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Connecting Solar Panels Together





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How to Connect Solar Panels Together

solar powerConnecting solar panels together is a simple and effective way of increasing your solar power capabilities. Going green is a great idea, and as the sun is our ultimate power source, it makes sense to utilize this energy to power our homes. As solar power becomes more accessible, more and more homeowners are buying photovoltaic solar panels.

However, these photovoltaic solar panels can be very costly so buying them over time helps to spread the cost. But the problem then becomes how do we connect these extra solar panels together to increase the voltage and power output of what’s already there.

The trick here when connecting solar panels together is to choose a connection method that is going to give you the most energy efficient configuration for your particular requirements. Connecting solar panels together can seem like a daunting task when you first start to look at how it should be done, but connecting multiple solar panels together is not that hard with a little thought. Wiring solar panels together in either parallel or series combinations to make larger arrays is an often overlooked, yet completely essential part of any well designed solar power system.

There are three basic but very different ways of connecting solar panels together and each connection method is designed for a specific purpose. For example, to produce more output voltage or to produce more current. Solar panels can be wired in a series or parallel combination to increase the voltage or amperage respectively, or they can be wired together in both series and parallel to increase both the voltage and current output producing a higher wattage array.

Whether you are connecting two solar panels more more, as long as you understand the basic principles of how connecting multiple solar panels together increases power and how each of these wiring methods works, you can easily decide on how to wire your own panels together. After all connecting solar panels together correctly can greatly improve the efficiency of your solar system.

Connecting Solar Panels in Series

The first method we will look at for connecting solar panels together is what’s known as “Series Wiring“. Connecting solar panels together in series is used to increase the total system voltage. Solar panels in series are generally used when you have a grid connected inverter or charge controller that requires 24 volts or more. To series wire the panels together you connect the positive terminal to the negative terminal of each panel until you are left with a single positive and negative connection.

Solar panels in series add up or sum the voltages produced by each individual panel, giving the total output voltage of the array as shown.

Solar Panels in Series of Same Characteristics

connecting solar panels together in series

 

In this method ALL the solar panels are of the same type and power rating. The total voltage output becomes the sum of the voltage output of each panel. Using the same three 6 volt, 3.0 amp panels as above, we can see that when they are connected together in series, the array produces 18 volts (6 + 6 + 6) at 3.0 amps, or 54 watts (volts x amps).

Now lets look at connecting solar panels in series with different nominal voltages but with identical current ratings.

Solar Panels in Series of Different Voltages

solar panels in series with different voltages

 

In this method all the solar panels are of different types and power rating but have a common current rating. When they are connected together in series, the array produces 21 volts at 3.0 amps, or 63 watts. Again the amperage remains the same at 3.0 amps but the voltage output jumps to 21 volts (5 + 7 + 9) .

Finally, lets look at connecting solar panels in series with completely different nominal voltages and different current ratings.

Solar Panels in Series of Different Currents

solar panels in series with different currents

 

In this method all the solar panels are of different types and power rating. The individual panel voltages will add together as before, but this time the amperage will be limited to the value of the lowest panel in the series string, in this case 1 amp. Then the array will produce 19 volts (3 + 7 + 9) at 1.0 amp only, or only 19 watts out of a possible 69 watts available reducing the arrays efficiency.

We can see that the solar panel rated at 9 volts, 5 amps, will only use one fifth or 20% of its maximum current potential reducing its efficiency and wasting money on the purchase of this solar panel. Connecting solar panels in series with different current ratings should only be used provisionally, as the solar panel with the lowest rated current determines the current output of the whole array.

Connecting Solar Panels in Parallel

The next method we will look at of connecting solar panels together is what’s known as “Parallel Wiring“. Connecting solar panels together in parallel is used to boost the total system current and is the reverse of the series connection. By parallel wiring panels you connect all the positive terminals together (positive to positive) and all of the negative terminals together (negative to negative) until you are left with a single positive and negative connection to attach to your regulator and batteries.

When you connect solar panels together in parallel, the total voltage output remains the same as it would for a single panel, but the output current becomes the sum of the output of each panel as shown.

Solar Panels in Parallel of Same Characteristics

connecting solar panels together in parallel

 

In this method ALL the solar panels are of the same type and power rating. Using the same three 6 volt, 3.0 amp panels as above, the total output of the panels, when connected together in parallel, the voltage output would remain the same at 6 volts, but the amperage would increase to 9.0 amps (3 + 3 + 3), or 54 watts.

But what if our newly acquired solar panels are non-identical, how will this affect the other panels. We have seen that the currents add together, so no real problem there, just as long as the panel voltages are the same and the output voltage remains constant. Lets look at connecting solar panels in parallel with different nominal voltages and different current ratings.

Solar Panels in Parallel with Different Voltages and Currents

solar panels in parallel with different voltages and currents

 

Here the parallel currents add up as before but the voltage adjusts to the lowest value, in this case 3 volts. Solar panels must have the same output voltage to be useful in parallel. If one panel has a higher voltage it will supply the load current to the degree that its output voltage drops to that of the lower voltage panel.

We can see that the solar panel rated at 9 volts, 5 amps, will only operate at a maximum voltage of 3 volts as its operation is being influenced by the smaller panel, reducing its efficiency and wasting money on the purchase of this higher power solar panel. Connecting solar panels in parallel with different voltage ratings is not recommended as the solar panel with the lowest rated voltage determines the voltage output of the whole array.

Then when connecting solar panels together in parallel it is important that they ALL have the same nominal voltage value, but it is not necessary that they have the same ampere value.

Connecting solar panels together to form bigger arrays is not all that complicated. How many series or parallel strings of panels you make up per array depends on what amount of voltage and current you are aiming for. If you are designing a 12 volt battery charging system than parallel wiring is perfect. If you are looking at a higher voltage grid connected system, than you’re probably going to want to go with a series or series-parallel combination depending on the number of solar panels you have.

But for a simple reference in regards to how to connect solar panels together in either parallel or series wiring configurations, just remember that parallel wiring = more amperes, and series wiring = more voltage, and with the right type and combination of solar panels you can power just about any electrical device you may have in your home.

For more information about Connecting Solar Panels Together in either series or parallel combinations, or to obtain more information about the different types of solar panels available, or to explore the advantages and disadvantages of using solar power in your home, then Click Here to order your copy from Amazon today and learn more about designing, wiring and installing photovoltaic solar electric systems in your home.

Some high quality solar panels you may be interested in which can be connected together and used in solar arrays.


66 Comments » for Connecting Solar Panels Together
  1. Awais Awais says:

    hello administrarot.!
    i have 4 -250watts panel and i wired them in series and also i have 2 -200 Ah battries which are also wired in series and having 24 volt inverter of 3kv . so my question is that in how much time it takes to charge my battries?
    thanks in advance

  2. Dave McCampbell Dave McCampbell says:

    Thanks for your excellent article on wiring solar panels. A friend and I are discussing what happens with like 24v nominal panels wired in parallel or series with an MPPT controller if one panel’s output is seriously degraded by shading. My understanding is that if wired in series current output of all panels will be reduced to that of the shaded panel. If in parallel only shaded panel’s current output will be reduced. Therefore if shading on one or more panels might be a problem best to wire in parallel. Can you confirm or not?

    • Shading, either partial or full, can greatly reduce the power output of a solar panel, and in severe cases can run the risk of hot spot formation. A photovoltaic cell in the dark behaves as a diode under forward bias acting as a short circuit.

      If connected in a series configuration, the good cells bias the shaded cell so large amounts of power is dumped into the shaded cell as shaded cells do not add to the power produced, but they absorb it. A bypass diode across the photovoltaic cell limits the voltage across it when shaded, but any bypass diodes must be rated to take total possible series current.

      Parallel shaded cells, when connected directly to a battery, will provide a short circuit discharge path for the battery. This high reverse current can be stopped by the use of a blocking diode. Blocking diodes also prevent back charging of the battery at night as the diode prevents charge coming back from the battery to the cell, or panel.

      Then if the solar panel, or array is protected by both bypass and blocking diodes, any shading will have minimal efficiency loss whatever the configuration.

  3. Vikram sharma Vikram sharma says:

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  4. Don Don says:

    Hi, what would work better in charging batteries in my RV 3-100 watt panels or 1-300 watt panel?

  5. Abdullah Shahab Abdullah Shahab says:

    I have installed three each 12v 150w 10amp solar panels. This should be 12v 450w 30amps. But the max amps i get to charge batteries at peek hours (15v while connected to batteries) is 12.5amps. this equals 12.5A×15v=187watts. Why I am not getting 450watts of power?

    • There could be a number of factors why you are not seeing full power, the panels are not receiving full sun, they maybe badly aligned, sun strength is low, or your batteries are only drawing the amount of power they required to charge. Just because your array has a potential maximum power of 450W, does not mean it will deliver 450W continuously.

  6. hassan hassan says:

    If I connect solar panel of the same volt and amp in series to a bty of two 12 volt also connected in series,what ll happen to my eqpt

  7. nilesh nilesh says:

    connecting solar panels in series or parallel increases the voltage or current respectively but do the panel embedded wiring with mc4 connectors bears the increased voltage or current? say for some 50 or 100 solar panels are connected in a combination of series or parallel?

  8. Bradford Young Bradford Young says:

    I have wired 4 small solar panels, Voltage: 5V Current: 160mA, in parallel but the amps have not gone up. Help

  9. Vincent Luringan Vincent Luringan says:

    Hi , I am an electrician by profession and running a small electrical contract here in Kokopo,East New Britain Province, Papua New Guinea.
    My focus now is to really know inside out of these solar systems and all its features including all its calculations .

  10. Troy Troy says:

    I have 2 solar panels one 80 watts =17.5 V =4.571 A and the another solar panel that is 160 W =18.73 volts =8.62 A I plan on wearing them in parallel, as I believe that is my best choice correct.. which will give me 13.191 amps but will only have 17.5 volts and these will be wired to a 12 volt 30 amp /400 watt max PWM charge controller, I guess my question is losing that 1.23 volts, would it be a great loss when charging my two 6 V batteries I have in the series which is giving me 12 V to my RV thank you.

    • No, your charge controller will control the 12 volt charge to your batteries. The values you have quoted are maximum open-circuit voltage (Voc) and short-circuited current (Isc) values which will not occur if they are connected to the charge controller.

      • Troy Troy says:

        Actually no, I quoted the (Vmp) maximum power voltage and (Imp) Maximum power current. But anyways I should be fine then you think with putting a 160 watt solar panel in parallel with an 80 W solar panel? Thank you!

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