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Automatic 40 Watt LED Solar Street Light

Today solar panels and PV cells have become very popular and in the near future we would possibly see everyone of us using it in some or the other way in our life. One important use of these devices has been in the field of street lighting.

The following article discusses one such interesting circuit which comprehensively explains the making of a 40 watt fully automatic solar street light system circuit (exclusively designed by me).

The circuit which has been discussed here has most of the standard specifications included with it, the following data explains it more elaborately:

LED Lamp Specifications


Voltage: 12 volts (12V/26AH Battery)

Current Consumption: 3.2 Amps @12 volts,

Power Consumption: 39 watts by 39nos of 1 watt LEDs

Light Intensity: Approximately around 2000 lm(lumens)

Charger/Controller Specification


Input: 32 volts from a solar panel specified with around 32 volts open circuit voltage, and short circuit current of 5 to 7 Amps.

Output: Max. 14.3 volts, current limited to 4.4 Amps

Battery Full - Cut OFF at 14.3 volts (set by P2).

Low Battery - Cut OFF at 11.04 volts (set by P1).

Battery charged at C/5 rate with float voltage restricted to 13.4 volts after “battery full cut OFF”.

Automatic Day/Night Switching with LDR Sensor (set by selecting R10 appropriately).

In this first part of the article we will study the solar charger/controller stage and the corresponding over/low voltage cut-off circuit, and also the automatic day/night cut-off section.





Automatic 40 Watt LED Solar Street Light Circuit Project - Part-1


Parts List


R1, R3,R4, R12 = 10k
R5 = 240 OHMS
P1,P2 =10K preset
P3 = 10k pot or preset
R10 = 470K,
R9= 2M2
R11 = 100K
R8=10 OHMS 2 WATT
T1----T4 = BC547
A1/A2 = 1/2 IC324
ALL ZENER DIODES = 4.7V, 1/2 WATT
D1---D3,D6 = 1N4007
D4,D5 = 6AMP DIODES
IC2 = IC555
IC1 = LM338
RELAYS = 12V,400 OHMS, SPDT
BATTERY = 12V, 26AH
SOLAR PANEL = 21V OPEN CIRCUIT, 7AMP @SHORT CIRCUIT.

Solar Charger/Controller, High/Low Battery Cut OFF and Ambient Light Detector Circuit Stages:


Referring to the 40 watt street light circuit diagram above, the panel voltage is regulated and stabilized to the required 14.4 volts by the IC LM 338.

P3 is used for setting the output voltage to exactly 14.3 volts or somewhere near to it.

R6 and R7 forms the current limiting components and must be calculated appropriately as discussed in this solar panel voltage regulator circuit.

The stabilized voltage is next applied to the voltage/charge control  and the associated stages.

Two opamps A1 and A2 are wired with converse configurations, meaning the output of A1 becomes high when a predetermined over voltage value is detected, while the output of A2 goes high on detection of a predetermined low voltage threshold.

The above high and low voltage thresholds are appropriately set by the preset P2 and P1 respectively.

Transistors T1 and T2 respond accordingly to the above outputs from the opamps and activates the respective relay for controlling the charge levels of the connected battery with respect to the given parameters.

The relay connected to T1 specifically controls the overcharge limit of the battery.

The relay connected to T3 is responsible for holding the voltage to the LED lamp stage. As long as the battery voltage is above the low voltage threshold and as long as no ambient light is present around the system, this relay keeps the lamp switched ON, the LED module is instantly switched OFF in case the stipulated conditions are not fulfilled.

Simulation and Working


IC1 along with the associated parts forms the light detector circuit, its output goes high in the presence of ambient light and vice versa.

Assume it's day time and a partially discharged battery at 11.8V is connected to the relevant points, also assume the high voltage cut off to be set at 14.4V. On power switch ON (either from the solar panel or an external DC source), the battery starts charging via the N/C contacts of the relay.

Since it's day, the output of IC1 is high, which switches ON T3. The relay connected to T3 holds the battery voltage and inhibits it from reaching the LED module and the lamp remains switched OFF.

Once the battery gets fully charged, A1's output goes high switching ON T1 and the associated relay.

This disconnects the battery from the charging voltage.

The above situation latches ON with the help of the feedback voltage from the N/O contacts of the above relay to the base of T1.

The latch persists until the low voltage condition is reached, when T2 switches ON, grounding T1's base biasing and reverting the top relay into the charging mode.

This concludes our battery high/Low controller and the light sensor stages of the proposed 40 watt automatic solar street light system circuit.

The following discussion explains the making procedure of the PWM controlled LED module circuit.

The circuit shown below represents the LED lamp module consisting of 39 nos. 1 watt/350 mA high bright power LEDs.The whole array is made by connecting 13 number of series connections in parallel, consisting of 3 LEDs in each series.

How it Works


The above arrangement of LEDs is pretty standard in its configuration and does not focus much importance.

The actual crucial part of this circuit is the IC 555 section, which is configured in its typical astable multivibrator mode.

In this mode the output pin#3 of the IC generates definite PWM wave-forms which can be adjusted by setting the duty cycle of the IC appropriately.

The duty cycle of this configuration is adjusted by setting P1 as per ones preference.

Since the setting of P1 also decides the illumination level of the LEDs, should be done carefully to produce the most optimal results from the LEDs. P1 also becomes the dimming control of the LED module.

The inclusion of the PWM design here plays the key role as it drastically reduces the power consumption of the connected LEDs.

If the LED module would be connected directly to the battery without the IC 555 stage, the LEDs would have consumed the full specified 36 watts.

With the PWM driver in operation, the LED module now consumes about 1/3rd power only, that is around 12 watts yet extracts the maximum specified illumination from the LEDs.

This happens because, due to the fed PWM pulses the transistor T1 remains ON only for 1/3rd of the normal time period, switching the LEDs for the same shorter length of time, however due to persistence of vision, we find the LEDs to be ON all the time.

The high frequency of the astable makes the illumination very stable and no vibration can be detected even while our vision is in motion.

This module is integrated with the previously discussed solar controller board.

The positive and the negative of the shown circuit needs to be simply connected to the relevant points over the solar controller board.

This concludes the whole explanation of the proposed 40 watt automatic solar LED street lamp circuit project.

If you have any questions, you may express them through your comments.

Circuit diagram for the street light LED PWM controller



Parts List


R1 = 100K
P1 = 100K pot
C1 = 680pF
C2 = 0.01uF
R2 = 4K7
T1 = TIP122
R3----R14 = 10 Ohms, 2watt
LEDs = 1 watt, 350 mA, cool white
IC1 = IC555

In the final prototype the LEDs were mounted on special aluminum based heatsink type PCB, it is strongly recommended, without which the LED life would deteriorate.

Prototype Images







Need Help? Please leave a comment, I'll get back soon with a reply!




Comments

  1. what is the rating of your solar panel? Battery rating will need to be calculated according to it.

    ReplyDelete
  2. i want to make a automatic solar charge controller for 12V 60ah lead acid battery having 60W load to operate. and i'm having panel of 150w. please suggest me circuit my email sunsolarpower2@gmail.com

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  3. You can use the circuit shown in the above article, just remove the IC555 (green IC) from the design, and use the rest of the circuit for your application.

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  4. Thank you so much sir, I'll try and get back to you, Thank you

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  5. sir R6,R7 VALUE confused calculation please 60ah battery

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  6. R7 = 0.6/6 = 0.1 ohms

    don't use R6, replace it with a wire link.

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  7. Thank you so much sir, I'll try and get back to you Thank you and Good Night

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  8. Thanks can we use lm 350 since its current rating is 3A

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  9. hi, i have a few questons.

    1. how many hours will the battery take to discharge completely if 40 LED's are used as in your circuit.
    2.Is R10 min LDR circuit a preset or fixed. if fixed can a preset be used and of what value???
    3. where are full/low battery and ambient light indicators are connected in schematic???

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  10. With a 26ah good condition battery it will take around 10 hours to discharge.

    R10 can be replaced with a 1M fixed resistor.

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  11. I'll update the circuit soon with the LED indicators.

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  12. Sir how to adjust p1 and p2 values nd my battery is of 18ah so what will b value of R7

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  13. apply 14V to the circuit adjust p1 such that the top relay just activates.

    Now reduce voltage to 11V and adjust P2 such that the above relay just deactivates.

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  14. i used lm 350 bt the output is low
    hw to adjust the output in the voltage regulator

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  15. sir, i am siva the circuit connection complet.
    555 ic section not work, led o/p relay not work what my mistake

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  16. sir, this circuit connection couplet, 555 ic section not work, battery low full position confuse led o/p relay not work help me

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  17. sir circuit connection complet, 555ic section not work, p1 p2 alinment confused, led relay not work, help me

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  18. sir circuit connection couplet, 555ic section not work , p1 p2 aliment confused , led relay not work help me what my mistake

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  19. can you bring the circuit to me, i'll show you what faults you have made....

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  20. use 1M for R10 and then focus some light on the LDR, check the the output LED response.

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  21. sir, 13.98v battery full, 11.04 low which is the pin aliment, 1m r10 focus light LDR 4.89v come change the relay. ldr set the PCB and near led so light distrupe?

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  22. adjust P3 to get 11v across D5 cathode and ground. then adjust P2 to activate the upper relay.

    then adjust P3 to increase voltage to 14V, then adjust P1 to deactivate the upper relay and activate the lower relay.

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  23. can lm396 be used in place of lm338. it supply 10 ampere

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  24. lm338 is not available in my area. any 15v 5a supply will be fine i guess in place of lm338

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  25. ic 324 have 4 comparator in one ic can single ic be used???

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  26. you forgot to mention value of C1 capacitor

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  27. lm 338 was not available so i used lm7815 with transistor d1047 (connecting input of 7815 to collector, output to base)for current more than just 1 A(output from 7815). is this arrangement ok???
    secondly how much max current can bc547 can pass??? can i use d1047 in place of bc547 if bc547 cannot supply current upto 2.5 A? if yes then what other changes do i need to make.

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  28. yes only a single is required here.

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  29. where do you want to use BC547?

    BC547 can handle only upto 100mA

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  30. Hello Tanmoy,

    You can use the above circuit for your application with the following modifications:

    Remove the IC2 section entirely and connect the D6 anode with D5 cathode.

    That's all is required rest all will be as is, the circuit will start functioning as per your specifications.

    ReplyDelete
  31. I want to use this circuit as a college project but i need to finish it and put it in a reasonable cover and hence its a street light i was wondering if it will be possible to put the battery somewhere in the head of the street light

    Also is it possible to get a small solar panel that will give me the required 14.4V i need to charge the battery

    Thank you

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  32. The battery can be installed anywhere around the light box, but should be appropriately enclosed and protected from water and direct sunlight.

    The desired soar panel can be easily procured from your nearby electronic market.

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  33. Thank you, will get in touch as i progress along

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  34. my ratings are 12v 5 watts solar pannel and battery is 12v 1.3 ah will this circuit can be made with this ratings? if not suggest me the appropriate ratings for low power (5-10 watts)

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  35. the above circuit can be used with the specified components

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  36. hi.
    there is some problem with this circuit. when i set A1 it works normally when i move voltage level up and down from P3. but when i adjust A2 for low cuttoff then although A1 changes its output indicated by empty and full led but relay doesnot deactivates. it seems as it creats some latching with relay of A2. again when i adjust A2 preset to zero value the A1 relay works properly. any suggestions???

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  37. Hi, the above design is absolutely correct, there could be some problem with your assembly or parts.

    Or the slight delay may be happening due to the zener diodes in series with the transistor bases, which is not a big issue.

    For exact confirmation you can replace these zeners with LEDs, and remove the existing LEDs across the opamp outputs.

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  38. can you plz explain how to make these connections on bread board?? we are making this our project so plz help us to give connections, plz reply to shivaprasad8199@gmail.com

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  39. you can refer to any online "breadboard tutorial" site, there are plenty of them.

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  40. can u tell the pcb connection for this
    ples share the link

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  41. We are using a 10 watt solar panel, 12volt battery, what are the resistor values, of r2, r6,r7.... We should use.., plz reply us fast,

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  42. I am using a 12volt, 10 watt solar panel, and a battery of 12 v nd led light of 12v, what are the values of resistors of r2,r6,r7, nd what should be the output of battery,...plz rply fast i need to attach only these 3 on pcb, ty

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  43. provide battery ah??
    where's r2, r6?

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  44. Its ok there is no r2&r6, what should be r7 fr above prescribed values

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  45. R7 will depend on battery AH

    divide battery AH by 10, and place the result in the following formula:

    R7 = 0.6 divided by the above result

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  46. hi swagatam
    can i use this circuit for home light systems. there is some questions:
    1: There is no R6 & R2 right?
    2: As led 12v bulb light used as gives low light as length of wire increase what should we do for loss of power?
    3: What is max watt of panel & Ah of battery is used?

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  47. Hi Ashok,

    1.R6/R2 have been removed so it's not there in the present diagram.

    2.You can connect the Ac/DC adapter or the battery very close to the LED circuit and install them as one module over the desired location, this will solve the issue.

    3.It's not limited to any value, only the voltage of the two must not exceed above 24V.

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  48. thanks for reply.
    As you stated 2 comment what i do for all light grid in home in all room.
    and my first question can i use above circuit for home light system as charger & power supply.

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  49. yes it can be used, please provide all the details regarding your requirement? I'll try to figure out the procedures.

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  50. Ok i want use 1 watt LED that is in your next artilcle in three room. in which distance is 1st 12feet 2nd 20feet 3rd 30ft from Battery & charger point.
    1: so my question is there is loss due to distance?
    2: What is consumption of power take by LED light of 39 no of LED
    3:I want to use 20 watt*2 panel & 7 AH 2 batteri is it ok?

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  51. the distance will not cause much of a problem, since copper wire resistance will be hardly in milliohms for the mentioned distances.

    39 LEDs will consume 39 watts if each LED is 1 watt rated.

    7AH will last only for 4 to 5 hours if 20 watt is used with it.

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  52. Hi sir
    There is LM 338 ic1 not available in local area any equal part please help me?

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  53. can we use LM 317/LM350?
    please give me specification of LM338

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  54. LM350 can be used, but will require a larger heatsink than LM338.

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  55. Can we use computer UPS with 12v/ 45AH battery as a INVERTER for home use?
    I have one UPS with inbuilt 7 AH battery i want to use above circuit to charge 45 AH battery and UPS as inverter. Can we do it?

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  56. another question is what type and size of cables are used from solar panel & charge controller to load is used?

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  57. UPS can be used as an inverter also.
    the above circuit can be used for charging a 45AH battery.

    45AH will produce 5 times more backup than 7AH

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  58. I assemble the circuit i observe following:
    1: voltage at solar input 18.9 volt
    2: voltage at D5 is 13.02 volt
    3: Voltage at battery connection 13.02 volt
    is this ok? how to chk LED point? Actually i print the pcb at a time & assemble & chhk the circuit

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  59. I assemble he circuit but i chk voltage at battery connector & D5 voltage is 14.4volt as in put from solar is 20.8 volt i adjust but thr is no changes in voltage. How to make cut off by adjusting P1 & P2 that means from which point 14.2 volt & 11.01 volt has to put?

    please help me....

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  60. it will depend on the current specs of the system.

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  61. voltage should be 14.3V after D5 without any battery connected, this must be adjusted with the help of P3.

    the LEDs will respond when P1 and P2 are set at their respective cut-of thresholds

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  62. don't connect the battery while setting up, I mentioned this in the previous comment also.

    initially use a 15 or 24V AC/DC adapter for supplying to the circuit, don't use solar panel

    without any battery adjust P3 to get 14.4V at the cathode of D5.

    Now adjust P2 so that the upper relay just activates, if it's already activated, adjust P2 to deactivate it and again adjust the same to activate it and seal P2.

    Now adjust P3 to reduce the voltage at D5 to 11.1V, and adjust P1 so that the upper relay just deactivates again, seal P1

    confirm the above actions by adjusting p3 back to 14.3V and 11.1V two three times.

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  63. Hi sir for long time i replied, actually i did not have variable voltage supply, now i assembled for the above circuit use. As you stated in above comment steps are as follow,
    1: disconnect battery supply at solar point 21-22volt dc using supply.
    2: adjust P3 to get 14.3 volt at battery point.( i do at this point)
    after that i rotate both preset but nothing happen with relay.
    3: adjust P3 to get 11.13 volt rotate P1 & P2 but nothing happen

    please guide me...

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  64. It means you might have done something wrong with the connections.
    Anyway,
    Initially keep the collector of T2 disconnected from the base of T1.
    Now adjust P2 to activate the relay at 14.4V.
    Reconnect T2 collector to T2 base and apply 11V.
    Now adjust P1 to switch OFF the relay.

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  65. sir actually i m confused can u explain my question answer. without battery connect, When i apply 21 volt supply at solar panel point, at battery point voltage is 14.3 v by adjusting P3 ok. Next at this point adjust P2 for battery full cut out without disturbing setup. next again without disturbing setup adjust P3 to 11.3 v output of battery point now adjust p1 for low cutout.
    is this battery point open right that is no connect battery just open those point. so without load at battery point how we can adjust low & full cutout?

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  66. yes it should be without any battery connected, the variable inputs simulate the battery threshold levels and is used for setting the relevant presets.

    ReplyDelete
  67. Hi,
    I want assembled prototype of this street light, how can i get it from you.
    my email: jeke117@gmail.com
    Thank you

    ReplyDelete
  68. Hi, I am sorry, presently I do not have it in stock, so won't be able to provide it to you at the moment.

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  69. Hi I need solar LED streetlight circuit with dusk to dawn operation using microcontroller. Can u provide?

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  70. hi, presently I do not have this design, I'll try to find and let you know.

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  71. Please let me know if you find it as am interested as well, with heat sink or cooling system

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  72. Heat sink only. When can I expect this? if u have pls. contact to my mail ljayarajuatgmaildotcom

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  73. you will need an aluminum base PCB for this circuit

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  74. Ya I will take aluminium PCB to place LEDs as required. Pls. provide charge controller and LED driver with dusk to dawn operation that should be common PCB for many LED loads with little bit modifications. The LEDs I will connect in series mode only.
    Thank u very much...

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  75. please do it exactly as given in the above article, for more LEDs you can add more number series connection to the existing LED configuration, as given in the next article.

    For a current control feature you can add the following circuit in between the battery and the LED module:

    https://homemade-circuits.com/2013/06/universal-high-watt-led-current-limiter.html

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  76. Thank u very much for ur response Mr.Swagatam. I need solar street light circuit which is operated on DC - 12V. I need Charge controller circuit having the facility to charge the battery, dusk to dawn operation and dimming operation and LED drivers on same circuit / PCB, using any PIC microcontroller. Pls. provide.Thank u

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  77. Pls. provide the circuit if u have 12A, 5A, SMPS circuits for which LED lights are operated on AC supply i.e. 230V. Thank u

    ReplyDelete
  78. Thank you! presently I do not have this design, I'll look for it and let you know as soon as I find one.

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  79. for a 12V5amp smps driver you can try this one:

    https://homemade-circuits.com/2014/03/12v-5-amp-transformerless-battery.html

    ReplyDelete
  80. hello sir, instead of 40W LED module, what can i use in my minor project. I want simple or cheap device in this place or which can i use as street light.

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  81. hello Mahesh, please mention the exact specifications of your requirement.

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  82. Hello Sir, the coil configuration of third relay(at extreme right side of the circuit diagram which is connected to LED lamp module) is no shown in the diagram.

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  83. Dipto, you can ignore this relay stage, it's not relevant to the twin battery charger design that you are presently building

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  84. Hello Sir,

    I need only LDR modul with IC555 for switching on/off with night or day. How to design circuit?

    Thank you

    BR

    ReplyDelete
  85. Hello fasat,

    you can try the last circuit shown in this article:

    https://homemade-circuits.com/2012/01/how-to-make-light-activated-day-night.html

    ReplyDelete
  86. sir i have 12v 75ah battery
    i want to charge through solar panel please give me the circuit
    and
    automatic night sensor with 4pin pl lamp 11w

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  87. Satish, you can try the last circuit from this article:

    https://homemade-circuits.com/2012/05/make-this-voltage-stabilizer-circuit.html

    just replace the input with your solar panel voltage

    for the light sensor you can try the last circuit from this article:

    https://homemade-circuits.com/2012/01/how-to-make-light-activated-day-night.html

    ReplyDelete
  88. Hello, i would like to build this circuit but was wondering if you have a stripboard layout for it because it will be easier to construct and instead of me spending time making one i thought to ask you..please help it will be really appreciated

    Thank You

    ReplyDelete
  89. It would be difficult for me due to time pressure and many pending assignments, I'll try though if I happen to get some free time...

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  90. Okay thank you for the good intention, i will give you some time and get back to you in 1 month i hope you can help me

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  91. sir please send how to connect relay 2 nc,no and common pins

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  92. sampath, it's clearly shown in the diagram, only N/C and the pole are used the N/O is unused for RL2...the coil is connected across the positive and the T3 collector

    ReplyDelete
  93. Sir what component should i replace for 18W,24W solar Steet light

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  94. you don't have to change anything in the circuit design, just reduce the number of LEDs in the LED panel proportionately

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  95. Sir what is R9 value is it 22M and R7

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  96. R9 = 2.2Meg



    R7 = (0.6 x 10) / Battery AH rating

    ReplyDelete
  97. What is the pin number of A1/A2 from which pin P1 and p2 and zener is connected that is +ve and -ve pin number

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  98. (+) is pin#3, and (-) is pin#2

    ReplyDelete
  99. Sir

    May i know basic design calculation of solar system.
    I am new for this design
    Please help me

    ReplyDelete
  100. sir i wanna make project same as this in small scale plz help me . I wanna glow a LED with solar power. I have also sold 3v solar panel but my circuit is not completed due to non availability of components (0.47mH 4R9 and 10R)

    ReplyDelete
  101. I can ask your specific questions, I'll try to solve them...

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  102. hello sir, what are the modifications to be done for an LED module output power of 15 watts. Thanks

    ReplyDelete
  103. you can use the same set up, no changes would be required

    ReplyDelete
  104. Dear sir, can you please mention the specs for capacitor C1, Resistor R7, LDR and power wattage for the solar panel. Also min and max LED output power that this circuit can support. Thanks

    ReplyDelete
  105. Dear sir, can you please provide more details on the LED lamp module. Orientation of the LEDs in that module. Are they connected in parallel or in series to each other. Also, what is the value of the current limiting resistors for each LED. Thanks

    ReplyDelete
  106. Dear Gopal, C1 can be any small value capacitor between 1uF/25V and 10uF/25V

    Max LED power for a 26AH battery can be 40 watts for 6 hour continuous backup

    ReplyDelete
  107. The details can be found in the following article:

    https://homemade-circuits.com/2012/10/automatic-40-watt-led-solar-street_2.html

    just make sure that the LEDs are separated by a distance of 1 inch and mounted on a aluminum based PCB with additional heatsink attached to the back side of the PCB.

    ReplyDelete
  108. I want to make Automatic 80 Watt LED Solar Street Light Circuit Project so can u plz tell me how many volts & amperes of solar panel is required...??? Should I double it compared to 40 watt...???? Please reply as soon as possible.... Please

    ReplyDelete
  109. Dear Mr. Majumdar. I am interested in 15-34 watt LED street light project without battery at Haridwar, Uttrakhand
    Would like to be dealer for same.
    Also is there any solution for automatic invertor battery charger when the light goes off.
    Also it is seen that qhen the light is on the use of battery is nil. Can there be a design which when invertor battery is full it should cut mains and go on battery backup upto letus say 50% or it can be adjustable as per requirement. This way use of battery will be at maximum and electricity bill be reduced. Kindly reply if u feel it a good idea.

    ReplyDelete
  110. you will require a 18-20V/5amp (minimum) solar panel, and a 12V 60AH (minimum) battery

    ReplyDelete
  111. Hi sir, I spoke to you before about the strip board layout if you could help me with a strip board layout of this circuit i hope you remember and I would like to follow up to see if you have had a chance to make one for me. Thanks

    ReplyDelete
  112. Dear Nauty,

    I already have the required battery charger design in my website, you can easily find the required from the "categories" list however the idea of having 50% supply from the battery during the mains presence will not do any good....because while the battery is supplying current to the load it is simultaneously acquiring it from the mains...so that would not help in saving mains power in any manner.

    ReplyDelete
  113. Hi ous, due to a very busy schedule it looks difficult to me at the moment, however if your requirement is for the LED pcb layout, then probably you could find an example design here:

    https://homemade-circuits.com/2012/11/making-40-watt-led-emergency-tubelight.html

    ReplyDelete
  114. thank you so much sir for replying....
    ?☺☺☺

    ReplyDelete
  115. Hello sir, I wanted to know if there is any modification required in the circuit if I make 80 watt automatic led Street Light.
    what is the value of R2,R6, & R7. what specification of LDR is used here.... I'll be waiting for your reply.....

    ReplyDelete
  116. Hello sir,
    I have one problem in my street light
    Panel 75w,20V
    Battery 75Ah , 12v

    O/p of controller to charge battery is 2.3volts
    O/p of panel is 20v
    Lamp is 15w 12v led

    Sometime operate and sometime don't opetate

    What can be reason

    ReplyDelete
  117. Can i charge 12v lead acid battery by directly connecting to 20v solar panel without charge controller for two days

    ReplyDelete
  118. Hello Preeti,

    if the battery is 12V then there would be no modifications required except R7, which will need to be calculated by the formula

    R = 0.7 x 10/battery AH

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  119. Hello Umesh, it would be difficult to understand the fault without a practical check up, but it appears that the unit is malfunctioning...

    yes you can connect the specified panel with the specified battery directly for the time being...it will still charge the battery, although not quickly.

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  120. Battery value is 12 V 26amps. R7 value is 2.6 Ohms. Its correct or not

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  121. battery is correct, R7 = 0.6 x 10/26 ohms

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  122. Are the zener diodes connected in series with the op amps?

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  123. yes in series with the output pin

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  124. can i know why is IC2 and componenets with it are used. Is it necessary to have that part or can be just omitted.
    thank you

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  125. it's for enabling an automatic switching ON of the LEDs in the evening and switching it OFF when day breaks.

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  126. Hello sir,
    I want to make this project but with some modification.. I want solar panel to follow the direction of sun.. something like solar tracker... so can you please help me with the circuit diagram.... I would wait for your reply....

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  127. Hello Preeti,

    A solar tracker is a precision mechanical device and would require a mechanical engineers guidance to construct it...one example cocept is shown here:


    https://homemade-circuits.com/2011/12/how-to-build-dual-solar-tracker-system.html

    ReplyDelete
  128. mthssolarguy@gmail.comJuly 12, 2016 at 7:56 PM

    Can you tell the wattage of the components in your design?
    What is a good source to order parts?

    mthssolarguy@gmail.com

    ReplyDelete
  129. all components are 1/4 watt except R8.

    All reputed online stores are good, you can google "buy online electronic parts" for the list of main vendors.

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  130. The IC is used simply as a comparator here, only the pin#2 opamp is utilized while the pin#7 opamp is kept unused....pin#5 connection with pin#7 helps to provide some degree hysteresis to the triggering.

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  131. Sir i have 74 watt solar panel, and 75AH battery. How to design a solar charge controller with LDR sensor and INDICATION LED of charging, discharging and low battery..

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  132. BR, you can try the following concept

    https://homemade-circuits.com/2017/01/universal-battery-charger-circuit.html

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  133. hello, actually it is 3.5 amps for the whole 40 watt LED module, and not 1.2 amp, I have corrected the article now.

    current through each LED will be around 300mA, volts = 3.3V
    panel should be much higher than 40watt, around 50 watts

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  134. actually I don't remember how a much lumens a 36 LED would produce, however with around 320mA per LeD would enable maximum specified lumens from it

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  135. hello Sir,
    I am facing a hard time drawing the circuit using Proteus, it is not working accordingly as i simulate, i am finding it hard to trace the error that i am doing, Your circuit design is correct i am at fault, to which email may i sent it for your assistance.

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  136. sorry Matty, I cannot diagnose a simulators results, if you are trying it practically then I may try to guide you through the steps.

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  137. Good day Sir,

    Will using a 40W solar panel be alright with a 12V/38 Ah battery?

    ReplyDelete
  138. Matty, a 38AH will require a 5 amp current for at least 7 to 8 hours, for charging to some optimal level, so make sure your panel is able to generate 5 amps for 7 hours

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  139. GOOD DAY SIR,
    What is the function of z3 and d1, and why was resistor R12 placed between the transistor and diodes. I understand the voltage regulator circuit but having a challenge to understand the configuration of over voltage and under-voltage charging of the battery.

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  140. Good day Vivian, the zener is to block leakage voltage from the IC output. the series diode is placed to block the other external voltages from entering the IC output, which are meant for the transistor base.

    R12 is the base resistor for T2, a transistor cannot work without a base resistor.

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  141. to understand over voltage and under voltage functioning, you will have learn how the opamp works like a comparator....simply put, when the non-inverting (+) pin of an opamp is at higher potential than its inverting (-) pin, then its output goes high (equal to supply level) in the opposite case the output shows a zero voltage.

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  142. Good day Sir,

    Thank you.

    ReplyDelete
  143. Hi, am Daniel from Kenya I purchasing a solar panel (mono)300w only to get disappointed. On a Sunny day the solar voltage goes upto around 36v open circuit and when connected to a battery, the voltage drops to that of the battery i.e if the battery has 11v it remains the same .please I need your advice,its rated open circuit voltage is 22.2V

    ReplyDelete
  144. Hi Dan, connecting a 36V panel directly with a 12V battery is simply bad, and inefficient, you are destroying the efficiency of the panel and also putting the batt into risk.

    The best method to correct this to use a buck converter circuit which will enable you to get the most from your panel and also ensure max battery charging efficiency.

    you can use this link:

    https://homemade-circuits.com/5v-pwm-solar-battery-charger-circuit/

    a easier but crude method is to use an LM338 circuit as shown below:

    https://homemade-circuits.com/how-to-build-solar-panel-voltage/

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  145. What are the changes to be made in the circuit for a 12W LED solar street light system having dusk to dawn operation Sir? Please help me.

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  146. No changes will be required in the circuit, you just have to reduce the number of LED chains accordingly to achieve the required specs

    ReplyDelete

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