Powerful enough to be practical, and small enough to be packable, this solar charger offers a lot of features in a tiny package.
I've used and reviewed a number of solar chargers over the last couple of years, and by and large, most of the currently available units are not exactly the most portable devices, even the folding ones. Sure, you can fit a folding solar charger, such as the Sunjack 14W (which I really like), into a bag or backpack and they only take up about as much space as a book when folded, but they require a bit larger of a space to actually operate them when fully unfolded.
Larger capacity solar chargers such as those are great for when you need more recharging potential for your larger devices, but for many people who are looking for an everyday carry (EDC) solar option that's quick enough to be practical for charging smartphones and other mobile devices, yet small and light enough to fit in a pocket or purse, they really don't fit the bill.
And one of the things I've learned about portable solar devices, both from my own experiences as well as feedback from other users of mobile solar chargers is that if the devices aren't simple to use and easy to carry, they don't get used very often, and are more likely to be sitting in a drawer instead of out in the sun generating electricity. Not only is that a waste of money and resources, but it's also likely to lead to some serious frustration, because when your battery is dead, the first thought to come to mind is usually, "I wish I had packed that solar charger," followed by "Where is the closest public outlet that I can plug my device into?"
The good news is that there is a serious solar charging solution that is not only powerful enough to efficiently charge most smartphones and other mobile devices, includes a built-in battery bank for storing a charge, and is small and light enough to go just about anywhere you do.
Solpro Helios Smart review:
I previously covered the Solpro Helios Smart charger when it was first released, and made the prediction that "this new gadget could be the everyday carry solar charger we've been waiting for," based just on the specs alone. That may have been overreaching a bit, but now that I've had the opportunity to get hands-on with the device and put the Helios to the test, I can honestly say that this little solar charger is indeed the everyday carry solar charger we've been waiting for.
Measuring just a bit bigger than a smartphone when folded up (5.1" x 3.15" x 0.79" / 130 x 78.5 x 20mm), and weighing in at just over half a pound (0.63lb / 286g), the Solpro Helios Smart unfolds to reveal three thin high performance solar panels rated at a total of 4.86W, measuring 5.1" x 11.0" x 0.63" (130 x 260.5 x 16mm). When folded up, the tri-fold panels (which are wrapped in a "leatherette" cover) are held in place with small magnets, and two holes in the case provide an easy way to clip or hang the unfolded unit while charging.
The bulk of the size of the device comes from the built-in battery bank, which is rated at 5000mAh and takes about 4.5 hours of full sun to fully charge (it can also be recharged via the grid using the micro-USB port). Depending on the model of the smartphone or other device being charged, the battery bank is capable of delivering three full charges, or devices can be charged directly in about 90 minutes.
Device charging is done through one of two USB ports on the end of the device, with one putting out 1A (for smartphones and "wearables") and the other producing 2.1A (for larger devices such as tablets). The dual ports allow it be used to charge two devices at the same time, although my experience with the Helios seemed to indicate that it's still better to charge the devices one at a time. The Helios Smart includes rubber plugs for the two USB ports, as well as for the micro-USB port, which will help keep dust and dreck from gumming up the ports. The plugs aren't tethered, though, so they are easier to lose, but it's a nice touch.
Here's my quick video review of the unit:
In my experience with the Solpro Helios Smart, the solar charger does produce enough electricity to fully charge a smartphone (an iPhone 4S, in my case) in about 90 minutes, and it does fully charge the battery bank in about 5 hours. Of course, I do live in a very sunny part of the world, and all of my testing was done on clear sunny days, so your mileage may vary depending on local weather conditions, with longer charge times for charging through a window or on overcast days.
According to Solpro, the Helios Smart uses Maximum Power Point Tracking Technology (MPPT), which optimizes charge times and is said to boost performance:
"Since solar conditions vary greatly during the course of the day MPPT balances the input from the panels to the battery to maximize the power the panels can feed into the battery. This boosts charging performance even in less than ideal conditions."
One claim that I couldn't verify, other than to say it works as advertised, was the "smart" charging feature that is said to "prioritize charging between its internal battery and all connected devices to ensure a full charge in the shortest time," while also allowing users to change the priority by pushing the charge button. The Helios Smart features pass-through charging, which is said to reduce the amount of electricity needed by directly "sending connected devices the voltage they need" instead of charging the internal battery first and then using the battery to charge devices.
The other claim that I couldn't verify (because I don't own any wearable devices) is that it is said to work well with wearables, which are fast becoming a popular choice for personal electronics:
"We’ve noticed that many people have encountered problems charging their wearables. The batteries in these devices are smaller and have less of a power draw when charging. If the draw is too small a typical battery bank might not even know it’s there. Helios has been engineered to recognize headsets, fitness trackers, and other wearables so that they will receive a full charge."
The Solpro Helios Smart was originally listed for $159 USD, which seemed a bit high before I actually used one, but the price has now been reduced to $119 USD, and in my opinion, is well worth every penny of it. The Helios Smart has a one year warranty, comes in three color options for the cover (white, black, and orange), and is available through the Solpro website or on Amazon.com (where it's currently listed for as low as $81, which is below the price on the company website).
[EDIT: The units I mentioned above as being available for a lower price at Amazon.com are actually the older model, with a 4500mAh battery, so they aren't the same as this one. The new units are priced at $159 at Amazon.com, and appear to be temporarily out of stock.]
[Disclosure: Solpro sent me a review unit of the Helios Smart, but all opinions and/or errors in this post are mine.]