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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.


46 Comments » for Connecting Solar Panels Together
  1. Patrick Adotey Patrick Adotey says:

    Please how to connect my 36panels 320w. 4panels in series and 9 strings in parallel. Thanks

  2. Jr Jr says:

    Thank you very much for this information.I have read a lesent something important.I had a question though. I have one solar panel 153Watts that I am currently using to charge two 150 amp batteries that are connected in parallel. I recently bought another panel that is 153 wats. What’s is the best way to conect it with the other panel? Series or parallel and considering that my batteries are already connested in parallel would that make a difference?

    • The inter-connection of your solar panels would depend on the characteristics of your battery charge controller, series panels would give you a higher voltage, while parallel panels would give you a higher charging current.

  3. Felipe Olivares Felipe Olivares says:

    What would be the optimal serial/parallel panel arrangement to address what I believe is a shading issue?

    I recently installed an interconnected-to-the-grid solar array and am noticing a significant drop in the harvested kWh.

    So this is what I have: 10 (Ten) 250-watt solar panels (open circuit voltage rated at 35 volts; all of them wired as a single serial string) 1 ThinkPower 2200 watt central inverter with max input of 13 amps and 500 volts, 1 MMP tracker

    So I had everything installed in September (I’m in the northern hemisphere); during the first days/weeks I was generating as much as 14-15 kWh per day. As year has passed I’m currently generating 5-8 kWh per day. At this rate, I’d be surprised if I’m generating more than 2-4 kWh per day at the peak of the winter.

    Here’s another piece of information that’s important: two of the panels are shaded. When the panels were installed the shading was minimum if any, but as we get closer to the winter I’m thinking the shading could be as much as 40% of these two panels during noon time.

    I was wondering if I by re-arranging the panels into several series in parallel I could isolate/optimize the array so as to minimize the degrading effect of the shading.

    Perhaps I could split my single string into two 5-panel serial strings connected in parallel hopes I may isolate the shaded two panels? Perhaps I should remove the two shaded panels altogether and stay with a serial string of 8 panels? Removing the source of the shading is not feasible (refer to this image: http://oi68.tinypic.com/eg3h8w.jpg

    Input greatly appreciated.

    Thanks.

  4. will basham will basham says:

    This a tech Battery Query! I have a charger/inverter all on a batt.box-80Ah! Have since secured from same vendor another 80Ah batt in an effort for longer power intervals of med. Equip. Am wanting to again expand to another batt. not from Vendor(excessive expense) Would it be detrimental to my system to olace a 100 Ah batt. in the array? Would the 100Ah ever become fully charged as do the other two from the attached solar panels(2-100watt)?
    Thanks a bunch for any aid you can send this old retired cripple! W. Basham

    • It depends on how you connect the batteries. In a series configuration the 100Ah will only charge to 80Ah. This is because as the 80Ah battery reaches its fully charged state the charging current which is common to ALL batteries in a series chain reduces to a very small trickle charge and is insufficient to full charge the 100Ah battery. In a parallel configuration however, both the 80Ah and the 100Ah batteries will charge fully. Connecting Batteries Together

  5. Irv Irv says:

    In lieu of using a heavier gauge wire from my panels to my controller, I intend to use all 3 wires in a 14 gauge cord for the positive connection and all 3 in a 2nd length for the negative connection. Is this beneficial even though the 3 wires in each length are insulated from each other?

    • Doubling or trebling up of cables to carry greater currents is ok as long as they are the same diameter (gauge) and correctly terminated together at each end, whether in a single crimp connector or individually bolted together. The fact that they are individually insulated does not matter. But remember that 3 cables will carry one third of the current each, but if one cable fails the remaining two will have to carry half the current each which may exceed their rating. Also cables used for solar panels are usually double insulated to protect from mechanical damage, sun and weather exposure.

  6. kudakwashe kudakwashe says:

    i have 2*70watts solar panels and a 250 watts solar panel, which charge a 12v 200Ah battery. which solar configuration will give me the shortest time to charge the battery

  7. Virendra Virendra says:

    Hello. Can same solar panel be used for water pumping and electricity generation together

  8. Emmanuel chibamba Emmanuel chibamba says:

    Sir
    I have learned a lot .
    I can now connect my 3 batterys in parallel to 2 solar panels .
    Now this batterys are car batterys 120 h each, is it ok ?

  9. Amos Amos says:

    One more question.Between Amperage and Voltage,Which one charges batteries?I was taking a look at my control unit and realized that on a rainy day the voltage coming in is 12 but 0 Amps.can a battery charge in such a scenario?Thank you

    • Current in amps charges batteries as they convert the electrical energy into chemical energy.

      • Amos Amos says:

        Thank you.I decided to connect my three batteries in parallel but then I have set up my two solar panels (120W and 200W) in a way that each is on its own.The first panel (200W) is connected to 15A charge controller while the other one (120W) is connected to a 5A Charge controller and both the outputs from the two charge controllers have been connected to the batteries.is the connection harmful to the batterries in any way?

  10. Amos Amos says:

    Hi, I have two solar panels (120W and 200W) and three 12v100a batteries,two charge control units-24v and 12v.what is the best connection that will charge my batteries fully at the same time?If I connected the panels in series but put the one with a higher output in front will the power drop?Thank you

    • You only have two panels, so series = 24V and parallel = 12V. (assuming 12V panels, as not stated)
      3 batteries in series = 36V which is too high, 3 batteries in parallel = 12V.
      Then a 12V system is required to charge all three batteries at the same time.

  11. Phil Phil says:

    I have two (2) 60w x 3.33A /w/ charge controller (suitcase type) – and two (2) 50w x 2.78A with charge controller (another suitcase type). Do I connect them in series or parallel? My thought is “series”.

    I drew myself a schematic of what I think. All my solar panels are rated @ 12volts so the voltage remains the same. Correct? And amp ratings differ but I add those together to get a total amperage rating. Correct?

    And amp ratings on the all panels are 3.33A each x 2 – and 2.78A each x 2. That gives me a total (added together) amperage rating of 12.2Amps.

    Are my calculations correct or wrong if wired in “series”?

    • With your 4 panels (2 x 12V, 3.33A and 2 x 12V, 2.78A) conected in “series”, the total voltage will be 48V (4 x 12) at 2.78A, as this is the lowest amperage.

      With your 4 panels connected in “parallel”, the voltage will be 12V, but the amperage will be 12.2A (3.33 + 3.33 + 2.78 + 2.78).

  12. Dallas Mories Dallas Mories says:

    I HAVE A 140 WATT MOUNT ON THE TOP OF MY R.V… I WANT TO GET A 200 WATT FREE STANDING, WITH A 15 AMP BATT CONTROLLER ON IT (SUIT CASE TYPE) . COMES WITH BATT CLAMPS CAN I HOOK IT TO THE BATTERIES.. 4 – 6 VOLT TIED IN TOGETHER. WITHOUT DAMAGE TO THE BATTERIES OR THE 140.. IF NOT WHAT DO I NEED TO DO… THANKS FOR YOUR TIME & HELP..

    • Yes you can feed both panels into your battery bank providing you connect the positive and negative terminals correctly, and your 140W RV panel is also regulated by a charge controller. This will protect the battery bank against excessive charging.

  13. Anwar Anwar says:

    Sir
    I have two solar panels of 150 watts and battery of 12 v 100 amp.i want to charge my battery as soon as possible what method i will adopt i.e serious or parallel….

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