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Test SLAR 5W 5V solar panel

May 07, 2021 — BarryK

Continuing the saga of testing these little photovoltaic solar panels, here is the previous test:

I came across one on Aliexpress that is sold with or without the USB 5V regulator, so I bought the one without:


It has a slightly thicker substrate than previous ones tested, so is more rigid. Weight is 90g. Brand name is "SLAR".

Today is Friday, May 7, 2021, and I setup the panel outside at 10.00am. Measured solar intensity at 810W/m2, ambient temperature 22 degC, blue sky, no clouds, slight breeze.

Got the measurements started at 10.15am, finished at 10.20am. Then again measured solar intensity, 820W/m2. The cell temperature, IR detector held about 50mm from surface, 46.5 degC.

Here is the plot:


The peak power point is about 4.8V @ 0.7A, which is 3.36W. Well well, this vendor is being honest, in contrast with other recent purchases. This is mid-morning on a winter day, sun low in the sky, so expect more power at midday, and in the summer.

That voltage-current curve has a very sharp knee, then rapid drop-off. This would indicate high quality cells.  

Tags: light