Mregb 42,800mAh Portable Solar Powerbank

Edit (original review below): I found that it actually is possible to charge this using the solar power, but it requires unobstructed sunlight (outside, not just in a window), hours of sunlight, and at least a couple days of charging... to go up one bar. So it's not a total gimmick, but I certainly can't expect to get a full charge in one full day of direct sunlight. Given my often-low usage patterns, I can probably go from not powering my phone on solar at all to doing so maybe 25-30% of the time. Original review: The "solar" aspect feels like a gimmick. Don't expect to charge this power bank using the solar panel. It might(?) help keep it topped off, but you will not be going from zero to 100% by putting this in the sun for a few hours, or days, or weeks. I live in the US South where there is ample light, and I left this in the window for weeks with no apparent gain in battery power. The tiny trickle of power from the solar panel is just not enough to be meaningful. I expected much better results from the solar panel, so having it do almost nothing at all stood out (in a bad way). Other than that, the build quality seems decent and when fully charged (from a source other than the solar panel) it works well enough to charge other devices. The flashlight feature works, but it's extremely unlikely I will ever use that. Generally would not recommend, due to the over-promise and under-deliver nature of the solar panel.