Hello, I'm an A-level student doing a project which involves making a basic light circuit. My objective is to create a solar-powered circuit (2W) with 14 LEDs in a parallel circuit (which I plan to then add to a 3D-printed model). At the moment, I'm planning how to construct the circuit. I have bought LED lights with 20cm wire for each one and a 2W, 5V solar panel with built-in crocodile clips - I wondered if anyone had any advice on how I could attach 14 LEDs to one solar panel, being as efficient as possible? Thanks!

 

What are the specs on these 14 LEDs?

 

Hello - thank you for responding. They are 3V and 15/20mA each

 

For a 5 volt solar panel each LED would need its own current limiting resistor and all wired in parallel.

 

Thank you so much!

 

No battery?

 

Hi thanks for the response. No, not using a battery as it a short term project to present a model.

 

Hello, I'm an A-level student doing a project which involves making a basic light circuit. My objective is to create a solar-powered circuit (2W) with 14 LEDs in a parallel circuit (which I plan to then add to a 3D-printed model). At the moment, I'm planning how to construct the circuit. I have bought LED lights with 20cm wire for each one and a 2W, 5V solar panel with built-in crocodile clips - I wondered if anyone had any advice on how I could attach 14 LEDs to one solar panel, being as efficient as possible? Thanks!

Hi,

When you say "being as efficient as possible" do you mean keeping the solar power to electrical power efficiency as high as possible?
In that case, you have to know the characteristic voltage of the LEDs so that you can get the voltage to be close to the max power point voltage of the solar panel. That might mean just one LED per string, or you might have to connect two or three in series then those series strings in parallel. That would be the case with Red LEDs. With white LEDs, you would probably just have all of them in parallel. If the max current of the solar panel does not exceed the max current of the LEDs, then you might get away without any resistors. If not or if the characteristics of each LED are different, then you either need one series resistor or a bunch of series resistors to balance the current through each LED.

When doing it this simple way, there's no way to get a higher efficiency without using a buck regulator circuit, and/or possibly a max power point tracking (MPPT) circuit. An MPPT will keep the power at a maximum provided the LEDs can always take the max power at full solar intensity.

 

Thank you, this was really helpful. Following your advice, I went for white LED's in parallel (and I didn't need any resistors). The circuit turned out successful, I really appreciate your help.