I bought a pack of OEM mini solar panels that produce 4.2v and 22mA and I was just wondering how many LED's I could hook up to one mini solar panel? I currently have one green LED with a resistor on the one panel but was wondering how many I could possibly run off of one panel?
You need to answer that by designing circuits to provide each LED with its specific voltage and current requirements, and then see how many you can supply.
Typically LED's run off low voltage and 20mA or so of power (it depends what kind of led you have). That being said if one of your solar panels only provides 22mA of power then your circuit would have to be a series circuit for you to connect more than one. In a series circuit the current supplied of 22mA will go through each LED whereas a parallel circuit the current would be divided for each subsequential led. So in your case i can see you getting away with 3 or so led's before the voltage drop across each led will cause the voltage to be insufficient enough to drive anymore. Keep in mind the LED's will turn on but the first one will be bright then next one not as bright and so on. If you opted out and bought a solar panel with 200mA and 4V you could wire the led's in parallel and get 0 led's to turn on with the same brightness or intensity. Hoped that helped!
