The world's most in-depth and scientific reviews of outdoor gear

PowerGreen 21W Review

Well designed, comes in multiple colors, and is durable - but also bulky.
PowerGreen 21W
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Price:  $40 List | $39.99 at Amazon
Pros:  Large storage pocket, comes in multiple colors, durable
Cons:  Heavy, bulky
Manufacturer:   PowerGreen
By Jane Jackson ⋅ Senior Review Editor  ⋅  Nov 11, 2019
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68
OVERALL
SCORE


RANKED
#4 of 14
  • Charging Speed - 30% 7
  • Charge Interruption Recovery - 20% 7
  • Multiple Device Charging Speed - 20% 6
  • Weight & Portability - 20% 7
  • Durability - 10% 7

Our Verdict

Efficient and stylish, the PowerGreen's main attraction is its user-friendly design. It comes in multiple different color options and has easy to follow instructions written on the panel itself. This makes it approachable and very easy to use. It also has a large storage pocket and no extra material, which contributes to its smart design. The user-friendly design is a good option for car camping or "van life" where you are mobile and off the grid, but not carrying all your worldly possessions on your back. Since you can pick out your color choice and hang the panel in your window using the reinforced grommets, it does better in the back of your car rather than taken with you on human-powered adventures.


Compare to Similar Products

 
PowerGreen 21W
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PowerGreen 21W
Awards  Editors' Choice Award Best Buy Award   
Price $39.99 at Amazon$59.99 at Amazon$39.99 at Amazon$29.99 at Amazon$114.99 at Amazon
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Pros Large storage pocket, comes in multiple colors, durableInexpensive, efficient, user-friendly, excels in partly cloudy conditionsInexpensive, lightweight, portable, charges quicklyRelatively lightweight for panel type, inexpensive, charges devices efficientlyPowerful, works well in partial sun, cheaper than other laptop compatible options
Cons Heavy, bulkyBulky, heaviest weightLow output power, cannot charge multiple devices at onceIneffective if relying only on solar for power, less durable than other battery packsBulky, heavy, hard to set up, complicated adapters for laptop charge
Bottom Line Well designed, comes in multiple colors, and is durable - but also bulky.We were impressed by its ability to charge our gadgets quickly and reliably; its reasonable price is the cherry on top.This panel impressed us with its fast charging speeds and its lightweight, portable design.An efficient, compact battery pack with a 2W solar charger on it; a top performer.The X-Dragon 40W is the largest panel we tested and works relatively well for charging a laptop, though it is cumbersome and heavy.
Rating Categories PowerGreen 21W BigBlue 28W ECEEN 13W Renogy 15,000mAh X-Dragon 40W
Charging Speed (30%)
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9
Charge Interruption Recovery (20%)
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6
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8
Multiple Device Charging Speed (20%)
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6
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7
Weight & Portability (20%)
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Specs PowerGreen 21W BigBlue 28W ECEEN 13W Renogy 15,000mAh X-Dragon 40W
Panel Size (watts) 21W 28W 13W 2W 40W
Weight (measured) 20.3 oz 23.5 oz 12 oz 9.5 oz 37 oz
# of USB outlets 2 2 2 2 1
Max USB Output Current (amps per port) 2 amp 2 amp 2 amp 2 amps 2.8 amps
Battery kit? No No No Yes No
Size folded 11.4" x 6.8" x 1.3" 11.1" x 6.3" x 1.3" 11.4" x 6.1" x 0.6" 6.3" x 3.1" x 0.7" 10.43" x 6.3" x 2.76"
Battery? No No No Yes No
Charge tablet? Yes Yes Yes No Yes
Charge laptop? No Yes No Npo Yes
Panel Type Mono-crystalline PET Polymer Mono-crystalline Mono-crystalline PET-Polymer
Size opened 27.6" x 11.4" x 0.2" 33.1" x 11.1" x 0.2" 11.4" x 14.3 x .15" 6.3" x 3.1" 0.7" 35.2" x 18.1" x 0.04"
Battery input (Volts / Amps) n/a n/a n/a 5V 2A n/a
Charge capacity (mAh) n/a n/a n/a 15,000mAh n/a
Charge iPhone/smartphone Yes Yes Yes Yes Yes
Direct USB Plug? Yes Yes Yes Yes Yes
Daisy Chain? No No No No No
12-Volt connection No No No No Yes
Warranty 1 year 2 years 30 day return 1 year 2 year

Our Analysis and Test Results

The biggest draw of the PowerGreen 21W panel is its design. From the materials used for its construction, mainly the PET Polymer faced panels (which are incredibly durable) to the thoughtful, roomy storage pocket, the 21W is easy to use. On the downside, the PowerGreen is the heaviest set-up in our testing fleet.

Performance Comparison


From left to right  the X-Dragon 20W  the PowerGreen 21W  and the Anker 21W.
From left to right, the X-Dragon 20W, the PowerGreen 21W, and the Anker 21W.

Charge Interruption Recovery


The 21W by PowerGreen did not quite stand up to the other large panels in our fleet. Initially, the PowerGreen charged up our battery to 3%, just as the other larger capacity panels did. But, once we had interrupted the steady flow of sunlight to the solar cells, the panel had trouble reconnecting to the battery that was plugged into it. The battery wasn't charging at all after the panel had been in the shade, and we had to unplug and re-plug it back in to establish a sound connection. Some panels have technologies built in that will read the input and re-adjust accordingly, and that makes their recovery faster.

Charging Speed


Charging speed was another category where the PowerGreen narrowly missed the performance level of the other two large capacity panels. After one hour of charging our 1byone 6,000 mAh external battery pack, the PowerGreen had only charged the battery to 13%. This is a fairly large difference, especially when we checked again after three hours; the PowerGreen was still almost 10% behind the other large-capacity panels we tested. This lag played a significant role in the PowerGreen's overall score since keeping a phone or battery charged is the main job of these devices.

The PowerGreen is the largest  and heaviest of the panels we tested. But  it was one of the top scorers that could charge multiple devices.
The PowerGreen is the largest, and heaviest of the panels we tested. But, it was one of the top scorers that could charge multiple devices.

Multiple Device Charging Speed


When we plugged in two of our test batteries to the 21W, the panel slowed down considerably in delivering power to both batteries. This is normal since suddenly, each USB port is pulling half the total wattage of the panel, making it seem like they are each essentially plugged into a 7-10W panel. This slows down the charging a great deal, but some models recover better than others. The 21W was able to maintain a charge to both batteries but failed to actually increase the charge on either. Some panels could not consistently supply power to the batteries; this caused the battery to continually disconnect and reconnect, rather than receive a steady flow of power.

Durability


The 21W panel's greatest attributes are its design. The panel is burly and can withstand wind, light rain, and sand (of course, as with anything, to an extent!). If you like hanging your panels up to receive sunlight, the PowerGreen has sturdy, re-enforced grommets. The durable canvas and PET Polymer coating on the cells makes the PowerGreen especially durable, and we didn't run into any issues with the pocket wearing or the fabric wearing out along the fold lines.

Like the Goal Zero Nomad 7  the PowerGreen has a mesh pocket  which is nice to be able to see what electronics are inside  but is also less durable than a canvas pocket.
Like the Goal Zero Nomad 7, the PowerGreen has a mesh pocket, which is nice to be able to see what electronics are inside, but is also less durable than a canvas pocket.

Weight & Portability


Generally speaking, the larger the wattage, the heavier the panel. With this in mind, it's not surprising that 21W is one of the heaviest in our fleet. Many of the foldable panels we tested end up being about the same size as the PowerGreen when folded, but the PowerGreen weighs in higher on the scale.

The re-enforced grommets allow the PowerGreen to be hung up anywhere  easily  without having to fiddle around with carabiners.
The re-enforced grommets allow the PowerGreen to be hung up anywhere, easily, without having to fiddle around with carabiners.

Value


This panel is a great budget option. For the price, it has a careful design and high powered solar cells. That said, spending just a hair more will get you a more efficient panel that will charge your devices faster and more effectively.

Conclusion


The PowerGreen 21W has lots of bells and whistles that make an aesthetically appealing purchase; however, after further research, we didn't find it was all it cracked up to be. Since the PowerGreen boasts 21W, it's somewhat efficient, but still struggled to charge two batteries effectively. It also lagged in the race to charge our battery pack. For these reasons, we found that there are better options if you're looking for a panel of this capacity.


Jane Jackson