Aukey 20 Watt Portable Solar Charger

“…Shading obstructions can be from “soft” or “hard” sources. If a tree branch, roof vent, chimney or other item is shading from a distance, the shadow is diffuse or dispersed. These soft sources significantly reduce the amount of light reaching a solar panel’s cells. Hard sources are defined as those that stop light from reaching solar cells, such as a blanket, tree branch, bird dropping sitting directly on top of the glass. If even one full cell is hard shaded, the voltage of that module will drop to half of its un-shaded value in order to protect itself. If enough cells are hard shaded, the module will not convert any energy and will, in fact, become a tiny drain of energy on the entire system.

Partial shading of even one cell on a 36-cell solar panel, will reduce its power output. Because all cells are connected in a series string, the weakest cell will bring the others down to its reduced power level. Therefore, whether 1/2 of one cell is shaded, or 1/2 a row of cells is shaded, (as shown above), the power decrease will be the same and proportional to the percentage of area shaded, in this case 50%.

When a full cell is shaded, it can consume energy produced by the remainder of the cells, and trigger the solar panel to protect itself. The solar panel will route the power around that series string. If even one full cell in a series string is shaded, as seen on the right, it will likely cause the module to reduce its power level to 1/2 of its full available value. If a row of cells at the bottom of a solar panel is fully shaded, as seen in Figure 7, the power output may drop to zero. The best way to avoid a drop in output power is to avoid shading whenever possible.”

It’s not a matter of believing what I want. It’s a matter of facts. The solar panels are rated according to a well established testing standard. Further, one of the review links you posted that I clicked on https://www.youtube.com/watch?v=kVInRQJMtzU showed the panel made it’s rated power. You’re really talking about the total power output through the USB ports, not the solar panel’s output into the USB power circuitry. They’re not the same thing. It’s not that the solar panels are overrated, it’s that the USB power circuitry connected to them is crap. As you’ve shown, laundering solar energy through USB charging ports is not an efficient use of the solar energy.

Is it misleading to call a 20W solar array connected to a USB charging circuit that can only deliver ~10W from the USB output a 20W solar charger? Probably, but it’s no different than power banks being labeled based on the mAh capacity of the cells in them, not the the mAh they can output at 5V (which would account for the voltage difference and the efficiency of the output circuitry).

I love these little 20w (really 10-12w) foldable solar panels. It is really interesting how much has to be done to take power from solar panels and make it work in a usable way.

For example apple devices wont ramp up current draw again after a cloud goes by. Some newer foldable panels will automatically detect the cloud is gone and reset the usb port. Some detect there is a cloud blocking the sun and just shut off the port.

Wish there were more (reliable) reviews on these…

+1

We do agree that efficiency is the number one problem in many designs including solar panels, the needed USB circuitry, and the device being powered.

The bottom line is that testing in real use is the best and maybe only way to test between what a product is advertised at and what it does in actual operation.

Amen. I hope this forum really does get into assessing these little solar panels and battery packs as standalone, hands-off-reliable ways to collect and use power.

For solar collecting, budget light IN is as important as budget light OUT for flashlights.

We’re putting together a great compilation of ways to do it wrong as well as right. Both are important to know.

As J. Baldwin of the old Whole Earth Catalog put it: “You don’t know how to use a tool until you know six ways to break it.”

From experience here, we can add: “You don’t know how to build a tool until you know six ways to fake it.”

+1

I retired as an auto mechanic and it took me years to learn the many things a hand tool could do outside of its first purpose. :slight_smile:

I had forgotten I had already translated my Blitzwolf solar charger review.
You can find it here if you’d like to read it.

It’s very inefficient to use such panels for everyday, it’s just a nice toy.
Especially if you use a Powerbank and solar panel the return of investments is in no sight. Also the power losses are exorbitant. The best thing is to charge it through mains. Also for camping it’s not of any use if you have a car nearby which can endlessly charge a Powerbank and all other USB devices.

I like to play around and so I have plenty of powerbanks and solar panels. The anker/Blitzwolf one is a good value for the price but there is no good way to stand it up(that’s why I like the one from OP)
I always stand one third up and let the other two lay flat, that is very inefficient(30 degree towards sun doubles the possible amount of sun)

It’s totally possible with such an panel and a Powerbank to run your phone/tablet in summer. I put the panel on the balcony and let it charge through the day. In summer 5Ah is possible so even if you are to lazy or there are some cloudy days it works and my 10Ah power bank is always full.
BUT it only works in such a good way if the sun is directly shining for at least some hours. Now in October and in Germany it’s not possible to charge my phone and tablet completely because I get 0.2A max(it’s quite good for a solar panel without direct sun) in indirect sunlight of a cloudy day.

Maybe I will diy a stand with a bit of cardboard and ductape once….

I’m interested in this because I live a few blocks from a rather famous earthquake fault that’s a few decades overdue.

I want to leave a small solar panel in a sunny south window with a USB ‘octopus’ feeding four little power banks, and each of those feeding an item — cell phone, radio, ham radio — that I may want urgently when everything goes dark and things have just quit falling off shelves and the air is full of dust and I can imagine there may be a faint smell of gas in the air.

Ya know, the sort of time you really don’t want to just flip a light switch or plug something into the mains.

I keep hoping some of those here brilliant with small electronics can come up with a little tiny “toy” single-axis sun tracker, that would move one of these small panels through the arc the sun follows.
Adjust that manually every three months for seasonal changes.

I am living in a similar situation with the addition of fire danger.

My use for solar is not for running 120/220 volt household. It is used to keep powered up a group of highly efficient (90%) power-banks.

Oh, yeah, there’s that.

The short form advice here is: “plan for it to happen, it will”

In Europe, the equivalent would probably be tanks rolling across Poland — something like that, something that happens about as often and with comparable results.

I recently went overboard and purchased several of these fold-up type solar panels. I am considering doing a very small review on each of them, but I’m not sure what would be of most interest to people? Any suggestions?

> most interest

Which voltage regulators work with them so they will keep a storage battery charged
(including intervals of shade and overnight (do they return to charging after an interruption))
while you attach and charge and remove your mobile (phone, camera, flashlight) chargers/batteries.

Look at the common run of reviews
https://www.google.com/search?q=portable+folding+solar+panel+comparison+test+table
supply the info they mostly ignore

Use the search function provided on the site here or else put
site:budgetlightforum.com
into the Google search string to find specifically the other reviews here

I can test a couple phones and a couple battery banks as interruptions occur… I understand apple products can be picky about intervals of shade and sun, so that could be interesting.

Can you be a little more clear about the voltage regulator suggestion? I dont have much in the way of testing equipment, but I do have a cheap usb charge monitor.

One thing I found interesting is what happens with extremely gradual power ramp up, like what you get when the sun is rising. Some electronics just freeze up.

https://www.google.com/search?q=solar+panel+voltage+regulator+battery+charger

My test on this panel:

For what it is worth, I noticed this charger on sale on amazon the last couple of days.

This site does a good job of tracking Amazon’s wild price swings and gives some price history.
This one’s not in stock right now (actually nothing from Aukey seems to be, but that can change fast or your results may differ)

Note the very brief low price spike.

Narrow it down to something Amazon says they have in stock, or follow the 3rd party price links — this finds far more than that:
http://camelcamelcamel.com/search?sq=aukey+solar+charger

Reviving an old thread. Does anyone have any advice on decent current solar chargers? I’m looking to stock one simply for an emergency. Would like to charge both Ni-Cad and Lithium’s. I already have most major plug in mains chargers. Opus 3100, Li-500, Xtar something etc to pair with it.