wiring in series, you may be unable to meet the amperage requirements of the inverter. On the other hand, you may not meet the voltage requirements of your inverter with parallel wiring. The solution will be to combine both wiring methods for your solar system to meet the amperage and voltage requirements of the inverter.

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