## How to Make a Solar Inverter Circuit

Solar power is abundantly available to us and is free to use, moreover it’s an unlimited, unending natural source of energy, easily accessible to all of us.
We have discussed how to use solar panels for generating electricity from solar or sun power, in this article we are going to discuss a simple arrangement which will enable us to use solar energy for operating our household appliances.

A solar panel is able to convert sun rays into direct current at lower potential levels. For example a solar panel may be specified for delivering 36 volts at 8 amps under optimal conditions, but we cannot use this magnitude of power for operating our domestic appliances, because these appliances can work only at mains potentials or at voltages in the ranges of 120 to 230 V. Further more the current should be an AC and not DC as normally received from a solar panel.

We have come across a number of inverter circuits posted in this blog and we have studied how they work.

Inverters are used for converting and stepping up low voltage battery power to high voltage AC mains levels.

Therefore inverters can be effectively used for converting the DC from a solar panel into mains outputs that would suitably power our domestic equipment.

Basically in inverters, the conversion from a low potential to a stepped up high mains level becomes feasible because of the high current that’s normally available from the DC inputs such as a battery or a solar panel. The overall wattage remains the same.

For example if we supply an input of 36 volts @ 8 amps to an inverter and get an output of 220 V @ 1.2 Amps would mean that we just modified an input power of 36 × 8 = 288 watts into 220 × 1.2 = 264 watts. Therefore we can see that it’s no magic, just modifications of the respective parameters.

If the solar panel is able to generate enough current and voltage, its output may be used for directly operating an inverter and the connected household appliances and also simultaneously for charging a battery.

The charged battery may be used for powering the loads via the inverter, during night times when solar energy is not present.

However if the solar panel is smaller in size and unable to generate sufficient power, it may be used just for charging the battery, and becomes useful for operating the inverter only after sunset.

Referring to the circuit diagram, we are able to witness a simple set up using a solar panel, an inverter and a battery. The three units are connected through a solar regulator circuit that distributes the power to the respective units after appropriate regulations of the received power from the solar panel.

Assuming the voltage to be 36 and the current to be 10 amps from the solar panel, the inverter is selected with an input operating voltage of 24 volts @ 6 amps, providing a total power of about 120 watts.

A fraction of the solar panels amp which amounts to about 3 amps is spared for charging a battery, intended to be used after sunset.

We also assume that the solar panel is mounted over a solar tracker so that it is able to deliver the specified requirements as long as the sun is visible over the skies.

The input power of 36 volts is applied to the input of a regulator which trims it down to 24 volts.

The load connected to the output of the inverter is selected such that it does not force the inverter more than 6 amps from the solar panel. From the remaining 4 amps, 2 amps is supplied to the battery for charging it.

The remaining 2 amps are not used for the sake of maintaining better efficiency of the whole system.

The circuits are all those which have been already discussed in my blogs, we can see how these are intelligently configured to each other for implementing the required operations.

A MINI solar inverter circuit with relay changeover is discussed HERE

For Charging Batteries up to 250 AH

The charger section in the above circuit may be suitably upgraded for enabling the charging of high current batteries in the order of 100 AH to 250 AH.

An outboard transistor TIP36 is appropriately integrated across the IC 338 for facilitating the required high current charging.

The emitter resistor of TIP36 must be calculated appropriately otherwise the transistor might just blow off, do it by trial and error method, start with 1 ohm initially, then gradually go on reducing it until the required amount of current becomes achievable at the output.

#### hitman

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1. sir,what is the total estimate of the project?

1. Oh great, it's already there, I didn't remember that I already have one solar inverter article posted in this blog.

You can make this circuit, the total cost approximately would be around Rs5000/- , excluding the solar panel.

2. Sir, I am not able to understand the circuit diagram properly... Could you please elaborate it..?

3. Hi Naina,

The explanation will be huge and cannot be accommodated here, you will have to understand it yourself, I will guide you if required.

2. Hi,
I just want to know the use of the NAND gates and the MOSFET's.

1. N1 = wired as an oscillator,

N3, N4 = Wiredas biffer and for alternate pulses for the mosfets.

Mosfets are used for receiving alternate 50 HZ pulse from the respective gates N3, N4, and conduct alternately for powering the transformer and for producing the output ac.

3. thanks a lot for the prompt reply. I am making this for my final year diploma project in electronics and communication.

1. OK, good wishes to you.

4. Sir,
I would like to know if we increase or decrease the resistor values in the circuit, what will be the affect on the performance of the circuit? Also, kindly let me know the ideal rating for the battery used and the maximum load permissible.
Thanks.

1. Different resistors are there for different functions.

Battery and the transformer can be modified for getting a max 200 watts of power from this circuit.

5. Sir, what is connected between mosfets and transformer with a red +ve mark.
Thanks

6. Sir,
One more thing, connection from the battery's -ve terminal is going to unused nand gate.
How this circuit will work without connecting -ve terminal to somewhere else?

1. I have corrected the diagram, please check it now.

7. Thank you Sir

8. Sir,
Please give us 1000w solar inverter circuit.
Thanks.

Best Regards.

1. OK, I'll try to post one soon...

9. Thank you very much Sir.

10. Sir, I have some very useful circuits too.
But I don't know hot to post it on your blog.

Thanks.
Best Regards.

1. Hi Rashid,

You can send them to homemadecircuits@gmail.com I'll be most glad to publish them in my blog.

But kindly note that the diagrams should be your own creation or at least drawn by you.

Thanks and Regards

11. Sure Sir, I will mail you soon.

Best Regards.

Rashid R. Ansari

12. sir can we make solar panel without any transformer ?????

1. do you mean solar panel inverter without transformer???

13. sir is this really works?

1. The concept is correct according to me....so should work

14. sir , i also work on a project related to solar panel. i want to know cheap and perfect circuit of a 150 watt inverter , so guide me sir..

1. I'll try to find a simpler circuit, if i find one will surely contact you.

15. Where can i get the detailed working of this circuit? As in the function of individual components in converting dc to ac.

1. Here:

16. Thanks a lot sir. :D.

17. For generating 10 A. Each solar cell should have what specifications if using 72 cells.

1. If put in series all should be rated at 10A, if put in parallel then each may have 10/72 = 0.13 amps rating

18. I am making this project. Can you please tell me required components and the specifications of each component. We will not require large amount of power. I am going to buy the components tomorrow. So I want to make sure that there is no problem. A 12 v car battery is okay? Please help me

1. The circuit has not been practically tested, especially the inverter section. Though I believe this circuit should work, I cannot provide any guarantee regarding its working.

Kindly read the "disclaimer" at the top left of the page.

Regards.

19. I know that it's just in theory. But I just want to know what specification components you recommend.

1. All resistors are 1/4w, CFR, 5% except R3/R4 which are 3 watts rated wire wound type.
The 7812 caps may be non polar or electrolytic.
C1 is disc ceramic type,
The BC557 transistor is wrongly given, it should be BC547.

Rest of the materials are as given in the diagram....

20. can you give me the detailed design and the formulas used.also let me know about the reference books that will be useful to know more about the topic

1. There are not much calculations to be done, the formula for setting N1 may be understood from this article:

The formula for calculating R3/R4 has been already given in the article. You can get more info here:

21. From the negative end of the battery you have connected to the ammeter from that you have connected to the unused gate before that u gave one space is that jump or connection in between them.

1. Yes it's a jump, if you connect it, would create a big short circuit.

22. What would create a short circuit?

1. Please refer the above comment by Prince.

2. Hi Swagatam,

do you have any thing based on microcontroller

3. I'll try to update MC based circuits too in this blog soon....

23. Can you suggest a solar panel for my project. Need just enough power for few bulbs. Around 80 watts. Can you suggest a panel configuration? Which I can buy practically.

http://jiaxingyuantong.en.alibaba.com/product/295531864-209437812/80_Watt_Solar_Panel_12V_DC_RV_Battery_Charger.html

24. What ia the value of r3 and r4?

1. R3 = 0.7/I, where I = 1/10th of the battery AH

R4 =2R3

25. hi sir am a final year engineering student and i want a project on invertor and charging controler for a solar panel.

1. Hi Willie,

You can try the circuit discussed in the above article.

26. hi sir a final year engineering student and i want a project on invertor and charging controller for a solar panel.

27. Sir,
If a panel of about 50-80W is used. What changes in the values of the components will be required? I am making this project. But we are just going to use it to power few bulbs. Hence, the power requirement is not high. Please help me.
Thanks.

1. No changes will be required, just make sure the open circuit voltage of the panel does not exceed 30V.

28. we have already one inverter in home... if we buy solar panel and give connection to tat inverter means its enough or we need to buy new inverter???

29. No need of buying a new inverter, you can directly connect the following circuit to your existing inverter unit.

30. Can we make the solar panel inverter without transformer?

1. Yes we can make it, but it will work only during day time...

31. Can I know the rating of R3?

1. R3 = 0.6/Battery charging rate

32. Is it sufficient to use a 30V/8A solar panel for this circuit...?
If not, please mention the appropriate ratings of the battery?

1. Yes that will be more than sufficient, because the IC will pass not more than 5Amps to the battery.......the battery can be rated at 25AH

33. hello sir, i am doing a project based on solar inverter. if you dont mine, will you help me i need some clarification about this circuit if you are intrested plese send me some information about this to my mail id: karanpanday007@gmail.com

thankyou sir.

1. You can ask the questions here, I'll try to answer it.

34. How much battery for 1000w solar inverter?
How many hours backup time?

I need detailed circuit for solar inverter
my id : inventerkkd@yahoo.com

1. Battery will depend on how much load you want to drive from the inverter. THe battery AH should be at least 3 to 4 times the load current.

35. sir, i want a circuit diagram for connecting both solar current & normal home current to a inverter which is in my house

1. You may try this circuit:

36. Which battery can be used? I am making this for my project. Car battery is very expensive.

1. smaller battery will produce less power, bigger batteries will produce more power.

you may use a 12V 10 AH SMF battery.

37. sir, i am doing project on solar power inverter .inverter rating is 6 KVA where can i find circuit diagram for this inverter plz help me sir.

1. I tried to search online for a 6kva inverter circuit but couldn't find any....if I get one luckily will inform you.

38. sir can we connect solar pannel directly to inverter without battery banks? help me

1. In the above circuit?? yes it may be done.

39. sir for my final year project i need a inverter circuit which can directly convert solar pannel dc voltage into ac without using battery.please reply and help me.i can't get answer nowhere.help me plzz. my mail id: sankar.sankar25@gmail.com

1. You may use the above shown circuit, just remove the battery from its position and also the ammeter, diode switch etc.

2. sir for connecting pannel directly to 200watt inverter what is the wattage of solar pannel i need?

3. wattage can be anything, but voltage should not exceed 15V

40. can we use 100ah battery for this circuit? and what is the output wattage of this inverter?

1. 100 ah can be used for longer backups, the wattage will depend on the current ratings of the mosfets, transformer and the battery.

41. sir i want to use 100 watt 12volt solar pannel and 100ah battery with 200watts inverter output, is this possible in this circuit,if yes what are the modification i want to do in this circuit.reply please..

1. yes it's possible according to me, you will have to use a 12-0-12/20 amp transformer, 30amp mosfets for getting 200 watts.

42. is this circuit need charge controller?

1. over-charge controller might be required if you want it to be automatic.

43. sir the unused gate is not connected please give the corrected diagram url link..

1. the diagram is correct........"unused" refers to "not connected".

44. from where we can give +ve and ground to nand gate.

1. from the supply which would operate the inverter.

45. sir what is the use of ic7812.

1. the ic cannot tolerate more than 15v, the 7812 ic restricts the voltage to 12v and stops damage to the IC from high voltages.

46. sir to use change over relay in this circuit as you shown in one of your solar inverter. where should i connect relay in this circuit to change inverter circuit from solar pannel to battery in night time.

1. You will have to use a light sensor/relay driver as shown in this circuit:

47. sir i am building a solar panel. in panel each solar cell is 3.10 watt and total 36 cells(111.6watts) i think it produces nearly 32volts. is this circuit useful for my panel please help me

1. Yes the above circuit will work but the input voltage should never increase above 32V, that's the max tolerable threshold of the IC.

48. sir is this charge controller is maximum power point tracking type ,if no please give MPPT charge controller for 12 volt 10 amp solar pannel.

1. No the above design is a voltage/current controlled charger not MPPT.......MPPT require uprocessors, which is difficult to design and optimize

49. sir if my solar panel produces more than 40volts what changes i have to do in the circuit please help me

1. No, the above circuit cannot be modified for voltages above 32V.

You may try the following circuit instead:

50. Sir could you please tell me the Ic number for 30 amps mosfet.

1. irf540N will do.

51. sir,could you plz send the design of this circuit diagram...

1. If I get time I'll surely try to update the PCB layout here.

52. sir how to build a 1kw inverter

1. You can try this circuit:

53. sir plz give me clear circuit diagram of Solar Inverter Circuit.. i give my mail address (geevi003@gmail.com)

54. Cool baby, please click the diagram to enlarge it

55. what kind of converter used in this circuit sir?
buck,boost or buck boost

1. ordinary boost or step-up inverter

56. what is the operation of ic7812?

1. to provide safe voltage to IC4093

57. sir is this circuit give 220 volts ac output if it is OK then can we connect 200 ah battery please help me?

1. The inverter will give a 220V ac, and yes you can connect a 12V 200AH battery with it, but the solar panel/controller will not charge a 200 ah battery.

2. why sir? then how can i recharge the battery

3. The IC 338 can handle only upto 5amp which will allow charging of upto 50 ah batteries, not above that.

You will have to connect an overboard transistor for upgrading the current capacity of the circuit.

58. sir this charger can charge 100ah battery? if no what are the modification i have to do.

1. I have updated the article, please check it.

59. What is the number of the two 10 amp diodes used in the circuit?
Can i use MIC BR34 12 amp. It is a bridge rectifier.

1. Actually it should be 30 amps each.....use 3 in parallel for each diode.

60. Sir, do you have the layout for this circuit? I need it for my project. Please help.

1. I am sorry, layout will be difficult for me to provide....you will have to do it yourself.

61. hello
please can you explain the connections of the gates i dont understand them

1. The inputs of each gate are shorted together. Please refer 4093 datasheet to know about the gate pin out numbers.

62. your are genius. please add battery protection circuit ( over charging and low voltage cut off circuits)

1. Thanks, I'll try to do it soon...

63. sir how to connect a solar panel to general inverter.

1. You will have to incorporate a charger/controller circuit between the inverter and the panel, as shown in the above article.

64. sir can i connect 100watts solar pannel to drive load of 100 watts directly.
or what is the wattage of solar pannel i need to connect 100 watts load directly with 40ah battery charging.

1. Your question is not clear...what kind of load do you want to connect? Due you want to connect a battery as the load? Is there an inverter involved? please clarify.

65. sir i want to connect 100 watts load directly without battery. what is the wattage of solar pannel i need?

66. what is the purpose of switch s1?

1. during night when there's no solar power, S1 may be switched ON for connecting the battery with the inverter.

67. can we make solar panel by our own,,by the reference in youtube??

1. yes we can make it as per the guidelines.

68. sir i am building a solar panel it gives nearly 50volts dc out put please suggest me a good inverter circuit

1. what is the current output of the solar panel?

69. hi sir,what will be the cost of production?....
is it possible to make a model for mini project with low cost?.....

1. Hi Rakesh,

I am not sure about the cost....you will have to inquire with your local dealer.

The above circuit is itself quite mini.

70. sir will you help me to make a simple solar inverter for my mini project?
and also circuit diagram and required components,
plz sir...

1. you can try this circuit:

71. sir
can we use general inverter substitute of solar grid inverter for the solar panels if possible please help me

1. You mean using a general inverter as a grid tie inverter?

No that would be disastrous.

72. sir can you give substitute ic for LM338 and TIP36. these are not easily available

1. sorry, there's no substitute for them....

73. sir, i am bisically a 4th year student from EEE branch and opting for solar power invertor for the main project.
requirements: invertor design which can illuminate 2 tubelights and a fan for our own class room. Can u suggest the circuit for the above requirement.

1. You may try the above shown circuit, if the transformer and the battery are appropriately rated would provide you with the required power.

74. sir ,
i want 250VA ups circuit diagram..

1. I'll try to post it soon.

75. sir,i wank 1kw solar inverter circuit diagram with correct ratingsplz

1. make the above circuit first then upgrade it to 1kva.

76. Great job Sir. I need a programme to make my circuits like yours which seem neat!

Can you please tell me what is the programme that you are using? It gives nice diagrams!
Can it do simulations of the behavior of the components?

I am using Pspice at the moment which I don't find handy at all and it lacks a lot of components that I need to find and download through libraries.

1. Thanks!

I use corelDraw for drawing the schematics, the symbols are all drawn by me and stored in the "symbol manager library" so that I can use it whenever I need them while drawing the circuits.

77. sir,i want to do solar street light system for real time using from one street i want to connect paralley anothey 5 lights how much battery rating will be used,and i also want to do solar inverter for that how rating it should contain...

1. it will depend on the wattage of the connected lamps or the load.

2. pannel is 100w we r using.battery 24v

3. what is the wattage of the lamps??

4. 60W LED for one street light

5. for supporting the 5 posts you would require a battery that would keep 60 x 5 = 300 watts illuminated for 12 hours....a 200 ah battery would be required for it.

78. can i use this charge controller for charging 12 volt battery.

79. sir I am having an inverter circuit with 1.2kw ..some of them are saying there some mistakes in that circuit cau you help me where is the mistake....

80. Sir,
you are indeed a great brain.

Kindly help me out with the steps to designing an inverter rated 3kva.
I am also ready to work with u.
I will also want to know if there is any training available on designing electronics circuits.

1. Thanks!

81. sir the R1 value depend on charcing current then how can i connect load directly without batery. if i want to connect one ceiling fan as load with 100 watt pannel without battery then what is value of resistor.

1. That's a good question, if you are using the system directly without a battery then you may set R1 such that it allows only the amount of current which doesn't exceed your maximum load ratings.

example if your load is 100 watts, divide this with 12, 100/12 = 8.33Amps

Next, 0.6/8.33 = 0.072 ohms, this would be the value of R1.

82. sir if i want to connect 40 ah battery to this inverter, then that 40amps current will damage the IC or not. what can i do to protect oscillator IC.

1. there won't be any problem as long as the rated voltage is 12.

83. sir when i give 12volt for this inverter from regulated power supply i get 45 volt in the output of transformer. i cant troubleshoot. please tell what will the problem.

1. your power supply should be 10 amp rated.

84. sir you told that if transformer is 15 amps then the output can increased to 200 watts. (15amp*12 volt). then for 1kva inverter we need huge transformer???
then how power is increased for high power output.

1. for getting 1kva with 12v you will require a huge transformer....you need to increase the Volts to may be 60V for reducing the size....as volts increases current decreases and so does the size of the trafo....

85. sir, the open circuit output voltage i measured is 450volt(overvoltage). but when i connect frequency meter for testing i get voltage value as 210volts. why?

1. at which points did you check the voltages?? I didn't quite understand your question...

2. transformer secondary(hv side).

3. what is the input voltage?

by the way a frequency meter will show frequency, and not voltage...

86. how much power will this inverter consume.(self consumption)

1. about 20% of the output

87. is there any advantages in using this regulator circuit over one which we buy in shop.

1. yes, one big advantage: you can see the circuit here, understand the functioning, and optimize the results as per your specs and desires.

88. sir i use general purpose pcb to for soldering this circuit and i used single strand bread boarb wire for inter connections. when i connect this circuit to 12volt 40ah battery the wires get melted. what can i do??????

89. there may be a short circuit in you connections, check it properly, disconnect the inverter section, and connect only the charger section first to the battery.

90. what type of wire should i use for circuit connection too withstand high current(40AH). when i connect this circuit in 2 amps 12 volt supply the circuit is working but when connected to 4oAH supply wires get melted.

1. what load have you used with the inverter???

2. at 100 watts, your circuit will consume 100/12 = 8amps, so use wires which can withstand 10 amps of current, use industrial motor wire for the connections.

3. can i use this thick wires for interconnection of components(IC) in general purpose pcb.

4. which wires are burning?

replace only those wires.

91. sir i built a solar panel with 111.6 watt the panel is giving output of 20volts how can i charge the 150ah battery and how many hours will take to fully recharge the battery. please help me sir

1. you may utilize the last circuit LM338 stage for chaging the battery, it might take about 7 + 7 hours (two days) to get fully charged under full sunlight.

92. can i run a ceiling fan with this inverter using 20ah 12volt battery.

1. yes you can do it.

93. sir,
what was R3 resister range in the ckt? can you plz tell me?

1. It will depend on the battery AH rating...

94. sir, where to connect the load and see the output?

1. Across " Mains AC Output" points

95. sir in day time pannel is connected to battery and load. For battery it need 14.4volt for charging. for load(inverter) it need 12.6volt(as battery) so how to vary regulator voltage to supply the both.

1. That won't be possible, because the charger has only one control in the form of P1.... what kind of load have you connected??

You can probably add three 6A4 diodes in series with the positive for feeding the load, this would drop about 2V from 14.4V.

2. can i use 12volt zener diode in parallel to reduce 14.4 volt to 12 volt.

3. no that would be wrong...

96. sir 1)the regulator maintains the voltage when exceeds the fixed value but not maintain when reduced below fixed value why?
2)is there any way to maintain voltage at 14.4 when voltage varies from 10volt to 18volt.
3) what type of regulator is this boost or buck.

1. LM338 will provide a precise fixed voltage as per the setting of the pot with any input that's 1 volt higher than the set voltage, upto 30 volts max.

please refer LM338 datasheet to get all the info.

97. when i connect this inverter to 12volt 20ah battery the output voltage i get is 290volt. how can i get 220 volt.(transformer used is 12-0-12volt 10 amps)