Voltage Regulator for 30W solar

[goodjboy]

I want to build a voltage regulator that can handle 30 watts of power input and output with input voltage around 17 volts and an output voltage of 5 volts.

I have a 30watt solar panel and I want to power a bunch of 0.5 watt USB AA battery chargers with it.

I know about the 7805 voltage regulator from Radio Shack but I am not sure how efficient it is. It looks like that regulator can handle up to 5 watts. My thoughts were to build 6 7805 regulators and have the panel feed them all and then have all the regulators feed by chargers. Is this an efficient solution or will I lose a lot of energy to heat this way? Is there a better way to do this?

I would greatly appreciate any help my fellow geeks have to offer.

Thanks!

 

[BobK]

Using a 7805 to go from 17V to 5V is only 29% efficient.

A better solution would be a DC-DC converter. These are much more efficient. You can get them as modules or look for a switch mode regulator and build it yourself.

Bob

 

[goodjboy]

I searched on "switch mode regulator" and found this cheap one that can handle 15watts but I am not sure if it is just a regular inefficient voltage regulator and the more efficient one you are talking about. What do you think?

http://www.hobbyhot.com/HOBBYWING-3A-Switch-Mode-UBEC.html

 

[BobK]

It looks reasonable. Any switch mode regulator should be far more efficient than 7805's.

Bob

 

[goodjboy]

Thanks!

Thanks so much for your advice. I just ordered 2 15Watt units for like $15. I am going to hook these two in parallel with the solar panel and hook in a bunch of the USB AA battery chargers to them. Thanks again...