circuit for 5v out put using a solar panel

[dheeru kiran]

I have a solar panel of rating 15v and 18+/- 3%w .I get only 70 to 80 mA in the early in the morning and evening , I need to amplify the current to at least 600mA to charge my phone. and should not exceed 1amp in the afternoon .

Can some one please suggest me something that I can do....

 

[dheeru kiran]

I tried L7805 to regulate the voltage .can someone tell me how I can increase the current by reducing the voltage,and maintain the current between 600mA to 1A.

 

[MikeMl]

A linear regulator just reduces voltage without changing the max current available from the panel.

You need a step-down "buck" switch-mode converter with an output voltage of 5Vdc. They are available **broken link removed**...

A typical buck converter is about 85% efficient, meaning that if you put 3W in, you will get only 2.55W out, but when the solar panel is only putting out 3W (15V@0.2A), then you will get 2.55W/5V = 0.51A into the phone...

 

[dheeru kiran]

https://www.amazon.in/gp/aw/d/B00LT...SX110_SY165_QL70&keywords=step+down+converter

Can I buy the above converter ? And the amp rating is 3amps is it OK if the phone is feed with more then 1amps?

 

[MikeMl]

...Can I buy the above converter ? And the amp rating is 3amps is it OK if the phone is feed with more then 1amps?

Should work.


You feed the phone 5.0V. The charge-controller inside the phone determines how much current it requires for charging the battery, but likely never more than 1A. If your solar panel is not capable of delivering as much current as the phone demands, then I'm not sure what will happen, maybe the charge controller will turn off, waiting for a better sun angle...

 

[dheeru kiran]

Can I do some some thing else on my own to increase the current ?

 

[ronsimpson]

Post #4. That should work.
The phone will not take more current than it needs.

 

[MikeMl]

Can I do some some thing else on my own to increase the current ?

Get a 12V Sealed Lead Acid battery of several Ah. Get a charge controller. Use the solar panel to charge the battery when it is not being used to power the phone charger. Use the battery to charge the phone at times you need to when the sun isn't available. Might require getting a second (or larger) solar panel.

 

[dheeru kiran]

OK thank you for the suggestions !!..

 

[4pyros]

If you want to be able to charge your phone at anytime or just store your solar energy, you must use a rechargeable battery.
If you use a 12 volt battery you can use a standard 12 volt to USB charger adapter and not worry about your phone current.