Solar Power Panels or Cells in Parallel Circuits





We have already published an article on this topic with the title Serial Connections in Solar Panels. In this article you can find detailed information and examples of the parallel circuit.

To begin with, you should know what paralleled connections are. In serial connections the voltage increases, whereas in parallel circuits the current value increases. This means that the solar cells of a parallel circuit have the same voltage but a higher current. What is important about the parallel circuit is that both of the solar panels have the same voltage output value; if this wasn't the case then there could be issues with the parallel circuit. We will discuss these below

Apart from a simple battery, using an additional protector on the solar panels will protect both our system and the panels. The main reason for that is that the solar panels not only generate electricity by virtue of its chemical construction, but it also consumes and exerts power.

The Mathematical Structure of Parallel circuits

We would like to give some basic information before a practical trial. First of all, suppose that the voltage of each solar panel generates is (V) and the current is (I), and we have two, identical solar panel cells.

Panel 1;
Output Voltage = 12V
Output Current = 15A

Panel 2;
Output Voltage = 12V
Output Current = 15A

When we shunt each of the solar panels:

Vtotal = V
Itotal = I1 + I2

To open this up;
Vtotal = 12V
Itotal = 30A

we have the above results.

Solar Power Panels in Parallel Circuits

Different Types of Solar Panels in Parallel Circuits

The above formula that we stated mathematically could be applied in a practical sense, but the solar cells have to be identical. How can we connect solar panels, whether identical or not, in parallel circuits?

Identical Solar Panels are Connected:
1.) After you carefully detect the (+) and (-) poles and,
2.) Implement both of the panels with the same angle to the sun and,
3.) Be careful that the solar panels are not be in each other's shadow and,
4.) Select the cable in accordance with the distance between the panels and,
5.) Shunt by connecting the same poles to each other.

The system is ready for use; you can use it by taking the mutual output connected at the top.

Different Solar Panels are Connected:
1.) By checking the output voltage of both of the solar panels.
2.) If they have the same voltage but different current, you can apply the above items.
3.) However, if they have different voltage values, there is not much you can do; you cannot shunt them.

Examples and Photos about Parallel Circuits

We have already said that voltage adaptation is the main rule for parallel circuits. When you have this adaptation, the circuits seen in the images below can be made.

The circuit made by using 2 solar panels
Parallel Circuit with 2 solar panels

The circuit made by using 3 solar panels
Parallel Circuit with 3 solar panels

The circuit made by using 4 solar panels
Parallel Circuit with 4 solar panels

You can connect more solar panels using similar methods but you have to be cautious of the current. If your value is more than 70A, your solar panels and you system could be compromised. For this reason, by using both parallel and series circuits, you can increase both voltage and current simultaneously.

The thing to do in this point is to connect 2 or 4 panels in series and increase the voltage to 24V and 48V. The n shunt the units and increase the current values. Here are some examples:

Common connection with 4 solar cells
Connection with 4 Solar Cells - 2V - 2I
With the connection above, both voltage and current doubles and it becomes 2A and 2V.

Common connection with 6 solar cells
Connection with 6 Solar Cells - 3V - 2I
With the connection above the voltage value triples while current value doubles, becoming 3V and 2A.

With 8 solar panels
Connection with 8 Solar Cells - 2V - 4I
With the connection above the current value is four times higher and the voltage value is twice as high.

With 16 solar panels
Connection with 16 Solar Cells - 4V - 4I
In this connection both the voltage and current values have been increased by four times. These kinds of connections are used frequently. The 2V and 8A results for this connection can be obtained, but as mentioned before a high current is not necessary. We can have 3200W with 16 solar panels.

Advantages and Disadvantages of Parallel Circuits

Advantages:
- It helps control voltage while generating the system.

Disadvantages:
- It can only be used with the same voltage values
- It can cause a high current if there are too many connections.

FAQs

Q: I have 3 solar panels that are of different brands but they have the same voltage value, can I shunt them?
A: If they have the same voltage values then you can connect them.

Q: Is the length of the cable important when connecting the solar cells?
A: The cables should be short enough and have the same length.

Q: I have 3 solar panels, 2 of which have a 6V output and 1 with a 12V output. How can I connect them?
A: The best thing to do is just to connect the 6V panels. If you think that efficiency is not that important, you can also use a series connection for the 6V panels and shunt them to a 12V panel.

Q: What kind of problems will I encounter if I shunted panels with 12V and 18V outputs?
A: If you connect this kind of a circuit, the system would work on the generator whose voltage is lower and the remainder will be lost through heat loss. For this reason the total voltage would be 12V.

Q: Is there any upper limit in a parallel circuit? Can I, for example, connect 40 solar cells?
A: It would not be a problem in theory but in practice there could be problems. First of all, the current would measure at least 400A which would cause an increasing loss on the conveying cables meaning you would need to use thicker cables. In addition to this, you have to make the system connections very carefully. Otherwise you would destroy the whole system.

Q: What is the parallel circuit efficient rate in solar cells?
A: Solar panels are not like standard batteries that have stable outputs. Therefore there will be a little lack of efficiency in any kind of circuits.

Q: I would like to shunt 16 panels in a way that they would be like 8 x 2. How thick a cable will I have to use?
A: If you imagine that each panel is 200W and 24V, the output current of the panels is 8A. With 8 shunts the total current would be 64A. For this reason you should use 20 – 30 mm section cables so that the circuit would remain safe.

Q: Do the panels in the parallel circuit face the same direction?
A: Definitely yes. If the panels faced different directions it would receive sunlight at different angles and this would cause extreme loss levels.

Q: Is a cross-connected connection a problem?
A: A cross-connection can cause short-circuit and therefore will obviously be a problem.

Q: What kind of a problem would arise if a panel in the parallel circuit solar panels fails?
A: It will not have a negative effect on the whole system but the system's total current value would decrease by as much as the failed panel. For this reason the failed panel should be replaced immediately.

This concludes the technical and practical details about this topic. If you have solar panels with different power and structure and you do not know how to connect them you can use this guide.

49 Responses to " Solar Power Panels or Cells in Parallel Circuits "

  1. Steve says:

    I have 5 panels differing wattages, All same voltages with controller into 12 volt batteries. Should i use blocking diodes in every panel to stop leakage to other panels?

  2. Bogdan says:

    I am using Tristar MPPT-60 charge controller with max input voltage 150 V. The system voltage is 24 V. May I connect in serial several panels to make total voltage up to 150 V? I’ve heard in case of using MPPT charger the voltage of solar panels should be 1.5 – 2 times higher than system voltage. Is it true? Thank you.

    • greenenergy says:

      Hi Bogdan,

      If your system voltage is 24V your charge controller input must be 24 – 36V for best effciency. 150V ist critical limit for this controller and dont connect solar panels for the 150V.

      • Bogdan says:

        Thank you very much for the respond. I am asking because in Tristar’s manual it is written that 12 Volt battery bank may be charged even with 48 V nominal off-grid solar arrays. The greater the difference between the Vmp and battery voltage, the greater the current boost. I want to connect to panels in serial to make array voltage up to 70 V. Is it efficient? Or according to your response I should stay with 35.5 max arrays Vmp?

        • greenenergy says:

          Tristar Manuel Says,

          Volts In x Amps In = Volts Out x Amps Out

          For example; If you have 15V battery voltage and 30V, 10A inputs your output will be 15V and 20A so your battery will be charged two times faster than 15V input. But one thing is very important; Every battery has a charging limits. If you charge the batteries under high currents the life of battery will be reduce and your operational cost will be increase. So i suggest you if you have 60A/h battery you should charge this battery with max:10 – 12A so your charging time must be over 5 hours for each battery.

          Example ;

          If you have 12 x (12V, 60A/h) batteries and 9 x (24V, 240W) solar panels

          You can connect batteries 4 x Seiral and 3 x Parallel for 48V, 180A/h
          How can you charge this battery group within 5 hours?
          Total Battery A/h = 180
          max charge current = 180 / max charge time = 180 / 5 = 36 A/h
          Battery bank voltage = 48V and charge current = 36A so output power = input power must be 48 x 36 = 1728 (about 1.800W)
          Now you can give this power with 48V X 36A or 96V x 18A. Pratically 48 is a bit of less and 96 is a bit of high for this battery group. 72V is best option for this solar panels.

          Each solar panel 24V and 10A output. For 72V you can connet 3 serial and 3 parallel. So your solar panell array outpu = 72V and 30A. = 2160W. This is a bit of high for our battery charge power requirements but its acceptable.

          What is the charging time under this power?
          Input power = 2160W
          Output Power = 2160W
          Output Voltage = 48V
          Output Current = 2160 /48 = 45A/h
          Battery group A/h= 180
          Total time = 180/45 = 4 Hours. Your batteries will be charged within 4 hours under max sunlight. I suggest again min charing time must be over 5 hours for the safe battery life.

          • Bogdan says:

            Thank you very much for the explanation. I think it will be very interesting for other people reading this article. However my question was a little bit different. I just didn’t put out my thoughts correctly. I have 500 Ah battery bank and 1480 W of total input power (8 x P=185 W, Vmp=35.16 V, Imp=5.27 A). The system voltage is 24 V. It means that max charging current can be 1480 W/24 V = 61.66 A (according to specification my battery can be safely charged with 83.7 A). Because Tristar’s max current is 60 A so I set max current threshold programmably to 60 A. But I never discharge my battery below 50% therefore usually charging current not exceeds 50 A in case of clear sky in the summer time.

            At this moment all my 8 panels are connected in parallel. The distance to the charge controller is 30 meters. So I have almost 8% voltage drop on my 16 mm2 cable. The idea was to increase input voltage to 70.32 V by connecting two panels in serial and then four pairs in parallel. The input power will be the same – 1480 W and accordingly max output current will stay the same. That was my question. So can I increase voltage in order to decrease voltage drop on my cable?

          • greenenergy says:

            There is a very simple answer to your problem. Yes you must increase the solar array voltage with 2 X Serial + 4 X Parallel for less voltage drops. The output will be Vmp= 70V and Imp = 22A and the voltage drop will be under %8.

            Its about current density, if you load “solar-charger” cable with high current that cable will be create high inductive reactance and that reactance will be increase voltage drops. So i suggest you to use high voltage and low current on the copper cables.

            If you connect the panels with 2 X serial + 4 x Parallel the Imp = 22A the voltage drop values reduced to %2 – 3. Also if you change the cable type with 25mm the voltage drops will go %1 – %2.

  3. Sarah says:

    I have 100w 18v solar panel and 12v 80 amp battery and a 10a controller.

    Can i connect since the volts are different on the solar and controller?

    Thanks

    • greenenergy says:

      Hi Sarah,

      Yes you can connet the charger as solar panel voltage over the battery voltage. Please check the solar charger product manuel for the max inut voltage.

  4. eddy jacobsen says:

    I have seen little about wire dimension and length of them?
    Is there a certain length from the solar to bat bank that SHOULD be done?
    I know if the cables are too thin, the loss is great; but if the cables are more and necessary thick, is that an advantage??
    How is loss calculated in relation to length of cable? – Given that the dimension of is is correct?

    Thanks
    Ed

  5. Peter Nwabueze says:

    I have a 10Kva inverter, 30 24v/200 watts solar panels and 15 12v/200 watts battery and 4 solar charge controller 12-48v and 60 amps. The connection has not been able to give me light the whole day in my house. How should these be connected to make enjoy this form of power supply. The guy who connected this may have faltered somewhere.

  6. Edil Caban says:

    Hi, i purchased a solar kit- (2) 50w photovoltaic panells 30ah controller,100ah battery and 400w inverter for my food truck and have 6-60w daylight bulbs wich are supouse to consume 13w each,26w lcd and a small 120v 0.1A casio register. I start my load in very sunny day from 10am and at 5pm everything shuts off and the controller is set for 9hr. is this normal for the sistem i have,now they are telling me about another panell and battery these are not the calculations they gave me,need somebody to guide me dont know what to do thank you.

  7. Asm Kaikobad says:

    Can I connect 3 series panels(72V) with 2 series panels(48V) in a array junction box?
    my system voltage is 48V and I use MPPT charge controller.

  8. scot says:

    I have 3x12V 160w panel,12V cotek inverter 3000w 220/240V and I want to run my water pump which is rated 220V 370watts. What size of the battery bank should I buy? Do I also need additional panels?

    • greenenergy says:

      Total power = 370 * 5 Hours = 1850 W

      Your battery bank should be minimum 12V 100 Ah x 2 Batteries. Solar panel number is enough for this system.

  9. Bruce Croxford says:

    I have just had a 5kW solar system installed at home. There are 26, 190 watt solar panels in total. There are 3 parallel circuits consisting of 2 x 8 series panels and 1 x 10 series panels. All panels are mounted at same direction & angle. Wouldn’t this wiring configuration create inefficiencies due to the unbalanced parallel circuit voltages?

  10. ian says:

    please help.

    we are building a solar system.

    We have 8 120 watt panel voltage calculation— as it is a 12 volt system, it would make about 5 to 7 amps equal to watts? What is best connection series parallel?.

    We can use 6mm cable from each panel to common–bus bar– then to controller of correct amp–watt panel measurement??? or battery measurement??? to control charge rate?

    Do we use small controllers one for each opanel or do we group them as –example 4×120 watt bank 1–4×120 watt bank 2. this is to a common controller of 80 amp from bus bar?.

    ideas please same as battery 1 large bank or 2 banks each bank with have enough amps storage capacity– then we can rotate use by charge cycle over 48 hour period or use generator charging on off system battery bank on boost charge.next idea– do we make a solar panel array as a boost charger use one battery bank have a switched system to introduce a 4 panel extra boost for a timed period? do we manual regulate this charge without a controller– or can we use auto dual battery system?..

    Question should we use a seperate refrigerator 240 volt inverter power circuit on seperate battery bank seperate inverter? and power all the on off power lights on its own system this will allow me to have fridge on a safe power source? If we keep volts at 12 amps low we can buy more affordable wires controllers etc– and can add more panels and batteries if necessary. i low lots of going around in circles but it is not getting into to much high costed controllers with lots issues from electrical power theories?.

    please set me straight if i have lost the plot, regards ian

    regards ian

  11. Kenny says:

    I accidentally hit submit before finishing! Here is the compile comment.

    I have 7 240 watt solar panels. These have a 38V open circuit voltage and a current of about 8.6. My battery bank is set for 24V. Can I connect these in parallel? Since I am using an Outback PowerFlex Controller and a PV combiner I could add a few panels in series but due to the odd number of panels I rather connect these in parallel to have each string coming to the combiner the with the same voltage of +/- 38V (strings of of one panel each). Is this feasible?

    If you wonder why 7, these is the area I can utilize for a trailer I am converting.

    Thanks in advance.

    Kenny

  12. Graeme Martin says:

    Could you show me a diagram of how to connect 6 modules in a string and 4 strings in parallel.

  13. kamran says:

    Hello Dear,

    I wants to connect 3 batteries which are connected in series to 6 solar panels , because i wants to charge each battery (12v/85amp) with 12 volt and 8amperes. should I make 3 modules of 2 solar panels for each battery individually? with 1 one controller circuit or 2 controller circuit for 1 module of 12v 8amperes?

  14. john says:

    Hi I have 3 100w and one 50w how can I connect them to have 12v and how much amps i will have.

    Keep up the good work kind regards john

  15. sundari says:

    Hello sir,

    Could you please tell me how many solar panels i need to connect to get 17000 kW output from solar panel,what is the mppt charge controller and battery rating i need to design?

  16. Dr Elias FOMUNGUM says:

    I have two 10 watts Solar Panels and I wish to power 4 DC-bulbs of 5 watts each and also to be charging mobile or cell phones. What are the other components needed? Can you please send me a diagram on how to do the network connection?

  17. Swamy says:

    i ve 1kv /24volts inverter and three 100 watt panels, two 100amp battries, i connected batteries in series,and i done d same with panels, immedately battries are starts dicharging, pls guide me how can i connect my panela as well as battries

  18. Naqib says:

    Dear sir
    How to connect teen 12v solar panel for the 96v sistem pls advice me.

  19. prem says:

    I have a question in mind from long ..
    I have a 12v, 10ah , battery and i want to charge it with 1. 12 volts panel with 1amp
    2. 24 volts solar panel with 1amp current limit ,

    (since 24 volts will give about 15 volts even in dim light , i can be able to charge with 24 volts with current limit .
    so can i use higher voltage solar panels with a current limit LM317 ic ???

  20. ali says:

    I have two solar panel and connected them parallel. Voltage are still same which is good but i am getting the same amps too isnt it amps should be high both panel work i checked them one by one both are giving 19 volt and 7.28 amps single or connected.

  21. Dave says:

    Good day, i have a 48v xth8000 studer inverter. 8x 200ah deep cycle AGM Omnipoer batteries. 8x 250w panels in one bank and 14x 240 watt panels in another bank. With 2 different charge controllers. How can i connect the 2 solar arays? Must my input voltage be doubled to 96v. Because at this stage, each panel aray is connected for 48v, but something damaged my batteries, because it doe not last.

  22. Bilal says:

    I have 2 x 250w solar panels connected in parallel using mc4 Y connectors. In theory the total amperes should be the sum of amperes from each panel. However I am not getting that. For example each of my panels were producing 3.5 amps so the total should be 7amps. But I was only getting about 3.8 amps. Are there any losses in the Y connector? or are there any other reasons?

  23. Ram says:

    Can 5 nos 200wp,24v panel and 4 nos 250wp,24v Panel be connected to get 2KWp output

  24. nadeem says:

    I have use two solar panel 22vdc\150watt of each panel i connected in parallel but 12v battery is not charged what reason of this

  25. Mal says:

    I have 2 solar banks 3x125w 12v, in series and parallel to 36v. This goes through an mppt regulator
    to 24v batterys . My question is if a shadow moves across one panel does it wipe out
    that whole series bank of 3x125w 12v panels?
    Regards Mal

  26. Jason Arket says:

    I have 6 solar panels ranging from 18-24 volts and 1 amp each. In parallel, how much power do I have going into the charge controller. Please forget all other considerations and give me the equation for that scenario. Thanks! -J

  27. mudassir says:

    my question is that,i have 4 panel,s of 150watt,s.when i chek single panle in sun light each panels give 8Amp but when i connect 4 panels 1n perallel they give 21AMp .plz tell me about this why thy r current decrease
    each panel= 8 amp
    4panels *8= 32 Amp
    but it gives 21 amp

  28. yogi says:

    With 16 solar panels, can you show an image to get a 2V, 8I.

    Thanks,
    Yogi

  29. NARAYANAN.S says:

    Hi,

    I am having one solar system with 10 nos. of 95Wp module at 12V Nominal each and another system with 12 nos. of 80Wp modules at 12V Nominal each.Currently i am using 1 KW inverter for each system at 24V DC nominal.
    Now i wish to combine the two system in to single system with 2 KW inverter at 48V DC nominal. I request you to provide the technical combination for the same and also i request you to provide whether we need to provide any diodes in the combination network.

    Expecting your kind reply at the earliest to this mail id at the earliest.
    The matter is most urgent.

    Thanks.
    S.Narayanan.

  30. Barrack Otieno says:

    I have 16 solar panels of 225 watts 24volts and i want to connect them to 12 200Ah battries in a 24volts battery bank system. which is the best connection i can have to have maximum voltage & current?

  31. Babs says:

    Hi, Please I have a 6000w 48v inverter, 8 pieces 6v 410 troan batteries. A 150vdc 96amps mppt charge controller, 24 pieces 100watts panel and 6 pieces 130watts mono panels. My load rating is 2500watts. How do l configure the solar panels. which is the best connection i can have to have maximum voltage & current? installing in Nigeria. Thanks

  32. Ron says:

    I am putting together a system for personal devices and want to check something with you. I am allowing for two solar array sources rated between 18 and 24 volts each. I wish to increase the amperage so I am building two individual voltage regulator circuits with 18 volt outputs, one for each of the two arrays. I am hoping to connect the output of the two regulators in parallel to get a stable 18 volts with a combined amperage that would not (theoretically) reach the limit of the individual regulators. Will this system work if the arrays are not ‘always’ the exact same voltage, but within the limits for the regulators?
    Ron in Calgary Canada

  33. Ron says:

    In addition to my recently posted comment …… I should add that I am figuring on isolating the output of the two regulator circuits (before connecting in parallel) by using diodes so they are not feeding back into the other one, sort of thing.

    Ron in Calgary Canada ….again and Thanks! :)

  34. ghil says:

    Hi , im from philippines..im planning to go for solar energy but i dont have enough knowledge to do this.. I want to run my 75watts fan and 23watts bulb for 10 hours a day.. im planning to buy a two 100w panel and 12v 100ah battery..what should be the inverter watts , charge controllers amp , size of wires and breakers?!

    Should i put breakers between panels and charge control and another breaker between charge control and battery another breaker between battery and inverter?!
    Thank you very much and hope you can help me..
    More power..

  35. Kamran says:

    Hello,
    please suggest series and parallel combination of my 9 solar panels each having Vmax=30.9, Imax=8A, having 5kva inverter, and 4 x 200 AH batteries.
    currently, 3 in series and then three parallel groups are connected making Vmax=93V, and Imax=24A. is this configuration ok?

  36. K.Nagarajan says:

    Dear Sir/Madam

    I have 11 solar panels, 7 of which have a 12V 150 W peak output and 4 with a 36V 240 w peak output. How can I connect 3kw 48 v PCU?

    I am awaiting for your reply Thank you

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