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Connecting Solar Panels Together for Increased Power Article 30/06/2022
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Connecting Solar Panels Together

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 photovoltaic panels can be electrically connected together in series to increase the voltage output, or they can be connected together in parallel to increase the output amperage. Solar pv panels can also be wired together in both series and parallel combinations to increase both the output voltage and current to produce a higher wattage array.

Whether you are connecting two or more solar panels, 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 Together in Series

The first method we will look at for connecting solar panels together is what’s known as “Series Wiring“. The electrical connection of solar panels in series increases the total system ouput voltage. Series connected solar panels 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 from above, we can see that when these pv panels are connected together in series, the array will produce an ouput voltage of 18 Volts (6 + 6 + 6) at 3.0 Amperes, giving 54 Watts (volts x amps) at full sun.

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 output amperage will remain the same as before 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 Ampere. Then the array will produce 19 Volts (3 + 7 + 9) at 1.0 Ampere 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 Together 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. For parallel connected solar 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 output voltage still remains at the same value of 6 volts, but the total amperage has now increased to 9.0 Amperes (3 + 3 + 3), producing 54 watts at full sun.

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

connecting solar panels together

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 Summary

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 off-grid photovoltaic solar electric systems in your home.

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475 Comments already about “Connecting Solar Panels Together

  • Hi,
    I have 8 x 250W panels, where 2 each are connected in series and the 4 sets of series connected in parallel. They are connected to a 60A, 48V charge controller (PWM) and 4 x 12V batteries in series. However, using my meter, i have never gotten an output from the panel of more than 4.5Amps. Is this normal, what could the problem be? I live in a very sunny country. Thanks

    • As explained many times here, just because your panels are rated at 250W does not mean they will supply 250W continuously. They will supply the amount of power required by the connected load. Elecrically empty the batteries and then see what the current value is when they have to charge discharged batteries.

  • Hi can I mix battery bank ampere, scenario have 2x 120w panels in series, and 4x 12v batteries in series 48v system ranging from 100, 102 to 105amps each with a 30amp mppt solar charger. When I connect all 4 batteries to the charge controller the charge control goes to Ovl and then Off and never charge , but if I disconnect batteries and leave only one connected it charges okay. ?? Is do we need more solar panels to charge all 4 batteries or is the different amps on battery a concern?? Or can we add 3 more 120w panels?

    • Obviously Ovl means “overload” and your controller is automatically switching off for safety reasons. Check the ratings of your charge controller.

  • Hello
    I have 24 solar panels 250W each which I want to connect to 48V Victron inverter and battery bank. What is the most efficient way to connect solar panels to achieve 48V?

      • This is incorrect, 250w panels would give around 30v each, so that would be 2x30v in series =60v x12 in parallel.

        • As always, limited information is supplied as only the wattage size is given, so a12 volt panel output is assumed. To give a Vmp of around 30V, a 60 cell, 24 volt panel is required which is I guess what you have assumed.

  • Great Site!
    So, I have 18 panels, about 340 VDC and an inverter that has a minimum 150 VDC input. Would I get more output if I split them up into two 9 panel parallel strings?

    Many thanks

    Rob

  • Hello,

    Great information here. I am doing a solar install on my sailboat. I have the following:
    * One 120 Watt, 18 Volt, 6.66 amp
 Panels
    * Four 100 Watt, 17.7 volts, 5.7 amp Panels
    My plan is to install all 5 in parallel but I’m now rethinking this based on the information provided here. I think I should wire the 4 identical panels in parallel. I would then wire the 120, 18 volt panel on its own. My question is do I run them all to the same controller, perhaps meeting at a bus bar that then goes to the controller? Or…should I purchase a separate smaller controller for the 129 watt panel and run two controllers to the battery?

    Note – I’ve purchases a Victorn 100/50 MPPT controller which is more than enough to handle all of the above. My boat has a 12 volt house batter bank.

    Thanks much for any advice you can offer.

    Ed L

    • It would be a smart move to connect the four 100 watt panels together in series, as they are identical panels. In parallel currents add, voltage is the same so you can use parallel connection to boost current output. Connecting two charge controllers to the same battery bank is not a good idea as the two controllers will compete against each other to charge the batteries.

      Then what to do with the fifth pv panel. In parallel, currents add but voltage mismatch is more drastic. At low irradiance this generally not a problem but at full sun the voltage output will be reduced slightly as the lower voltage panels stop generating power and now dissipates it being controlled by the larger panel. However, for your five panels the mismatch is minimal, so the power loss at full sun only will also be minimal, so connect them all in parallel.

  • Hi,

    A solar panel is build up with many cells combining in serial method. Attaching another panel is more similar to expanding the size of one panel with higher voltage… So lowest amp is the current in one cell.. then, is the current (amperage) depend on one cell ?

    I have many panels with different specs and going to buy a hybrid charging controller (GW5048D-ES ) since I have 1 KA battery bank. MPPT charging voltage is 125~550 in according to its spec…
    01). is it loosing efficiency by connecting panels in serial ?
    02). When connecting in serial, higher voltage is passing through the panel set and is the strength of tabbing wire is enough to increase such a voltage?

    Thank you

    • As explained in the tutorial, solar panels in series increase the total voltage for a given current, so if five 12 volt panels are connected in series then the total voltage output will be 60V ( 5 x 12V), but the voltage across each panel will still be only 12V. The size of the tabbing wire as you call it depends on the load current and its length (DC voltage drop). Solar cell efficiency depends on many factors and not whether they are connected in series or parallel.

  • 24v system. I got 6 260w 24v panels, connected parallel, 4 12v 120A batteries deep cycle connected parallel give 24v.Question is it enough power for 6 x5w led lights and 120w TV for 4 hours per day night time

  • I have four Renogy 100W polycrystaline panels, two are wired in series, the other two wired in series and then the two sets connected in parallel. I am using 10ga wire ,the panels are 25 ft from 60amp MPPT charge controller (12v output) going into 4 x 6v golf cart batteries, today on July 5th full sun no clouds in Ma. I have 28 volts, 5 amps and 145 watts, shouldn’t i have more output?

    • Just because you have 400W installed does not mean the panels will supply 400W continuously, they will supply the amount of power required by the load up to a maximum of 400W. Your charge controller will dictate what’s needed.

  • What type of connectors will I need to add 2 more 100watt panels to my already installed 2 100watt panels. Currently I have 200 watts into a 30 amp mppt charge controller ( in parallel) with 2 125amp Vmax SLR deep cells, I will be adding a third batt.
    Thank you

  • Hi sir

    I have a 10 000w/48v invector /charger using 4x 12v betteries.

    The question is it possible to use the same power that has been produced by this inveter to power up a charger on it and how should be the connection

  • This is my thought I don’t live in a sunny climate and figure the panels won’t get full sun . So if it is cloudy all the time the panels may only put out half the voltage if I put them in series I would get the 12 -14 volts needed to charge the batteries even if they only put out half the voltage each. Does this sound reasonable ?
    Have 2 100 w panels to charge 12 volt battery for camper in not so sunny Vancouver.

    • Solar panels give out their maximum wattage at full sun, but can also produce an output during daylight hours at reduced solar levels. For example, 100 W (PV panel) exposed to 1 hour of full sun (1000 Wh/m2) equals 100 Wh of electricity, whereas a panel exposed to half sun (500 Wh/m2) for 2 hours would also produce 100 Wh of electricity.

      The other advantage of cloudy or overcast conditions is that photovoltaic panels can convert the sunlight into electricity more efficiently at lower temperatures, so your reduction may not be too great.

  • I have 3 250w solar panel collected in parallel with 30a charger controller with 2 battery 12v in parallel and given me 24.9v 17.5a it is ok

  • i have two 150 watt 12 volts solar panels and on chagre controller charging through solar panel is 2.0 amp is this normal?

  • Sir I have 4 panels of 150 amp 12 v and two 240 amp batteries I connected two panels ( positive to positive and neg to beg ) to one battery is this the correct way or should I connect them all together in series or parallal way to get more power?
    Regards

    • I have 22 SP Each are 28.9 V (because they measure 30v) 8.2 Amp & 240 Watts What di you suggest for usage & whatcontroller do you suggest

  • hi im looking at doing 190w panels series (2 x 36.6v= 73.2) then in parallel of 6 at 5.5 amps. do i need to worry about the amps being to high? setting up 48v system to 240v .

  • Sir
    i have 2 solar panels rated 17. 90V, 8.40A connected parraller.
    My question is how much output it will give me on fully bright sun

  • I am hooking up solar for camp. I have (2) 216w, 9.3a, 23v solar panels. I am running them through a 30a charge controller to (2) 12v batteries in parallel. Is it best to hook the panels in series or parallel?

    Thanks,
    Forrest

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