Folding USB Solar Charger Teardown?

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eas
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Folding USB Solar Charger Teardown?

Has anyone seen any teardowns of any of the (~15-28W) folding, nylon ballistic cloth, USB solar chargers based on SunPower cells?

I’ve looked around and haven’t found any (maybe solar charger geeks aren’t comfortable with seam rippers and sewing machines?)

I’m curious about the construction and the cell configurations. Are they typically 6v nominal into a buck converter? 12v? 18v?

I just got a 21w version from “Balight” from Amazon, and I’ll probably take it apart sooner or later, but I wanted to get a better idea of what I’ll likely find.

If I’m likely to find a 12v or 18v device, I’m likely to take it apart sooner, because I’d like to add an unregulated output so I can experiment with other charge controllers.

Thanks in advance for any pointers or personal anecdotes.

Thanks!

eas
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Well, I decided to have a look at the insides of my 21w folding solar USB charger for myself.

It’s 2S-3P (or is it 3P-2S?). Each of the three panels encapsulates two SunPower cells in series, and then they are all wired up in parallel. I guess this should handle partial shading better than a 6S arrangement.

I can’t be sure that similar 21-28W panels with 5v USB outputs from Anker, Aukey, Blitzwolf, etc are wired the same way, but I think there is a good chance they are. There is a little more info, and some crummy photos, on the linked blog post, but the real meat of it is all right here.

netprince
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Sometimes you can tell by the number of cuts in the solar cells. Each cell produces 0.6v, so add up each division of the solar cell and you should get around 5.5-6v. So there are usually 10-12 cuts in the cell in order to get to 5v-6v. With that in mind you can usually tell the wiring…