When you're shopping for big commercial panels and installations for your house, the numbers are usually
fairly accurate, but when you step into the "hobby" market on Amazon and eBay, scams are everywhere!
You need to educate yourself on what's reasonable so you have the right expectations for power and cost.
There's so much solar available to buy right now that they're all at around the same performance and price.
Anything that looks too good to be true is a fake. The more you hunt for a good deal, the more fakes you'll
end up with in your bookmarks list. Buy from a seller that has lots of units sold and good feedback.
For ultra-portable solar I go with the semi-flexible panels. Most are using the same standard size cell
(5" square) so you'll see them a lot. They usually have a row of 4 by 8 or 9 cells, (32 or 36 cells total)
and are about 21" x 46". They'll be rated 100 watts, but that's not what you'll get unless you live in a lab
under a giant lamp. That number is for comparison purposes only, and a 100w panel will deliver about 75 watts
of power under good conditions, which is what you should budget for. Panels like that cost around $100, but
can be had for around $75 if you buy a set of 4 or 8 of them. Anything over $125 is a ripoff. Only buy
"monocrystalline", not "polycrystalline".
The ratings on many panels for sale are downright hilarious. I've seen panels with only 2x3 cells (6 total)
claiming 100 watts, and I've seen the regular 4x8 and 4x9 panels rated up to 300 watts. Not gonna happen.
Six cell panels are good for around 18 watts, which is still useful for say, charging a phone. Those often
come with a USB port on them, so I'll give them a pass, as long as they're under $20. Anything with less than
six cells (or the equivalent area of cells) isn't worth your time, you won't get a full charge if you let it
sit in the sun all afternoon. I see larger cells are popping up now, where a 3x7 panel is just as large, and
might be honestly rated 100w as well, so pay attention to the panel size, or you'll get a nasty surprise.
Strangely, lately I've seen aluminum-framed, glass-covered rigid panels for sale for LESS than the flexible
ones, which seems backward, as there's more material there, but maybe there's just a "tax" on flexibility?
So if you're just looking to experiment, or don't need a lot of portable power, maybe a rigid panel is a
better idea for you.
I've had good luck with Dokio brand panels. They're 1180 x 540 mm / 1.1kg. (46.5 x 21.25 in, 2.5 lbs), have
grommet holes for mounting / tying down, are flexible and waterproof. (they use MC4 connectors)
