back to testing solar panels and accessories

simulating sunlight:




You can't just use any indoor lighting source for testing solar panels. The light "color" (frequency) meeds
to be right, and the bulb needs to be producing a lot of power. This means LED bulbs are completely out of
the question, it has to be an incandescent bulb. But creating a calibrated light source is probably not going
to be realistic, but at at least panels (especially small ones) can be tested in more controlled conditions.
Plus now I don't have to wait for a sunny day to see if a panel is at least functional.

I ran across a solar demo unit and it used a pair of "A21 E26" 200w bulbs to excite its demonstration panel.
These do seem to work well, although they're power hungry and get hot pretty fast. But they work anytime,
day or night. I see there's also a 300w version of this light that would probably work better, but this one
seems to be doing the job here for me.

Don't forget, just because it's a 200w bulb doesn't mean it's generating 200w of light. Incandescent bulbs
are incredibly inefficient. These bulbs are designed different than general purpose bulbs though so they do
emit more light. One source I found says 3,200 lumens, which is much more than the typical 1,800-2,600
lumens of a general purpose incandescent bulb. Unfortunately, every calculator I found gave me the watts
that the bulb drew from power, so they all said about 200.

However, incandescent "efficacy" is around 12-18% though and I think that can be used with power, so
18% of 200w is 36w, and I suspect that is the "light power" here. So if I wanted to make a light box for
testing 100w panels, I'd need to light it with three of these bulbs. But it should be fine for testing up to
around 20w panels at full power - larger panels would still operate but at reduced output which is also fine.



200w A21 E26 2700K light bulb ($5 at Home Depot)

2025.11.28 panel and lipo charge board testing (in test sessions)


200w A21 E26 2700K:



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