Voltaic Systems - Small Solar Panel 9W / 6V - Charcoal | Panel Made with High Performance Monocrystalline Cells | Waterproof, UV and Scratch-Resistant

I bought this to charge an outdoor weather station I built and it works perfectly for my needs. The project is driven by a Particle Argon which collects the data and sends it to me over WiFi. I am also utilizing an Adafruit bq24074 charging board, and a 3.7V LiPo 3700mAh battery (purchased here on Amazon). I did some extensive testing on the power draw of my setup, as well as putting the Argon to sleep to save power, and overall my whole system only draws around 8mA on average. This solar panel in direct sunlight gives me back upwards of 600mA. Even in the shade, during the day, it provides around 80-100mA. I need very little sunlight throughout the day to keep the batteries topped up. The build quality on it seems very durable, and the panel is very small and lightweight for what it delivers. I do wish the mount was included, or at least cheaper than another $10. I'd say this panel is well worth the price, but it stinks having to spend 25% more money just to get a metal bracket to mount it. That is not the fault of this panel though.

The solar panel seems to be well made and appears to be working as advertised. I used it to replace the solar panel on an outdoor led light that had died due to water infiltration into the solar panel. The panel keeps the batteries in the light charged even on overcast and rainy days which we get a lot of. Gave it 4stars because the area where the wires came out of the panel was not sealed as well as the rest of the panel. Overall satisfied with the panel. I also felt that the panel was a little over priced. I would recommend this panel at this point.

The 2nd image shows the product comes standard with a DC barrel jack, but it really has a mini-USB-c. This actually works better for my project but was unexpected for the original design plan. There should be more clarification somewhere on the product page.

Bonus connector. Apparently the maker listened to the review complaining about the 3.5 mm connector and mine came with a 3.5 mm to micro USB adapter already on it. The four corner screws on mine measure to be 4-40 screws. I thought they'd be metric, coming from China, but that's not what the caliper and thread gauge say, so they must be made for this market. The protrusion of the screws from the back of the unit is 0.18" on mine, so almost 3/16". This is fine for sheet metal or corner bracket mounting. If a taller standout is needed you can buy 4-40 circuit board standouts of the length you want. The peak output voltage I saw here in the city in late March, was 7.58 with no load. It will be higher at the end of June, when the summer solstice occurs. Since this type of solar panel usually puts out its maximum power when loaded down to around 80% of their unloaded peak output voltage, this means the output will be pretty close to 6V or maybe a little over that when power delivery is at its peak in late June. This is about right for most lead-acid batteries, and it gives some headroom for charging cell phones.

won't charge a LG Stylo 3

I bought this to keep my Voltaic Systems battery bank charged up while on the go, which in turn keeps my phone and tablet charged up. I does a good job of that. The only thing that would make it better is if worked indoors also. (At least it doesn't work inside my house with artificial lights.)

Excellent when paired with a Voltaic always-on battery. I put a Voltaic battery in a tupperware, drilled a hole for the panel cord, and it charges that battery daily. This all to power a GoTenna Mesh device in relay mode. So it's a compact communications relay that is powered by the sun. It's been going for months now. I have absolutely no complaints.

4.5 stars! This small unit fits on the back of my camelbak when I do distance cycling, keeps my phone charged nicely, weighs next to nothing and seems unbreakable and weatherproof. Will it charge your mega-device in a short time? No, but it will keep your phone topped up nicely. Here's the half-star rub - it uses a rare-ish 3.5x1.1mm plug as output and you have to hunt up an adapter (in my case a female 1.1 mm to micro USB male for my android phone). This adds a whole $1.50 or so (from Ebay - Amazon doesn't seem to have them). While I realize that the cell is as much for hobbyists as the USB crowed, one would think that a standard USB socket would be included (or offered at a reasonable price - their version that I went with at first out of desperation was nearly $12 shipped). All of that aside, I'd do it all over again - just incredibly handy.