Let’s Build 5V Solar Charger Part 2

Let’s Build 5V Solar Charger Part 2

Last week, I assembled step-up boost converter kit and put 6V solar panel to power up the chip. I did a final assembly inside a metal casing and taped the solar panel around the case to make the kit tidy as shown in the photo below.





This week, I measured the output of the solar charger. I measured the open circuit voltage and short circuit current to calculate the power output. The voltage was measured at around 6V and current was measured at around 0.03Amp. This translates to around 200mW of energy. This is 1/5 of what the solar panel was advertised at. The product page advertised at 1W of output. I expected that the tiny circuit wouldn’t able to charge a power hungry smartphone. However, this might be sufficient enough to charge a small LED light for my bike. Considering that normal USB port’s maximum current output is 500mW, the solar panel’s output is decent. 


For curiosity, I calculated how much energy I could save using the solar charger. I made a hypothetical usage condition. Let's say I park my bike outside 5 hours a day for 5 days a week for 20 weeks of the year. That is 0.200W* 5hrs * 5days* 20weeks =  100Wh of energy. 2016's average cost of electricity was 12 cents/ kWh. So I would save a couple of cents a year. So the energy saving is negligible. However, while the energy saving from a hobbyist size miniature solar panel is negligible, this is a proof-of-concept that shows it is possible to use renewable solar energy to create electricity to use for purposes intended for its power output.


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