Sunjack Solar Charger Review: Old vs New Hands-On

A few years ago, my interest was piqued when I came across a portable solar panel and charger from SunJack. I got the unit, used it extensively and own it to this day.

I recently had the opportunity to try out a new model from SunJack. It is a 25W portable solar panel with an improved design. Since I really like my old model, I was very excited to try this product! Let’s start with what the new model has to offer.

Technical data of the Sunjack solar charger

The following information is taken directly from the SunJack website.

Solar collector

The panels are made of monocrystalline material and provide 25 watts of power.


There are two 5V/2A USB ports on the rear panel.


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


When folded, it measures 31.8 cm x 20.3 cm x 3 cm (12.5″ x 8″ x 1.2″).

When unfolded, it measures 62.2 cm x 31.8 cm x 2.5 cm (24.5″ x 12.5″ x 1″).


This laptop weighs 3.0 to 1.4 pounds, including the weight of the batteries.

What’s included

  • 25W portable solar charger with two USB 2 Amp outputs
  • 2 Qualcomm 3.0 SunJack fast charge batteries
  • 2 SunJack quick charging cables
  • 2 SunJack carabiners

A practical exam

When I opened the box, I was surprised by the elegant design of the 25-watt device. It consists of three folding panels with a zippered mesh pocket on the back of the last panel.

USB ports, cables and batteries are stored in a mesh compartment that is accessible through two different zippers. In addition, this compartment contains two nylon straps for attaching two batteries.

Each panel is encased in a hard plastic frame with a smooth outer surface and a slightly rough inner surface. The exterior of the unit is completely black, while the edge of the interior panels is bright yellow.

Use of panels

There are two ways to use the panels. The first way is to unfold the panels and simply spread them out in the sun to charge the batteries.

The second method is to use the boards while driving. At each end of the frame, two holes are cut at the corners where the panel can be hung. This can be done with the rope or carabiners provided by SunJack.

This is an excellent option for hikers, trekkers or anyone who wants to keep a load on while moving from one place to another.

Backing plates

Once folded, the unit is quite rational, but the panels are not completely flat. There is a small gap where the frame overlaps.

Right now, the hole is quite large on one side, but that’s because the unit is new. With my hand, I was able to push this part down and compress the space to fit narrower places.

I would be careful, however, because wrinkles may form here over time. I am afraid this will weaken the material at this stage and cause problems. In any case, it is completely unreasonable at this stage and I am only thinking of my future use of the product.

At this point, I will do my best to pack the plates as they came to me and not crush them among other equipment. However, the folded plates fit easily in my bag and can even be slid under the car seat for easy storage.

Charge my phone

Okay, now it’s time to focus on the goal of this product: power. In this test, my phone’s battery was at 58% power.

I took out one of the batteries and put it on the coffee table. After pressing the power indicator button, I saw that three of the four blue lights came on.

Then I took the USB cable to charge the phone and plugged it into the battery. I let the stopwatch run and then connected the phone to the charging cable. Here are the results.

First payment 58%
Last payment 100%
Load time 108 min. 24 sec.
Distribution (approximate) 1 min 41 sec at 1% load

I decided not to do a timer test with the direct charging method. This is because the effectiveness of direct charging depends on several factors. First, the panels must be exposed to direct sunlight, which will not be a problem in order to obtain the most accurate results.

Second, the efficiency of solar panels also depends on their location. Some regions get more sun than others and I can’t change this parameter overnight. Therefore, direct pricing may be faster for some people than for others.

However, I connected the phone directly to the device and could see it charging evenly.

Load options

This portable device can charge four separate devices simultaneously. Two devices can be connected directly to the panel’s USB charging ports and one device can be connected to any battery.

It should be noted that devices connected to rechargeable batteries are charged the fastest, while devices connected directly to the panels are charged with different efficiency.

In addition, both batteries do not need to be connected to the panels to be charged. One battery can be removed and used to charge the unit, while the other remains connected to the unit for further charging.

Advantages and disadvantages


  • Robust construction
  • Renewable energy source
  • Easy to use
  • Two batteries for charging multiple devices
  • Direct Billing Option
  • Light
  • Can be suspended for a driving disqualification
  • If there is sunlight, the devices can be charged anywhere!


  • Panels do not lie flat when stacked

General Questions

Q: Are the panels charged only in direct sunlight?

A: No. The panels charge the battery even when mounted behind glass, such as a window. I have often done this at home or by placing the panel on the dashboard of my car. However, this reduces the efficiency of the panels and increases the charging time.

Q: Can panels be paid for on cloudy days?

A: Yes. The panels work well in adverse conditions with sufficient light. I was able to charge the batteries under a thick cloud cover and in low light conditions. But like the previous answer, it will increase the charging time.

From the old to the new Sunjack: a comparison.

At the beginning of this article, I mentioned that I own a SunJack unit from a few years ago. This unit still works and I continue to use it. But how does it compare to the new model?

Check out my review of the last 4 years of Sunny Jack.

Unfortunately, I think it would be a mistake to compare the two devices in terms of performance.

The old model I have is a 15 W unit, while the new model is a 25 W unit. In addition, the battery and panels of the 15 W unit are currently up to five years old, indicating a decrease in efficiency.

However, there are some differences between the two.

  • The old model has four panels, while the new model has three panels.
  • The old model has a soft case, while the new model has a hard case.
  • The old model has more attachment points for hanging panels.
  • The old model has Velcro to hold the folded panels in place.


I’m a big supporter of alternative energy sources, and while I have a love-hate relationship with technology, I understand that we are now taking it everywhere.

I think the 25W SunJack portable solar panel is an excellent product. It’s also great for a lot of people. I had a few power outages last year and it would have been a real headache to charge my phone if I didn’t have the SunJack charger.

But don’t forget hunters, fishermen, hikers, campers, boaters, cyclists and other adventurers. A portable solar charger is a great option for these folks to keep safety devices and phones charged when there is no outlet nearby.

I was incredibly happy with my old 15W portable solar panels because they turned out great. I think SunJack has hit a new eye with the new model and I look forward to using it as much.

Thanks for reading!

Have you ever used SunJack products? If so, tell us about it in the comments below and let us know!

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