The following article discusses the construction of an interesting 40 watt automatic LED street light circuit, that will automatically switch ON at night, and switch OFF during day time (designed by me). During day time the in-built battery is charged through a solar panel, once charged the same battery is used to power the LED lamp at night for illuminating the streets.
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 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.
The above design can be much simplified by eliminating the IC 555 stage and by connecting the day time relay cut OFF transistor directly with the solar panel positive, as shown below:
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:
CAUTION: A charge controller is a must for any street light system. You may find other designs on the internet without this feature, simply ignore them. Those can be dangerous for the battery!
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.
Circuit Operation
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.
UPDATE: The above theory of seeing high illumination with lower consumption due to persistence of vision is incorrect. So sadly this PWM controller only works as a brightness controller and nothing more!
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
Simplest Street Light Circuit
If you are newcomer and looking for a simple automatic street light system, then perhaps the following design will fulfill your need.
This simplest automatic street light circuit can be assembled quickly by newbie and installed for achieving the intended results.
Built around a light activated concept, the circuit can be used for automatically switching ON and switching OFF a roadway lamp or group of lamps in response to the varying ambient light levels.
The electrical unit once built can be used for switching OFF a lamp when dawn breaks and switching it ON when dusk sets in.
How it Works
The circuit can be used as an automatic day night operated light controller system or a simple light activated switch. Let’s try to understand the functioning of this useful circuit and how it is so simple to construct:
Referring to the circuit diagram we can see a very simple configuration consisting of just a couple transistors and a relay, which forms the basic control part of the circuit.
Of course we cannot forget about the LDR which is the prime sensing component of the circuit. The transistors are basically arranged such that they both complement each other oppositely, meaning when the left hand side transistor conducts, the right hand side transistor switches OFF and vice versa.
The left hand side transistor T1 is rigged as a voltage comparator using a resistive network. The resistor at the upper arm is the LDR and the lower arm resistor is the preset which is used to set the threshold values or levels. T2 is arranged as an inverter, and inverts the response received from T1.
How the LDR Works
Initially, assuming the light level is less, the LDR sustains a high resistance level across it, which does not allow enough current to reach the base of the transistor T1.
This allows the potential level at the collector to saturate T2 and consequently the relay remains activated in this condition.
When the light level increases and becomes sufficiently large on the LDR, its resistance level falls, this allows more current to pass through it which eventually reaches the base of T1.
How the Transistor Responds to LDR
The transistor T1 conducts, pulling its collector potential to ground. This inhibits the conduction of the transistor T2, switching OFF its collector load relay and the connected lamp.
Power Supply Details
The power supply is a standard transformer, bridge, capacitor network, which supplies a clean DC to the circuit for executing the proposed actions.
The whole circuit can be built over a small piece of vero board and the entire assembly along with the power supply may be housed inside a sturdy little plastic box.
How the LDR is Positioned
The LDR must be placed outside the box, meaning its sensing surface should be exposed toward the ambient area from where the light level is required to be sensed.
Care should be taken that the light from the lamps does not in any way reach the LDR, which may result in false switching and oscillations.
Parts List
- R1, R2, R3 = 2K2,
- VR1 = 10K preset,
- C1 = 100uF/25V,
- C2 = 10uF/25V,
- D1 ---- D6 = 1N4007
- T1, T2 = BC547,
- Relay = 12 volt, 400 Ohm, SPDT,
- LDR = any type with 10K to 47K resistance at ambient light.
- Transformer = 0-12V, 200mA
PCB Design
Using opamp IC 741
The above explained automatic darkness activated street lamp circuit can be also made using an opamp, as shown below:
Working Description
Here the IC 741 is designed as a comparator, wherein its non-inverting pin#3 is connected to a 10k preset or pot for creating a triggering reference at this pinout.
Pin#2 which is the inverting input of the IC is configured with a potential divider network made by a light dependent resistor or LDR and a 100K resistor.
The 10K preset is initially adjusted such that when the ambient light on the LDR reaches to the desired darkness threshold, the pin#6 goes high. This is done with some skill and patience by moving the preset slowly until pin#6 just goes high, which is identified by the switching ON of the connected relay and the illumination of the red LED.
This must be done by creating an artificial darkness threshold light level on the LDR inside a closed room and by using dim light for the purpose.
Once the preset is set, it may be sealed with some epoxy glue so that the adjustment remains fixed and unchanged.
After this the circuit may be enclosed inside a suitable box with a 12V adapter for powering the circuit, and the relay contacts wired with the desired road lamp.
Care must be taken to ensure that the lamp illumination never reaches the LDR, otherwise it may lead a continuous oscillations or flickering of the lamp as soon as it is triggered at twilight.
what is the rating of your solar panel? Battery rating will need to be calculated according to it.
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
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.
Thank you so much sir, I'll try and get back to you, Thank you
sir R6,R7 VALUE confused calculation please 60ah battery
R7 = 0.6/6 = 0.1 ohms
don't use R6, replace it with a wire link.
Thank you so much sir, I'll try and get back to you Thank you and Good Night
1 watt/350mA/3.3V
Any substitute for lm 338
sorry no identical substitute.
Thanks can we use lm 350 since its current rating is 3A
yes, will do.
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???
With a 26ah good condition battery it will take around 10 hours to discharge.
R10 can be replaced with a 1M fixed resistor.
I'll update the circuit soon with the LED indicators.
Sir how to adjust p1 and p2 values nd my battery is of 18ah so what will b value of R7
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.
i used lm 350 bt the output is low
hw to adjust the output in the voltage regulator
make P3 = 10k
sir, this circuit connection couplet, 555 ic section not work, battery low full position confuse led o/p relay not work help me
sir, i am siva the circuit connection complet.
555 ic section not work, led o/p relay not work what my mistake
sir circuit connection complet, 555ic section not work, p1 p2 alinment confused, led relay not work, help me
can you bring the circuit to me, i'll show you what faults you have made….
sir circuit connection couplet, 555ic section not work , p1 p2 aliment confused , led relay not work help me what my mistake
sir LDR equal resistor value?
use 1M for R10 and then focus some light on the LDR, check the the output LED response.
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?
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.
can lm396 be used in place of lm338. it supply 10 ampere
lm338 is not available in my area. any 15v 5a supply will be fine i guess in place of lm338
ic 324 have 4 comparator in one ic can single ic be used???
you forgot to mention value of C1 capacitor
yes LM196 or 396 will be fine.
a single 324 IC is used here.
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.
where do you want to use BC547?
BC547 can handle only upto 100mA
yes only a single is required here.
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.
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
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.
Thank you, will get in touch as i progress along
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)
the above circuit can be used with the specified components
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???
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.
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
you can refer to any online "breadboard tutorial" site, there are plenty of them.
can u tell the pcb connection for this
ples share the link
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,
provide battery ah??
where's r2, r6?
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
Its ok there is no r2&r6, what should be r7 fr above prescribed values
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
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?
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.
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.
yes it can be used, please provide all the details regarding your requirement? I'll try to figure out the procedures.
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?
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.
Hi sir
There is LM 338 ic1 not available in local area any equal part please help me?
can we use LM 317/LM350?
please give me specification of LM338
LM350 can be used, but will require a larger heatsink than LM338.
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?
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
another question is what type and size of cables are used from solar panel & charge controller to load is used?
it will depend on the current specs of the system.
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
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
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….
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.
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…
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.
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?
yes it should be without any battery connected, the variable inputs simulate the battery threshold levels and is used for setting the relevant presets.
Hi,
I want assembled prototype of this street light, how can i get it from you.
my email: jeke117@gmail.com
Thank you
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.
Hi I need solar LED streetlight circuit with dusk to dawn operation using microcontroller. Can u provide?
hi, presently I do not have this design, I'll try to find and let you know.
Please let me know if you find it as am interested as well, with heat sink or cooling system
Heat sink only. When can I expect this? if u have pls. contact to my mail ljayarajuatgmaildotcom
you will need an aluminum base PCB for this circuit
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…
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://www.homemade-circuits.com/2013/06/universal-high-watt-led-current-limiter.html
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
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
Thank you! presently I do not have this design, I'll look for it and let you know as soon as I find one.
for a 12V5amp smps driver you can try this one:
https://www.homemade-circuits.com/2014/03/12v-5-amp-transformerless-battery.html
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.
hello Mahesh, please mention the exact specifications of your requirement.
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.
Dipto, you can ignore this relay stage, it's not relevant to the twin battery charger design that you are presently building
Hello Sir,
I need only LDR modul with IC555 for switching on/off with night or day. How to design circuit?
Thank you
BR
Hello fasat,
you can try the last circuit shown in this article:
https://www.homemade-circuits.com/2012/01/how-to-make-light-activated-day-night.html
Thank you Swagatam.
BR
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
Satish, you can try the last circuit from this article:
https://www.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://www.homemade-circuits.com/2012/01/how-to-make-light-activated-day-night.html
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
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…
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
sir please send how to connect relay 2 nc,no and common pins
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
Sir what component should i replace for 18W,24W solar Steet light
you don't have to change anything in the circuit design, just reduce the number of LEDs in the LED panel proportionately
Thanku Sir
Sir what is R9 value is it 22M and R7
R9 = 2.2Meg
R7 = (0.6 x 10) / Battery AH rating
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
(+) is pin#3, and (-) is pin#2
Battery value is 12 V 26amps. R7 value is 2.6 Ohms. Its correct or not
battery is correct, R7 = 0.6 x 10/26 ohms
Sir what is the value of C1
C1 can be a 10uF/25V cap
Sir
May i know basic design calculation of solar system.
I am new for this design
Please help me
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)
I can ask your specific questions, I'll try to solve them…
hello sir, what are the modifications to be done for an LED module output power of 15 watts. Thanks
you can use the same set up, no changes would be required
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
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
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
The details can be found in the following article:
https://www.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.
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
you will require a 18-20V/5amp (minimum) solar panel, and a 12V 60AH (minimum) battery
thank you so much sir for replying….
?☺☺☺
you are most welcome Preeti!
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…..
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
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.
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.
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
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://www.homemade-circuits.com/2012/11/making-40-watt-led-emergency-tubelight.html
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
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.
Can i charge 12v lead acid battery by directly connecting to 20v solar panel without charge controller for two days
Are the zener diodes connected in series with the op amps?
yes in series with the output pin
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
it's for enabling an automatic switching ON of the LEDs in the evening and switching it OFF when day breaks.
Sir good day! I would like to ask for your guidance on how to make a streetlight project where it turns on at night and off at daytime ( I supposed I will used and LDR? not really sure) also the requirement is:
a. the street light project can be dimmed with a potentiometer
b. we should use 20 pieces of 10 watts LED bulb with a voltage supply of 220VAC and the circuit must turn off automatically if there is an overload.
I hope you can help me sir in creating and designing a circuit for my project. Thank you so much!
Hi Gerald, If you use a readymade driver for the LED then it cannot be dimmed with a potentiometer. If you make an external LM338 based driver with an SMPS adapter as the supply source then it may be possible to add the dimmer effect.
The LDR stage is not difficult, and can be implemented by using the following designs:
4 Automatic Day Night Switch Circuits Explained
With LM338 overload protection will be also available
Sir I’m so sorry but I don’t get what you mean. I’m new to this electronics stuff. I mean can you help me design using the 20 LED bulb having a specification of 10 watts each? I can’t visualize it’s schematic diagram. I hope you could help me
Gerald, please specify the voltage and current ratings of each bulb?
20 pieces of 10watts LED bulb with a voltage supply of 220VAC. That’s the only specification given. We should not use any microcontroller or programmable components.
A 220V LED module cannot be dimmed externally, but It can be switched ON/OFF during day and night automatically by using any one of the concepts presented in the following article:
4 Automatic Day Night Switch Circuits Explained
Also sir we are not allowed to use microcontroller or any software programmable component for this project. I would like to ask for you help in making this schematic diagram especially using 20 pieces of 10watts LED bulb with a voltage supply of 220VAC. It must:
a. Turn on at night time and off at daytime
b. Can be dimmed by potentiometer
C. Turns of automatically if there’s an overload
Hoping you could help me because this will be passed in a few hours. Thank you so much sir!
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….
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://www.homemade-circuits.com/2011/12/how-to-build-dual-solar-tracker-system.html
Can you tell the wattage of the components in your design?
What is a good source to order parts?
mthssolarguy@gmail.com
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.
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.
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..
BR, you can try the following concept
https://www.homemade-circuits.com/2017/01/universal-battery-charger-circuit.html
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
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
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.
sorry Matty, I cannot diagnose a simulators results, if you are trying it practically then I may try to guide you through the steps.
Good day Sir,
Will using a 40W solar panel be alright with a 12V/38 Ah battery?
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
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.
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.
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.
Good day Sir,
Thank you.
you are welcome!
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
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://www.homemade-circuits.com/5v-pwm-solar-battery-charger-circuit/
a easier but crude method is to use an LM338 circuit as shown below:
https://www.homemade-circuits.com/how-to-build-solar-panel-voltage/
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.
No changes will be required in the circuit, you just have to reduce the number of LED chains accordingly to achieve the required specs
Sir only low voltage relay is triggering all the time as I adjust p1 and p2 nothing happens at the relay while providing 20 v dc at the solar point while batt not attached also by by varying p3 with in low and high cut out voltage, I used 200k preset for p1 and p2 insted of 10k is it a cause of the aforementioned problem.
Thomas, it means your A1 opamp has some problems. Initially keep the preset at ground level and with the full charge voltage (14V supply) input slowly adjust the A1 preset such that the (+) input pin of A1 just goes over the (-) input pin of A1. When this happens A1 output must go high.
Please replace Z3, Z4 with LEDs which will help you to understand the switching actions of the opamps.
200K is not recommended but still it should work
Thank for your attitude towards responding towards answer ing the query with in due course of time. I done a serious mistake in the circuit that I didn’t tied A 1 preset one arm to Vcc, now the comparator functioning Correctlly and I can able to set high and low voltage cut off. I replaced p1 and p2 with 10k as per design.
Thank you Thomas, Glad you could troubleshoot the issue. Please keep up the good work!
In the pwm led driver the 555 ic getting heated in normal operatig condition is that normal or is there any error in circuit design.
It is not normal, it will heat up only if voltage exceeds 15V or the output pin#3 is short circuited. Please check your IC connections. Pn#2 and 7 are not connected.
Sir, Thank you for quick reply. I my circuit i used 100ohm resistor instead of 4.7 K between pin3# of 555 ic and the tip122 transistor it merely act as a short and I didn’t connect pin2# and pin6# of the ic together now the ic is not heating any more also I can control the time period of pwm o/p. Thank for your patience and valuable time for aswering to my query even though I had made mistakes.
Thank you Thomas, connecting pin#2 and 6 is crucial and they must be connected together for this application. I think there could be some other issue with your design. At pin#3 please increase the value to 1K or any other higher value, 100 ohm is very low.
Thank you Sir , I corrected everything as you mentioned, now it was working fine without connecting trigger and discharge,ICcan’t work as pwm signal generator, Thank you for figuring out my mistakes within your working hours Have a great day ahead!.
You are welcome Thomas!!
hi Swagatam,
can you provide a circuit to operate a led street light will using solar panels with batteries to charge it , 120 watt, and what the use of it? and what the cost , i need 250 pcs
Hi Walied, the above circuit has all the specified features and probably will suit your needs. I can create a prototype for you as per the terms explained on this page:
https://www.homemade-circuits.com/hire-us/
The description looks so theoretical in my eyes . especially the circuit diagram. So compact, complex and confusing, not knowing where to begin from building a prototype on your own. Could you do a video with a step by step ; circuit by circuit until the end. I really want to do this.thank you.
It is a thoroughly tested project, and very easy to build. If you are totally new to electronics then I am afraid this project may not be for you. If you have any specific questions you can ask, I’ll clarify them concisely for you.
Hi. I am a Senior High School student . Our research is the same as you, but we are using photoresistor and LED bulbs. our goal is to decrease or increase the light in LED Bulbs depending on what the sensor(photoresistor) can detect in an environment(Ex. If your LED bulbs is bright and the environment is slightly dark ,the Led bulbs will decrease its light because of the photoresistor and it will balance into the environment) and it can also save more energy because we are using LED Bulbs. Our problem is that we do not know how to write a procedure in making our research and we do not know how to program a code in our research. If you have time will you please help us in making a procedure and a program code of our research.Please reply soon. Thank You
..
Hi Mr. Swagatam. I am Tristan the same person that you’ve been taking with. Yes We are not using arduino We just really need the procedure of making our research.Please reply soon. Thank You
Hi Tristan,
you can try the “Light Controller” circuit discussed under this post
https://www.homemade-circuits.com/ic-lm338-application-circuits-explained/
replace the phototransistor with an LDR! And replace the bulb with a LED. However with LDR the 2K might need some modification. Use a 10K initially instead of 2K, and use a 12V LED for the LED. Yhe input can be anywhere between 14V and 18V fixed
Thank You Mr. Swagatam. If you have time can you please make a procedure on the research we are making so that we can start assembling our circuit and Mr.Swagatam can you recommend us a person that can help us in making a program code of the research we are making. Thank You for your time.Please reply soon.
Hi Tristan,
sorry for the late reply, however it will be difficult for me to provide a write-up about of the procedure due to lack of time. Briefly, you just need to connect the LDR and the lamp in the shown position with the LM338 IC, and then adjust the R1 resistor value until you get the best possible optimization.
You can contact me for more info you get stuck somewhere!
Hi Mr.Swagatam. Thank you for fast reply. if you have time can you please do it. I will wait for the procedure we really need your help.Please reply soon. Thank you
Hi Mr.Swagatam. Thank you for still replying. if you have time can you please do it. I will wait for the procedure we really need your help.Please reply soon. Thank you
Hi tristan, the procedure is actually very simple, and I have already explained it to you in the previous comment, can you please tell what you did not understand in the explanation?
Hi Mr. Swagatam thanks i got it now. Mr. Swagatam may i ask if its okay to you, can you be our consultant in our research. Thank you
Sure tristan, you can post your queries or doubts here, I’ll make sure they are solved appropriately…
Hi Mr. Swagatam. Can i ask you a question, is it free to be your consultant? We dont have to pay you anything? Thank you.
Yes, It is free here!
Thank You Mr Swagatam. Mr Swagatam what are the materials we are going to use? Thank you
Tristan, please post this question under the article which is relevant to the question, I’ll solve it for you!
Hi Mr. Swagatam. Can we do our circuit without the lm338 IC? . we just want to use only transistor, capacitor and resistor only we dont want to use regulators. Thank you please reply soon
Hi tristan, try this circuit
https://www.homemade-circuits.com/wp-content/uploads/2019/08/light-optimizer-solar.png
Thank you Mr. Swagatam this is perfect. Can you show us the procedure of making this circuit and can you please tell us what are the materials we are going to use? Thank you again.
Hi Tristan, please build exactly as shown, resistor is 1/4 watt, parts is given in the diagram. It’s an emitter follower circuit:
https://www.homemade-circuits.com/emitter-follower-transistor-application-circuits/
Ok i will follow exactly the picture of the circuit that you’ve shown to me.Thank you again Mr. Swagatam
No problem!!
Hi sir
Do u have Automatic 40 Watt LED Solar Street Light Circuit pcb layout.if u can pls send me.
thanks
Sorry Samantha, PCB was not created for this project, it was built on a general purpose board
Sir I m interested in solar field so I like your 40W solar led charge controller circuit Sir I m getting some issues one major being I m not getting lower cut off relay to NO on solar i.e. during day I m getting battery output of 1.9 V max which should be some where around 12V cut off is on 5.8V for lower cut off relay & 7.9 for higher cut off relay.
Dweep, sorry I could properly understand your problem, however you can refer to the new updated design which i have posted just below the first circuit diagram, hope this new design will make your job easier to implement.
Sir can I use this charge controller for solar inverter also
Yes you can!
will you please desgin the circuit using the MOSFET or any switching devices instead of Relay if possible.I want to design the predetermined watt of led and how can i specify the require current from Battery size. In your circuit you have explained about the protection of battery during charging of battery from panel and is in charging stage as long as the solar panel falls on threshold light intensity and does the led light switch on from battery mode when the solar panel does not receive enough light in panel ?
can you add color led to indicate 1. the battery is charging
2. the battery is full charged
3.the battery is low
It will require some thinking to create MOSFET version, if possible I’ll update.
You can add a blue LED in series with the bottom 3V zener in the second diagram for getting the solar panel ON indication.
battery low and full LEDs are already given
good morning Sir.
kindly help me with the link to full explanation of this circuit 40watt solar street light using only transistor.
https://www.homemade-circuits.com/wp-content/uploads/2016/12/solar2Bcontroller.png
Hello Ngang,
the full explanation can be found in the following article:
https://www.homemade-circuits.com/how-to-make-solar-battery-charger/
good day sir,
i can’t still find it at the link you have given. the explanation i am asking for is that of a 40watt transistorised solar street light.
Hi Ngang, please see the 7) design, it is same one which you are looking for.
hello, Is it alright if we asked for the proteus file of the circuit diagram?
Hi, I have built and tested this circuit practically, I did not do any Proteus simulation.
Hello sir! while simulating on proteus, we cannot find a relay coil as component. do you have an alternative for the relay coil? and if using relay, how should we connect it to the circuit?
Hello Ailee, I am actually not sure how the Proteus problem can be solved, but the above circuit is a tested design, it will work practically.
when does the red led light turns on? In our proteus circuit, the only led that lights up is the blue led light. *we removed the IC555 stage.
Red turns ON during day time when the 555 LDR is illuminated. If you remove the 555 stage then the red LED will become meaningless. This circuit is fully tested but it is recommended only for the experts in electronics. You must test the circuit stage-wise, not all together.
I am a beginner electronics hobbyist, very interested in solar-powered lighting projects. I appreciate your free tutorials! Thank you so much!
You are most welcome, feel free to ask if you have any further questions