5V Solar panel - Page 1
Forum section: electronics / beginners

author: Kantilo
author_rank: Contributor
timestamp: April 25, 2023, 12:00:07 pm
content: Hello,I recovered a panel of this type, which I wanted to put in a 3D print with a USB connector to be able to plug in phones or other when I am outside, with this type of usb portThe panel delivers 5V, do you know if there is a risk in connecting the devices directly to it?I take adviceTHANKS

author: radiolistener
author_rank: Super Contributor
timestamp: April 25, 2023, 12:12:16 pm
content: Quote from: Kantilo on April 25, 2023, 12:00:07 pmsuch panel will be unable to charge phone, because it has too weak power output.At a glance at high sun exposure it can provide about max 0.5 W which is about 0.5/5 = 100 mA max current which is not enough to charge the phone. In a usual sun exposure conditions it will provide much smaller current.You're needs to use at least 10-20 such panels connected together in parallel in order to charge your phone. And there is needs for voltage regulator between solar panael and USB socket for phone charging.Quote from: Kantilo on April 25, 2023, 12:00:07 pmyes, there is a risk that you can damage your phone. Because it can have higher voltage on the output, and if the phone doesn't apply load immediately it can lead to a damage of your phone.

author: Vovk_Z
author_rank: Super Contributor
timestamp: April 25, 2023, 12:13:18 pm
content: I'm not sure how big risk it is, but typically there is not much sence in connecting devices to it directly. (If you mean 'USB-powered devices'). That panel is very weak.USB-devices need steady regulated 5 VDC and at least 0.1...0.5 A current capability. But that solar panel delivers un-regulated voltage and only 0.01..0.1 Amperes (0.1 A into a short circuit but not into a load).

author: paulca
author_rank: Super Contributor
timestamp: April 25, 2023, 12:27:48 pm
content: I played with a similar one and couldn't even get it to charge an 18650, with and without a charge controller. Directly connected it produced virtually no power at 3.8V connected to the cell and after a full sunny day had increased the 18650 from 3.80V to 3.81V. With a controller the loses added up to exactly the gains from using one. A better controller might help you get a few more 100mW from it maybe.USB loads. No.A few LEDs maybe.Even the bigger 6" square 12V 1.5W panel was a struggle to get it to do anything. I tried an actually MPPT controller and a 3S lithium pack at 12.35V. Two days later, one of them sunny and the battery was at 12.13V. So the panel wasn't producing enough to run the charge controller.These micro panels need specialist charge controllers, small battery and occasional milli amp loads to be practical. Something like an emergency torch or an LCD weather station maybe. For a USB charger you will need to go for a specialist device (much money) or a much larger panel in the 10-15W range at least.

author: radiolistener
author_rank: Super Contributor
timestamp: April 25, 2023, 12:35:22 pm
content: yes, I have two 6" 2W solar panels and when we had mains outage for more than 3 days, and all my batteries were discharged, I was tried to use it to power FM radio, but two 18V 2W solar panels were unable to provide power even for FM radio receiver which requires 6V 120 mA.You can use it for trickle charge for some battery, but it requires a lot of days to get some significant charge level.

author: AndyBeez
author_rank: Frequent Contributor
timestamp: April 25, 2023, 02:11:01 pm
content: I have a 'folding' 8W solar panel designed for trickle-charging/maintaining a car battery, which successfully charges my phone; but notthatquickly. The output is 19V under full sun. However, it needs a 5V buck converter, like this one attached, to act as a regulator and protection circuit between the panel and the USB charge lead. This model of buck converter provides up to one amp. So it's not going to work fast but, it does charge after a few hours. Even under British sunshine.