solar power supply to microcontroller by using 12V battery

Thread Starter

vamo

Joined Oct 30, 2020
4
hello,

currently I'm doing a project on public automation garden where the supply is given from solar panel. I got stuck in the middle as i'm missing some components while rigging up a circuit from solar panel to battery.

It will be great help if anyone provides a proper circuit diagram for solar power supply.

thanks in advance
 

Papabravo

Joined Feb 24, 2006
16,830
hello,

currently I'm doing a project on plant irrigation system where the supply is given from solar panel. I got stuck in the middle as i'm missing some components while rigging up a circuit from solar panel to battery.

It will be great help if anyone provides a proper circuit diagram for solar power supply.

thanks in advance
Which of the thousands of possible circuit diagrams would you actually be interested in?
 

Thread Starter

vamo

Joined Oct 30, 2020
4
Which of the thousands of possible circuit diagrams would you actually be interested in?
I don't have proper knowledge on solar energy but the thing required is supply to microcontroller which is 5V.
can you give a circuit diagram which has voltage regulator, 12 battery, converter etc..
 

Thread Starter

vamo

Joined Oct 30, 2020
4
I don't have proper knowledge on solar energy but the thing required is supply to microcontroller which is 5V.
can you give a circuit diagram which has voltage regulator, 12 battery, converter etc..
when we don't know anything it's better to ask someone who knows.
 

Papabravo

Joined Feb 24, 2006
16,830
What you are asking for at the moment is to say the least: less than precise. I could give you any one of those thousands of circuit diagrams, but in your present state of knowledge you would have no way of deciding if it met your requirements. This is like putting the cart before the horse. In order to make your list of requirements we can start with what I think you have.
  1. You have a board, with a microcontroller, that needs a power supply of +5VDC
  2. You have a +5VDC power supply that works off the mains and will power the board to let you do things with it.
  3. You have a 12 VDC motorcycle, automotive, or marine battery that puts out 12 VDC (nominal)
  4. You have a charger for that battery that works off the mains.
  5. You have a solar panel or panels of some description that you want to use to charge the 12 V battery
Tell me which of the five things that I think you have are actually in your possession.
For the items that you have tell me more about each one with links to datasheets or product specification.

There are at least two things missing from this list:
  1. A solar panel to +12 Volt battery charger
  2. A DC-DC converter that will take a DC input of +11-16 VDC and output +5VDC
For the DC-DC converter I need to know how much current you require from the +5V output

From these answers we can go in at least two different ways
  1. You can buy the components you need without ever worrying about the details of the circuits.
  2. You can buy the components and fabricate the circuits for yourself.
I would recommend that if you want to build the circuits yourself you start with something simpler and develop your construction and fabrication skills. You have to learn to crawl and walk before you try to run a marathon.

BTW - this list of questions is not exhaustive; it is just scratching the surface.
 

Thread Starter

vamo

Joined Oct 30, 2020
4
What you are asking for at the moment is to say the least: less than precise. I could give you any one of those thousands of circuit diagrams, but in your present state of knowledge you would have no way of deciding if it met your requirements. This is like putting the cart before the horse. In order to make your list of requirements we can start with what I think you have.
  1. You have a board, with a microcontroller, that needs a power supply of +5VDC
  2. You have a +5VDC power supply that works off the mains and will power the board to let you do things with it.
  3. You have a 12 VDC motorcycle, automotive, or marine battery that puts out 12 VDC (nominal)
  4. You have a charger for that battery that works off the mains.
  5. You have a solar panel or panels of some description that you want to use to charge the 12 V battery
Tell me which of the five things that I think you have are actually in your possession.
For the items that you have tell me more about each one with links to datasheets or product specification.

There are at least two things missing from this list:
  1. A solar panel to +12 Volt battery charger
  2. A DC-DC converter that will take a DC input of +11-16 VDC and output +5VDC
For the DC-DC converter I need to know how much current you require from the +5V output

From these answers we can go in at least two different ways
  1. You can buy the components you need without ever worrying about the details of the circuits.
  2. You can buy the components and fabricate the circuits for yourself.
I would recommend that if you want to build the circuits yourself you start with something simpler and develop your construction and fabrication skills. You have to learn to crawl and walk before you try to run a marathon.

BTW - this list of questions is not exhaustive; it is just scratching the surface.
thanks for your explanation.
my project has microcontroller of 5VDC, DC motor of 12VDC, and a battery to work during night times, a converter and voltage regulation.
and also what rating of battery can be used so that battery stores energy to work during night time?
will it be effective if i use buck-boost converter?

can you suggest a circuit diagram for this required details?
 

Papabravo

Joined Feb 24, 2006
16,830
Let us talk about batteries for a moment. The typical automotive battery is designed to provide a very large current ~600 amperes to turn a starter motor for say 30 seconds to start the engine. These batteries perform poorly when asked to deliver a small current for a long time. The battery type you should be looking for is a deep cycle marine battery. This type of battery is designed to provide a modest current for a long time and can be discharge to a much lower voltage without damage. This technology is well established and well understood. Chargers are available for a nominal price.

There are more exotic battery technologies, like those used in power tools, which will be more expensive and require a more sophisticated charger.

You can find online "Battery University" where you can educate yourself about battery technology. After doing that I would acquire two batteries and a charger for those batteries. Then you can experiment with how long it takes to charge the battery and how long it can be used to run the motor, either continuously or intermittently. Then you will have some experimental data that you can use to refine your requirements.

Good Luck.
 

Dodgydave

Joined Jun 22, 2012
10,050
Ok what battery are wanting to use will dictate the type of charger, then how much voltage and current your solar panel will give out..
 

bassbindevil

Joined Jan 23, 2014
171
There are "solar charge controllers" with built-in 5V USB outputs, and an LCD (displays battery voltage) about $10 on ebay. The charge controller regulates the power from the solar panel so it doesn't overcharge the battery; they usually also have a switched output which can turn on lighting automatically. If you already have a basic charge controller with no USB outputs built-in, wire a car lighter jack to the battery and plug in a USB car adapter. These charge controllers are designed for lead-acid batteries, like a car battery or sealed-lead-acid "gel cells".
 
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Dekzion

Joined Feb 9, 2021
3
Totally agree Bassbindevil, There's certainly no need to over think things. using a standard min 60 amperes car battery and you're good to go with just about every solar controller on the market. and a clip on cig lighter socket completes the job
 

Yaakov

Joined Jan 27, 2019
3,520
Totally agree Bassbindevil, There's certainly no need to over think things. using a standard min 60 amperes car battery and you're good to go with just about every solar controller on the market. and a clip on cig lighter socket completes the job
As noted previously in the thread, car batteries are designed to produce short, high current power not long small current drain. They are poorly suited to this application.

Deep cycle marine batteries, on the other hand, are designed to handle this much better and other SLA batteries are also well suited. Car batteries are great for cars, they’re less than optimal for low power applications in spite of their apparently high ratings.
 
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