A 20v - 0.5a solar panel to deliver 5v 1a or 2a

Thread Starter

Jonathan Bueno

Joined Jan 29, 2023
Hello everyone !

I'm planning to buy a 30w solar panel to attach to my two redundant powerbanks that will be constantly powering my rasberry pi which will be connected to the internet too. Such project I would use to plan building a drone too... I think that would be cool.

I have a doubt about the solar panel which says in the specification it can deliver 20v max and 0.5a max. Some people said to me that I can't increase the current output by attaching a 5v voltage switch or a 5v stepdown converter and some people said I can get 1a or 1.5a indeed. I'm confused and don't know what to do because 1.6a output solar panels are much bigger and heavier.

If someone can help, thanks in advance !


Joined Jun 5, 2013
A linear regulator cannot increase the current, it merely wastes the extra power.

A switch mode buck converter can increase the current when the voltage is lowered.


Joined Nov 29, 2005
Just keep in mind a cloudy day can generate only 10% of the panel rated output. The 10Watt capability of yours may be deficient.
The voltage is not what decreases in a solar panel; it is the current the one that decreases in poor insolation, loading the voltage to a point that appears the voltage is the one that gets lower.
A DC converter is what you may need, maaany flavors available.

A random one ----> https://www.aliexpress.us/item/3256803490251878.html?spm=a2g0o.productlist.main.13.7f6bqzFCqzFCrE&algo_pvid=d0612856-8a43-41c9-a150-20c86f4313a6&algo_exp_id=d0612856-8a43-41c9-a150-20c86f4313a6-6&pdp_ext_f={"sku_id":"12000026758383888"}&pdp_npi=2@dis!USD!5.36!5.09!!!!!@211bd93f16750923275878573d0717!12000026758383888!sea&curPageLogUid=j2iglCMHEMWn
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Joined Jan 23, 2018
The ratings are 20 volts MAX and 0.5amps MAX, meaning that the maximum possible power is ten watts. So while if you had a 100% efficient power converter, such as a step-down switching regulator, and the light level was bright enough to give the full ten watts out, you could get 5 volts at two amps.
BUT nothing is 100% efficient. You may be able to get 5 volts at one amp quite a bit of the time, which is half of the maximum. Or maybe less, depending on how hones the claim is. But that is only with adequate sun on the array of cells.