Sunjack Solar Charger Review: Old vs New Hands-On

This post contains affiliate links. If you click on a link and make a purchase, we may earn a commission at no additional cost to you.

By Bryan Lynch •  8 min read

Several years ago, my interest was piqued when I came across a portable solar panel and charger unit made by SunJack. I received the unit, used the heck out of it, and still own it to this day. 

More recently I had the opportunity to try out a newer model by SunJack. It is a 25W portable solar panel unit with a few upgrades in the design. Considering how much I love my old model I was very excited to try this product out! Let’s get right into it by starting with what the new model has to offer.  

Sunjack Solar Charger Technical Specifications

The following information was obtained directly from the SunJack website. 

Solar Panel 

The panels are made from mono-crystalline and provide 25W of power.


On the back of the panel are two 5V/2A USB ports.


There are two 10,000mAh lithium-polymer batteries with a USB-C and Quick Charge 3.0.


When folded up the unit measures in at 12.5” x 8” x 1.2” (31.8cm x 20.3cm x 3cm)

When the unit is unfolded it measure in at 24.5” x 12.5” x 1” (62.2cm x 31.8cm x 2.5cm) 


This portable unit weighs in at 3.0 lbs/1.4 kg which includes the weight of the batteries. 

What’s Included 

Hands On Review

After opening the box, I was surprised by the sleek design of the 25W unit. It is made up of three folding panels with a mesh zippered pocket located on the back of the last panel. 

The USB ports, cables, and batteries are all housed within the mesh pocket that can be accessed by two different zippers. Also, in this compartment are two nylon straps for keeping the two batteries secured. 

Each panel is encased in a hard plastic frame with the exterior being smooth and the interior being somewhat rough. The outside of the unit is all black while the perimeter of the inside panels is bright yellow. 

Using the Panels 

There are two ways that the panels can be used. The first way is to unfold the panels and simply lay them out in the sunlight to charge the batteries. 

The second way is to use the panels while on the move. On the corners of the frame at each end, there are two holes cut out from which the panel can be hung. This can be done with cordage or by using the carabiners provided by SunJack. 

This is a great option for hikers, campers, or anyone who wants to keep charging while moving from place to place. 

Carrying the Panels 

When the unit is folded up it is rather streamlined but the panels do not lay completely flat. Where the frame overlaps there is a bit of a gap.

Right now, the gap is quite large on one side but that is because the unit is new. With my hand, I was able to press this section down and compress the gap, which would allow it to fit into tighter spaces. 

But I would be cautious doing this as over time a crease may develop here. I fear that this could weaken the material at that point and cause problems. However, this is completely unfounded at the moment and is just me thinking through my future use of the product. 

For the time being, I will do my best to pack the panels as they came to me and avoid squishing them between other gear. Having said that, the folded panels easily fit inside my bag and can even slid under a car seat for convenient storage.   

Charging My Phone 

Okay, now it is time for what this product is all about, power. At the time of this test, my phone battery was at 58% power. 

I removed one of the battery backs from the unit and laid it on my coffee table. After pressing the power indicator button, I saw that three out of the four blue lights were lit up.

I then took the USB charging cable for my phone and hooked it up to the battery. I started a stopwatch and then hooked my phone to the charging cable. Below are the results.

Beginning Charge58%
Final Charge100%
Time to Charge108min 24 seconds
Break Down (approximately)1 min 41 secs per 1% charge

I chose not to do a timed test with the direct charging method. This is because the efficiency of direct charging is going to depend on a few things. First, the panels must be in direct sunlight, which would not be a problem, to obtain the most accurate results. 

Secondly, the performance of solar panels is also dependent on location. Some regions receive more sunlight than others and that is a parameter I cannot easily change. So, direct charging may be faster for some people over others. 

However, I did directly hook my phone up to the unit and watched it steadily charge.   

Charging Options

This portable unit has the ability to charge four separate devices at once. Two devices can be plugged directly into the USB charging ports on the panels and one device can be plugged into each battery, respectively.

It should be noted that the devices plugged into the battery packs are going to charge the fastest while the devices plugged directly into the panels will charge with varying efficiency.

Additionally, both batteries do not have to be plugged into the panels to charge. One battery can be removed and used to charge a device while the other battery remains hooked up to the unit to continue to charge.

Pros and Cons 



Common Questions

Q: Do the panels only charge in direct sunlight?

A: No. The panels will charge the battery pack even if they are set up behind glass such as a window. I have done this a lot in my home or by laying the panel out on the dashboard of my vehicle. However, doing so will reduce the efficiency of the panels and increase the amount of charging time. 

Q: Can the panels be charged on cloudy days?

A: Yes. The panels still work even in unfavorable conditions if there is enough light available. I have been able to charge the batteries under a thick blanket of clouds as well as some lowlight conditions. But just like the previous answer, this will increase the amount of charging time.  

From Old to New Sunjack: Comparison

I stated at the beginning of the article that I had a SunJack unit from several years ago. That unit is still working strong and I continue to use it. But how does it compare to the new model?

Make sure to check out my 4-year review of the Sunjack.

Unfortunately, I think it would be a mistake to compare the two units where power is concerned.

The older model that I have is a 15W unit whereas the new model is a 25W unit. Plus, the battery pack and panels in the 15W unit are upwards of five years old at this point, so decreased efficiency is to be expected.

However, there are some differences between them. 


I am a big fan of alternative energy sources and while I have a love-hate relationship with technology, I understand that we now take it everywhere. 

I think the 25W portable solar panel unit by SunJack is a great product. It is also great for pretty much anyone to own. I experienced several power outages this last year and keeping my phone charged would have been a real problem if I did not have a SunJack charger. 

But do not forget hunters, fisherman, hikers, campers, boaters, bicyclists, and other outdoor adventurers. A portable solar charging unit is a wonderful option for these people to keep safety devices and phones charged when a wall outlet is not around.  

I have been incredibly happy with my older 15W portable solar panels as they have performed admirably. With the new model, I think SunJack hit another one out of the park and I look forward to using it just as much.

Thanks for reading! 

Have you ever used any SunJack products? If so, sound off in the comment section below and lets us know!

Bryan Lynch

Bryan grew up in the Midwest and spent every waking moment outdoors. Learning how to hunt, fish, read the land, and be self-reliant was part of everyday life. Eventually, he combined his passions for the outdoors, emergency preparedness, and writing. His goal was to spread positive information about this field. In 2019, Bryan authored the book Swiss Army Knife Camping and Outdoor Survival Guide. His second book, Paracord Projects For Camping and Outdoor Survival, is scheduled to be released on March 2, 2021.