My first solar panel had around 7W (around year 2014/2015)
Today the cells are all high output SunPower I don't know if they exist with such low wattage today, maybe something minimal in size.
My favorite brand is X-Dragon (available 14W and 21W)
It has a good controller and restarts itself in case a cloud passes by.
There is a well-designed zippered mesh pocket where the two USB sockets are, you can walk around and leave a device in your pocket to charge without running the risk of it falling out and getting lost.
I also have other brands of solar panels but this X-Dragon is the top of the ones I have.
Yes on the beauty of using solar photovoltaics for flashlight batteries, and very good feeling to charge the ebike with the sun. What Stefano said about having to reset when clouds happen, that is important.
Consider getting a larger solar panel that can be in position all the time to receive power. It can still be portable (or not). At a later stage, get a substantial means of electrical storage (with a charge controller), whether lead acid or lithium based. Now you can run much more than a flashlight; stereo, TV, indoor lighting, fan, something else you have. You never know when it might come in very handy under abnormal circumstances.
This Goal Zero is definitely portable as it is requested in the subject of the post.
But I see it's very expensive, it only has one charging port (max 1A) and no pouch to hold your devices.
If you are on the go you will need to keep the devices in your backpack and connect them with a long cable.
With that amount (59 dollars) perhaps two panels could be bought.
I also love small panels, unfortunately I find today that X-Dragon has discontinued the 14W panel (two cells) and produces the 21W three-cell panel as the base panel.
The smallest panel I own is an old AllPowers 7W bought as I wrote earlier in 2014/2015 on Ebay directly from the manufacturer.
I don't know if there is something equally small on the market, the panels of my old AP are of the old technology.
With the current SunPower cells you can have 7W with half the size of my old AP you see in the picture.
But except this Goal Zero does it seem to me that manufacturers are not very interested in small panels?
I see a "race for watts" rather than size and practicality..
The way I see it is Goal Zero realized that black nylon (which made up much of their earlier panels with pockets) degrades quickly in the sun. Their newer designed panels don’t have pockets, but they should last longer. They have attachment points you so can clip them to a backpack. Run a cable from the USB port on the panel to you device in a backpack pocket and you have power on the go. I don’t see a problem. I’m sure there are a hundred cheaper panels. When I go out in the backcountry and depend on something for survival, I don’t care how cheap something is. It better work or I could die. If you’re using a solar panel for charging a flashlight during a long term blackout or charging a cell phone to call for help, don’t get the cheapest piece of junk solar panel you can find. Get something dependable.
Looking for a solar-charged light for inside a shed. All the cheap stuff I see gets bad reviews for various reasons. What about a good panel charging a small Lion battery pack, with a long USB cord to the light... The light won't be used for more than 15 minutes at a time.