Well, two years ago there weren't many solar panel retail manufacturers and commercial or custom was out of the wallet equation. First went out on a comparison, and was finding two retail manufacturer's did 12V as well as 5V, however amperage is king. More cells, more sunlight capture, more surface = more amperage.
Flexible Connections is one of them bottle necks. Regular Connections are not
an issue like in fixed applications. But fixed also have regulators in between so many cells. That's not practical for smaller panels unless you want to go lugging around a solar generator in which is several hundreds of pounds. Perhaps in 10 to 20 years solar collection will advance technologically like portable phones have.
At best, retail wise, the best efficiency is 20%. Think it was NASA's solar panels have 40% - but they have the resources and funds are not so limited like you and me. 15% efficiency is about the norm.
So again, more panel space gives more output and more amperage - at the cost of weight & storage.
Some companies use battery packs in between device and cell to give you the power. This is not a bad thing as when the sun goes down there's no more power - unless you have a charged battery pack. And there are times when the ambient temperature is so extreme charging a phone isn't an option. Turn the phone off, let it cool down, charge from a power off
state or charge a battery and then the phone in the evening.
Goal Zero uses a covering that reduces the efficiency rating but also makes the cells more rugged to various environmental effects. Bad part is their warranty stinketh. You can get a $100 panel and you will literally be sitting there wondering ... is it doing anything? Am sure there's works, yet side by side which panel will get that battery or phone charged faster? Gomadic
... I didn't take the plunge. If money wasn't an issue I would of gotten a Gomadic too. Even though their panels are bulkier, the fitted cases are worth it for protection and carrying the many
available adapters. There is no invasive coating neither. Their setup is very elite. Best thought-out product, past the soldering and silicone thing on the back of the panel. Though that should not be a problem, for some reason it stuck out in memory. Perhaps they've fixed that now??
This fella does the better review of the large 15W Gomadic panel https://youtu.be/BLbyErQGW9M
Me, would of gone for the SunStash MAX 15W Solar Charger
for the ability to recharge a laptop, which would be great if you lived out of your vehicle
There is a smaller version available too, a 10W, based on the same principle. SunTactics
grabbed me as they compared their products to others and showed the real-time results
Goal Zero started doing he same... but Goal Zero would pit their larger model against a competitor's smaller model.
One has to determine which is the best value for Size, Functionality, Weight, Quality, Durability, and most importantly (in my book) Warranty. Warranty, to me, shows how much confidence
the company has in their product(s). Then there is the thing of where was the unit constructed at, country wise. SunTactics is a USA made product. The other two are not. None of them are made in Canada.
You have to find your fit
. I was looking for THE BEST OF ALL WORLDS and Suntactics seals the deal with an encased product, real time and more fair comparisons, and durability tests. And when I thought there was a need for a replacement, BAM, it was there in a week!
Sure I talked with Dean Sala on the phone a few times first, but he gave me the option to send it in. Only wanted them to test the panel and send it back. Yet SunTactocs keeps on developing their products to perform better and recently acquired an advancement to get more juice out of their panels - for their size.
Got side tracked there for a bit. Many reviewers fail to understand basic fundamentals of solar panels. Unless the circuit is reset, any shadow will reduce the about of output a solar panel. Many devices that have built-in regulators, once dropped, will stay at that level of charging. Unless the circuit gets reset the charging stays low no matter what.
So if a reviewer is charging a phone, stands in front of the panel casting a shadow over it, the panel done lost 50% or more of it's output. The phone adjusts to that level of charge. When the reviewer moves out of the way the phone is still charging at that lower level due to the charging regulator built into the phone.
Unless the solar panel system has a device that resets the circuit the panel will only charge at that lower rate until someone unplugs the phone and plugs it back in.
Once another shadow crosses the panel, like a tree shadow, a bird, another spectator (Dude, you sure it's working, I can't see anything moving!), clouds, haze, solar eclipse, ect. the phone isn't going to bounce back up to maximum charge unless the circuit gets reset.
SunTactics has two ports on their dual-port models, (M) manual & (A) automatic. Automatic resets the circuit every so often to achieve maximum results. One problem with that is phones that have their screen staying on while charging will overheat. Found out the hard way. Lost a phone due to that and I thought it screwed up the panel too.
So allow the screen to turn off, turn off the GPS & WiFi too if you want the phone to recharge faster. or turn the phone off and charge even faster with it off. The more stuff running the slower the recharge and the greater the heat produced in the phone - especially it if has a case.
Goal Zero only recently put a circuit reset in their panels when SunTactics was outdoing them.
Most solar panels do not have a circuit reset, and all it takes is one shadow or atmospheric issue to lessen the recharge on your phone. Not a HUGE issue with larger panels, though it needed to be brought up.