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.
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
Gokul says
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.
Swag says
No changes will be required in the circuit, you just have to reduce the number of LED chains accordingly to achieve the required specs
dan says
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
Swag says
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/
VIVIAN says
Good day Sir,
Thank you.
Swag says
you are welcome!
VIVIAN says
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.
Swag says
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.
Swag says
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.
Matty says
Good day Sir,
Will using a 40W solar panel be alright with a 12V/38 Ah battery?
Swag says
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
Matty says
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.
Swag says
sorry Matty, I cannot diagnose a simulators results, if you are trying it practically then I may try to guide you through the steps.
Anonymous says
Hello sir,
Thank you, so will 36 white LEDs be good enough for approximately 2000 lumens.
Swagatam says
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
Anonymous says
Hello sir,
the 40W is it the solar panel rating that should be used the total output power of the LEDs, is the 1.2A referring to the overall current through the LEDs or through one. do I use 36 LEDs for approximately 2000 lumens. what is the current though and voltage across each LED.
Swagatam says
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
B R prabu says
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..
Swagatam says
BR, you can try the following concept
https://homemade-circuits.com/2017/01/universal-battery-charger-circuit.html
Anonymous says
Sir!i have some problem to understand the "Ambient Light Detector Circuit"part.which mode is it?There is "R" B/n pin 5 and pin 7.Is it because to prevent pin 7 being damaged as it shorts to 0v ?why at all pin 5 connects to pin 7 and why pin 6 too connects to Vcc?would you mind giveing me more explanation?
Thanks in advance.
Swagatam says
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.
mthssolarguy@gmail.com says
Can you tell the wattage of the components in your design?
What is a good source to order parts?
mthssolarguy@gmail.com
Swagatam says
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.
Preeti says
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….
Swagatam says
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
Unknown says
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
Swagatam says
it's for enabling an automatic switching ON of the LEDs in the evening and switching it OFF when day breaks.
sanjana ghosh says
Are the zener diodes connected in series with the op amps?
Swagatam says
yes in series with the output pin
Umesh Kudale says
Can i charge 12v lead acid battery by directly connecting to 20v solar panel without charge controller for two days
Umesh Kudale says
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
Swagatam says
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.
Ous says
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
Swagatam says
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
NAUTY says
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.
Swagatam says
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.
Preeti says
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
Swagatam says
you will require a 18-20V/5amp (minimum) solar panel, and a 12V 60AH (minimum) battery
Preeti says
thank you so much sir for replying….
?☺☺☺
Swagatam says
you are most welcome Preeti!
Preeti says
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…..
Swagatam says
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
VJ Gopal says
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
Swagatam says
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.
VJ Gopal says
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
Swagatam says
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
VJ Gopal says
hello sir, what are the modifications to be done for an LED module output power of 15 watts. Thanks
Swagatam says
you can use the same set up, no changes would be required
Arif Khan says
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)
Swagatam says
I can ask your specific questions, I'll try to solve them…
M.Suresh kannan says
Sir
May i know basic design calculation of solar system.
I am new for this design
Please help me
Unknown says
Sir what is the value of C1
Swagatam says
C1 can be a 10uF/25V cap
Unknown says
Sir what component should i replace for 18W,24W solar Steet light
Swagatam says
you don't have to change anything in the circuit design, just reduce the number of LEDs in the LED panel proportionately
Unknown says
Thanku Sir
Unknown says
Sir what is R9 value is it 22M and R7
Swagatam says
R9 = 2.2Meg
R7 = (0.6 x 10) / Battery AH rating
Unknown says
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
Swagatam says
(+) is pin#3, and (-) is pin#2
Mohamed Ashiq says
Battery value is 12 V 26amps. R7 value is 2.6 Ohms. Its correct or not
Swagatam says
battery is correct, R7 = 0.6 x 10/26 ohms
sampath says
sir please send how to connect relay 2 nc,no and common pins
Swagatam says
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
Ous says
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
Swagatam says
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…
Ous says
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
Satish Vekariya says
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
Swagatam says
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
fasat2112 says
Thank you Swagatam.
BR
fasat2112 says
Hello Sir,
I need only LDR modul with IC555 for switching on/off with night or day. How to design circuit?
Thank you
BR
Swagatam says
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
Dipto says
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.
Swagatam says
Dipto, you can ignore this relay stage, it's not relevant to the twin battery charger design that you are presently building
Mahesh K Thakur says
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.
Swagatam says
hello Mahesh, please mention the exact specifications of your requirement.
Jayaraju Lakkepogu says
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…
Swagatam says
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
Jayaraju Lakkepogu says
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
Jayaraju Lakkepogu says
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
Swagatam says
Thank you! presently I do not have this design, I'll look for it and let you know as soon as I find one.
Swagatam says
for a 12V5amp smps driver you can try this one:
https://homemade-circuits.com/2014/03/12v-5-amp-transformerless-battery.html
Jayaraju Lakkepogu says
Hi I need solar LED streetlight circuit with dusk to dawn operation using microcontroller. Can u provide?
Swagatam says
hi, presently I do not have this design, I'll try to find and let you know.
Ous says
Please let me know if you find it as am interested as well, with heat sink or cooling system
Jayaraju Lakkepogu says
Heat sink only. When can I expect this? if u have pls. contact to my mail ljayarajuatgmaildotcom
Swagatam says
you will need an aluminum base PCB for this circuit
jeke j says
Hi,
I want assembled prototype of this street light, how can i get it from you.
my email: jeke117@gmail.com
Thank you
Swagatam says
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.
Ashok Dhenge says
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?
Swagatam says
yes it should be without any battery connected, the variable inputs simulate the battery threshold levels and is used for setting the relevant presets.
Ashok Dhenge says
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….
Swagatam says
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.
Ashok Dhenge says
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…
Swagatam says
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.
Ashok Dhenge says
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
Swagatam says
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
Ashok Dhenge says
another question is what type and size of cables are used from solar panel & charge controller to load is used?
Swagatam says
it will depend on the current specs of the system.
Ashok Dhenge says
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?
Swagatam says
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
ashokagreatking06 says
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.
Swagatam says
yes it can be used, please provide all the details regarding your requirement? I'll try to figure out the procedures.
Ashok Dhenge says
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?
Swagatam says
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.
Ashok Dhenge says
Hi sir
There is LM 338 ic1 not available in local area any equal part please help me?
Ashok Dhenge says
can we use LM 317/LM350?
please give me specification of LM338
Swagatam says
LM350 can be used, but will require a larger heatsink than LM338.
Ashok Dhenge says
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?
Swagatam says
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.
shiva prasd says
Its ok there is no r2&r6, what should be r7 fr above prescribed values
Swagatam says
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
shiva prasd says
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
shiva prasd says
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,
Swagatam says
provide battery ah??
where's r2, r6?
K Thakur says
can u tell the pcb connection for this
ples share the link
shiva prasd says
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
Swagatam says
you can refer to any online "breadboard tutorial" site, there are plenty of them.
Umer Ilyas says
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???
Swagatam says
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.
surya kiran says
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)
Swagatam says
the above circuit can be used with the specified components
Ous says
Thank you, will get in touch as i progress along
Ous says
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
Swagatam says
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.
Anonymous says
Hello dada,
I want to make this circuit as a emergency light for my village house because of huge power cuts.
I had also made a semi automatic solar charger Iam uploading its image on facebook.
and how can we modify this circuit to so that is charges the battery via the solar panel and it switch on the LED bank when the grid power supply fails and the sun goes down.
(I think the concept which I used in my LED Emergency light transistor BD140,can work and power it by Transformer less power supply ).
Can You explain how the IC 324 works?
please help
Thanks,
Tanmoy
Swagatam says
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.
Anonymous says
thanks dada for your quick reply.
Anonymous says
can i know if this circuit is working
Umer Ilyas says
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.
Swagatam says
where do you want to use BC547?
BC547 can handle only upto 100mA
Anonymous says
Dada
Ic 324 consists of 4 gates and 14 pin so in the circuit can we use a single IC 324 for the complete purpose of the circuit.
Tanmoy
Swagatam says
yes only a single is required here.
Swagatam says
yes LM196 or 396 will be fine.
Swagatam says
a single 324 IC is used here.
Umer Ilyas says
you forgot to mention value of C1 capacitor
Umer Ilyas says
ic 324 have 4 comparator in one ic can single ic be used???
Umer Ilyas says
lm338 is not available in my area. any 15v 5a supply will be fine i guess in place of lm338
Umer Ilyas says
can lm396 be used in place of lm338. it supply 10 ampere
siva raman says
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?
Swagatam says
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.
siva raman says
sir LDR equal resistor value?
Swagatam says
use 1M for R10 and then focus some light on the LDR, check the the output LED response.
siva raman says
sir circuit connection couplet, 555ic section not work , p1 p2 aliment confused , led relay not work help me what my mistake
siva raman says
sir circuit connection complet, 555ic section not work, p1 p2 alinment confused, led relay not work, help me
Swagatam says
can you bring the circuit to me, i'll show you what faults you have made….
siva raman says
sir, i am siva the circuit connection complet.
555 ic section not work, led o/p relay not work what my mistake
kishen singh says
i used lm 350 bt the output is low
hw to adjust the output in the voltage regulator
Swagatam says
make P3 = 10k
siva raman says
sir, this circuit connection couplet, 555 ic section not work, battery low full position confuse led o/p relay not work help me
kishen singh says
Sir how to adjust p1 and p2 values nd my battery is of 18ah so what will b value of R7
Swagatam says
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.
Umer Ilyas says
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???
Swagatam says
With a 26ah good condition battery it will take around 10 hours to discharge.
R10 can be replaced with a 1M fixed resistor.
Swagatam says
I'll update the circuit soon with the LED indicators.
kishen singh says
Thanks can we use lm 350 since its current rating is 3A
Swagatam says
yes, will do.
kishen singh says
Any substitute for lm 338
Swagatam says
sorry no identical substitute.
Anonymous says
what type of led you are using in this article??
Swagatam says
1 watt/350mA/3.3V
siva raman says
sir R6,R7 VALUE confused calculation please 60ah battery
Swagatam says
R7 = 0.6/6 = 0.1 ohms
don't use R6, replace it with a wire link.
siva raman says
Thank you so much sir, I'll try and get back to you Thank you and Good Night
siva raman says
Thank you so much sir, I'll try and get back to you, Thank you
siva raman says
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
Swagatam says
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.
Anonymous says
sir,im working on mppt project
kindly help me with the battery selection
Swagatam says
what is the rating of your solar panel? Battery rating will need to be calculated according to it.
Anonymous says
hi sir. wat is the voltage value of the capacitor?
Swagatam says
50v
Anonymous says
Hello sir, can you please tell me where to connect the led indication for knowing whether the battery is charging or not?
Swagatam says
please refer to the following diagram:
4.bp.blogspot.com/-mJfdYOcXCzs/UJ3VJD8ygFI/AAAAAAAABQw/_kGCNyHxiW4/s1600/smart%20battery%20charger%20circuit.png
Anonymous says
can we use any LDR??
Anonymous says
Hello Sir
I have a 40 watt solar panel and 12v,30AH battery and want to make this circuit, so can i used this ratings for this circuit.. looking forward for ua kind suggestion..
Swagatam says
Yes you may go ahead with it, it will work.
Anonymous says
Thank you sir.
Sir for the value of R6 the formula as u have given in other blog its 0.6/R6 = 1/10 battery AH
That means for my 12v30Ah R6 will be 0.2ohm only? Sir i am a bit confused with it…
Swagatam says
yes your answer is absolutely correct.
Anonymous says
hello sir
According to my battery AH i.e 30AH,after calculating R6=0.2ohm,since it s not availabe in the market, i tried 5 1ohm's in parallel also bt due to tolerance and all it used to cum around 0.6 ohm so i am so confused, is there any way to use R6??
Swagatam says
sorry there's no other way to do it. putting a resistor is the only option.
Anonymous says
Sir, I have connected everything as the above circuit except that instead of R6=0.2ohm(as i have mention in the above comment) i used R6=0.6ohm and when i try to make the output voltage to nearly 14.3volts by adjusting the P3 i can't make it less than 16volts or else p3 start burning, the input voltage from the panel is 19volts… Is that because of R6?
please looking forward for your valuable sugestion….
Swagatam says
that should not happen, there may be a big mistake somewhere, check the LM338 pinout connections.
even without R6 (replaced with wire link)), the preset will never burn in any position.
the voltage should vary right from 1.25 to the maximum level (19V)
Anonymous says
Thank you sir, its coming. I think there was something wrong with the preset connection or preset itself, after i changed the preset with new one its coming as u said i.e from 1.25 to the maximum level (19V). I have some querry sir
1) the o/p current is coming approx. 8Ampere, is it ok or it should be limit to 4 t0 5 Ampere, if so than how sir?
2) As u have said "For better indication replace the 1N4007 diodes a the outputs of A1 and A2 with LEDs.Now apply input voltage to the circuit, adjust P3 to generate 14.3V, and adjust P2 such that the LED at the output of A1 just lights up fully", i did that sir but the Led doesn't light up at any point…
3) The battery used to get charge from the charging circuit without connecting the other part i.e Ic724 part, but when i connect the battery does not charge at all…
Swagatam says
Make the stages separately, first make the LM338 stage only, adjust R7 so that only the desired amount of current is allowed at the output.
Next build the last circuit shown in the following link:
https://homemade-circuits.com/2012/11/making-40-watt-led-emergency-tubelight.html
I will explain how to proceed after you have built it.
Anonymous says
can u tell me whats the value of capacitor across R10
Swagatam says
use a 10uF/25V
Anonymous says
Hello Sir what will be the cost of this complete project. kindly mail it to my id aier1990@gmail.com
Swagatam says
around Rs200/- or $4 excluding solar panel and battery.
jp8rock says
hi
i want to make a automatic solar charge controller for 12V 40ah lead acid battery having 9W load to operate. and i'm having panel of 18v 2.5A. please suggest me circuit my email jp8rock@gmail.com
Swagatam says
Hi,
You may try the above explained circuit, the IC1 stage along with the lower relay, D2,R4,and T3 won't be required, they all may be eliminated..
mohan rao says
I want to know the rate of this finished product of yours. Kindly mail to my email id mohanrao_70@yahoo.com as well as other products which will be helpful for my own use.
Swagatam says
will it be on a regular basis (quantity) or just a single piece? because i won't be able to sell single units
Anonymous says
Just for the curiosity, can I use high power 3 watt leds instead of 1 watt in this circuit since the Vf for both 1 watt and 3 watts are within your calculation to arrange 3 leds on series and if this idea of PWM utilize very low current to illuminate the leds, it should not be the problem (despite the full current for 3 watt led is 700mA)? If I can use 3 watt leds, is there anything I need to modify on the circuit? Thanks.
Swagatam says
Yes you may do it. No modifications would be required, the transistor might require a bigger heatsink though.
Anonymous says
I don't understand how you derived "Current Consumption: 1.4 Amps @13 volts, and 1.2 Amps @12V" on top of the page under the title LED Lamp Specifications. My understanding was 1watt led has 350mA current rating, that doesn't add up just the 1.2 or 1.4Amp, please teach me correct way of calculating.
Swagatam says
first of all here we are not driving the leds at full 350 mA, and is not recommended.
the IC will generate pwm pulses which will keep the leds illuminated for only 50% of its total illumination period.
therefore the effective consumption becomes 39/3(series) = 13 x 0.2(current) = 2.6amps/2(50%) = 1.3 amps.
I hope you got it now.
Anonymous says
Also, I would like them to automatically turn on at dusk and turn off at dawn (like these tiny solar garden lamps do which have light sensor diodes but read somewhere that circuits made without these sensors to make dusk to dawn are better than with sensors, unfortunately, the author does not elaborate why).
Swagatam says
You may refer to the second circuit that's shown in the following post, it uses an LDR for the required detection which is probably a better option than photo-diodes:
https://homemade-circuits.com/2012/08/led-emergency-light-circuit-with.html
Anonymous says
I bought six solar garden lights from the store hoping they will illuminate my pathway and garden. However, these tiny chinese made solar lamps (it has one single 5mm led) produce only very little amount light like a firefly even with the full charge. Each lamp has only one 1.2v 600mah battery and the tiny solar cells are attached to the top of the lamp. On top of that I did not realize some parts of my garden get only 1 or 2 hours sunlight. Could you PLEASE help me to design a circuit that one solar panel (let say 3 to 5 watt) can safely (auto cut off when overcharges) charge some Li-ion 3.7v 3000maH (18650 type) or Sealed Lead Acid battery and then this power can be distributed to all 6 garden lamps to light high power LEDs (preferably 1W or 3W) in each lamp? I would greatly appreciate your invaluable time and effort to help me. My email address is mikbh@hotmail.com (please do NOT post my email address on this public domain, if you decide to publish this post). Thank you.
With warmest regards,
Mike
Swagatam says
Thanks!
You can try the SECOND circuit shown in the following article.
You can incorporate any battery between 3 and 12V as per your specs.
https://homemade-circuits.com/2012/07/make-6v-4ah-automatic-battery-charger.html
There's no edit facility here, so cannot remove your email ID….if you say I can permanently delete this conversation.
William Dela Cruz says
Good Evening sir. i just want to ask if what is the value of P3 and R9? is it really 4K7 or 47K ? and the 2M2 or 22M? thanks
Swagatam says
Good evening William,
P3 = 4.7K
R9 = 2.2M
Premdeepak Antony Peedikayil says
I removed the 338 Ic and checked, it is giving an output equal to input, but back in the circuit it gives only 1.4 v do I ve check the BC 547 ic or the should I send the PCB Diagram I made for your consideration Sir, I designed it and asked one PCB Maker to etch it for me . Please … waiting for your reply and also sorry for troubling you so much
Swagatam says
OK, remove the transistor and check, it might be faulty.
Premdeepak Antony Peedikayil says
Res Sir,
I tried your suggestion of replacing the 5K preset to 10k but the output still remains at 1.4v Please Help
Prem
Swagatam says
then something's definitely wrong with your circuit (connections) or the IC.
Premdeepak Antony Peedikayil says
Thank you so much sir, I'll try and get back to you Thank you and Good Night
Swagatam says
…my pleasure!
Premdeepak Antony Peedikayil says
Res Sir,
thanks for this precious circuit, I have made it using LM 338T (part no JM91BR) and gave an input of 17v from an solar panel of 12v 30 w rating. but when checking the volatge it is only 1.4v output, I think I've gone wrong some where, I've used a 5k preset intead of 4k7 preset, is it the problem, or else may be i've used a 220 ohms as R6 and 400 ohms R7, is my calculation wrong, can you tell me exactly what should be R6 and R7 to charge a 12v 26 Ah battery, because I am bad at calculation.Also can I use a LM317T for the same circuit to chagre a battery of 12v 7Ah x 2 in Parallel, please help me sir, thanking you once again
Prem A
Swagatam says
use 10 K preset for P3. rest everything is OK.
LM317 will not charge 2 X 7ah, it can charge only a single 7ah battery.
Anonymous says
sir how many hours its take to charge full battery and how many hours its lights and can we connect 60watt panel and above 12volt 26ah battery?? please help me?
Swagatam says
you can connect 60 watt panel and 12V 26 AH battery to this circuit.
battery should get charged within 7 hours of full sunlight.
Anonymous says
hi sir i need a charge controller for solar street light please help me
Anonymous says
sorry sir , i did a mistake with non-inverting(+)pin of A2 to R2 via a 10K resistor. now it is working well(there is no sound when the low cut off time). perfectly working. thanks for your valuable co-operation.
bala
Swagatam says
OK that's great!
Anonymous says
sir , i did the circuit , it is working fine .sometimes the low voltage cut off relay giving vibration sound, i want to replace the relay ?
Swagatam says
yes, because A2 does have hysteriesis, do these modifications to solve the problem:
Connect the non-inverting(+)pin of A2 to R2 via a 10K resistor.
Next, connect another 100K resistor across the non-inverting(+)pin and the output pin of A2….this will hopefully solve the issue.
Anonymous says
sir
i did all. but little sound has come when the battery voltage is in 11.4 to 11.1 after that the load disconnected .
Swagatam says
reduce the 100k to 10k….
Anonymous says
sorry sir , not solved .
Anonymous says
sir , waiting for your response.
Swagatam says
Can't diagnose it, because a resistor across the explained input and output pins should have stopped the chattering of the relay….
Ram says
Its connected in parallel in output. Using above post I understand few something to avoid heating / short circuit by produced by the shaded cells.
I had info about blocking diodes which we connect in series with battery. Thank you again
Swagatam says
the shaded cells act more negatively compared to the unshaded cells, which generates heat inside the shaded cells due to the formation of negative current.
A bypass diode nullifies the negativity of the cells by allowing current through it and thereby avoiding the heating of the shaded cells.
Ram says
I need help to understand the use of this diode in this solar panel junction box. Purchased 25w 12v panel for some testing and found two diode attached in serial. Please help me to understand. I can take pic and upload if needed. thank you Swagatam for all your help.
t0.gstatic.com/images?q=tbn:ANd9GcQJgYPA4xVui04EOka6sOw1Y_kq_xMjonVl0wOCxYDUrfg6SGhzvSZ-6aqP
Swagatam says
how is it connected, in parallel to the solar panel output or in series??
Swagatam says
Hi Ram, these are Bypass diodes…please read the following post:
www.oksolar.com/technical/diodes_in_pv_systems.htm
Anonymous says
I want to increase the power to 3KVA.I have got 24-0-24V transformer about 5kA. I am intending increasing the FET to 16pcs WITH A HEAT SINK, instead of 2.What other changes should l make to the circuit to achieve the power of 3kVA.Thanks for all your efforts.-Ladipo K.O ,fut, Akure, Nigeria.
Swagatam says
Which circuit are you referring to???
suji says
Dear sir,
What should I use for the opamp.Is it ok 7404.I cant understand how to use the opamp,s pins.pls help me.thanks.
Swagatam says
7404 does not have opamps, as given in the parts list you should use LM324, which has four opamps, any two may be used out of them….
Anonymous says
thank u sir , i will give u feedback later.
Anonymous says
ok sir for battery low indication ?
Swagatam says
across A2 output and ground with 1K resistor.
Anonymous says
dear sir ,
iam going to make this circuit . please tell me where i want to place led for battery full(led green) and battery low (led red).
Swagatam says
across A1 output pin and ground with a 1K series resistor.
Anonymous says
dear sir ,
i have 230 vol a.c 600 va inverter and 12v/100 ah battery for my home to manage power cut. due to severe power cut iam planing to go for solar panels and charge controller. i want to charge my battery in solar panel at day time . here how i can change solar panel and a.c mains. i want to change my inverter ? please suggest me .
Swagatam says
You can try the circuit given in the following article, this circuit will charge your 100ah battery efficiently.
https://homemade-circuits.com/2012/11/high-current-transistor-tip36-datasheet.html
Anonymous says
thank u sir ,
Swagatam says
It's 10K
Anonymous says
dear sir , please mention the R12 value
Anonymous says
ok i will post you after testing the circuit. thank u sir.
Anonymous says
45 watt cfl. works on ac 230 ac volts. i dont want LDR circuit.please suggest me.
Swagatam says
Remove the IC555 and the associated parts for getting rid of the LDR switch circuit.
Connect the points "to LED module" to inverter input supply.
Anonymous says
dear sir , i am bala, i did the circuit without IC 555, iam not able to set the P1 and P2. please explain the alignment method. it will help to finish the project.
Swagatam says
Dear Bala, For better indication replace the 1N4007 diodes a the outputs of A1 and A2 with LEDs.
Now apply input voltage to the circuit, adjust P3 to generate 14.3V, and adjust P2 such that the LED at the output of A1 just lights up fully.
Now reduce adjust P3 to get 11.2V and adjust P1 such that A2 LED now just lights up fully………..your circuit is set.
Anonymous says
dear sir , As per your suggestions i did the alignment it is working fine and project is completed .but i cannot understand the battery full cut off area battery protection , T1 and its relay function. when i give 14.3 voltage to the circuit the charging voltage 13.3 comes to the battery . how the battery it is protected by over charging .
with your help only i am doing all .
please explain sir.
thanks lot
Swagatam says
OK, remove R8 if you want a complete cut off…..
Anonymous says
ok sir , what is doing R8 in that place ,i cannot understand , please explain.
the circuit is working well now.
Swagatam says
R8 is for restricting the battery voltage from falling below 13V after it's been cut off from the charging mode…
Anonymous says
dear sir, i want use this circuit for 50 watt 230 volt load and i dont want the ldr circuit. plese suggest me.
Swagatam says
what is your load? is it AC or DC?
For AC loads you will need an inverter.
Anonymous says
You have shown a Heat Sink, in the immage, i think you have left out a transistor part to be mentioned
Swagatam says
The heatsink is mounted over the IC LM338.
Anonymous says
i dont want the led driver as load i just want to use this design as solar charge controller so what should i eliminate ? please help me
Swagatam says
Please refer the following circuit:
https://homemade-circuits.com/2011/12/how-to-build-solar-panel-voltage.html