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Reviews > Electronic Devices > Solar Chargers > Bushnell SolarWrap Mini > Test Report by Rick Dreher
Bushnell Solar Wrap Mini
I enjoy going high and light and frequently take shorter "fast- packing" trips. My longest trips are a week or so. I've lightened my pack load because I enjoy hiking more when toting less, I can go farther and over tougher terrain, and I have cranky ankles. I use trekking poles and generally hike solo or tandem. I've backpacked all over the U.S. West and now primarily hike California's Sierra Nevada. My favorite trips are alpine and include off-trail travel and sleeping in high places. When winter arrives, I head back for snowshoe outings in the white stuff.
Product Information & Specs
Model: Powersync SolarWrap Mini
Introduction & Description
The Bushnell Powersync SolarWrap Mini is a combination storage battery and flexible photovoltaic (PV) panel that charges electronics in the field. For folks like myself, the SolarWrap represents the realization of something "invented" many times philosophizing by a campfire: "What if I never had to carry spare batteries and I could just charge my stuff?" It just took a couple decades for the technology and the smart people to catch up with our campfire brilliance.
"Back in the day" I hiked with just one electrical device: a flashlight. Unlike my sad-sack, frequently broken, double D-cell Ray-o-vac, today's lightweight LED headlamps are vastly more powerful and reliable and yet, they still need a battery and, depending on the amount it's used, either spares or field-recharging. Of course my electronics have grown beyond the headlamp, like Bermuda grass in a garden, and I now carry a bunch of electrical gizmos. Surveying the pile, some require me to carry extra batteries (camera, GPS, etc.) while others don't even have replaceable batteries (cellphone, MP3 player). My headlamp straddles the two worlds and I've installed a rechargeable battery in lieu of the stock AAA cells, making it rechargeable as well.
In sum, for at least three of my gizmos, a remote charger might keep them powered indefinitely, regardless of trip length. Hello, SolarWrap Mini.
As noted above, the SolarWrap Mini is a pliable PV panel attached to a storage battery. When collecting solar power, the Mini is a long, narrow flexible sheet attached to a cylindrical battery at one end. When stowed or just charging a device, the PV panel rolls up around the battery to make a small cylinder.
The Mini is designed to charge electrical devices both directly from solar power and while the sun isn't shining, via the built-in storage battery. The battery itself can be charged either by the PV panel or using external power connected to the micro-USB port. A target device connects to the Mini's output USB port, either directly or via cable.
The Mini ships with a USB-to-micro-USB connecting cable and instructions.
Instructions & Web Support
The Mini shipped with a "Quick Start" guide describing operations and listing specs, and instructions are printed on the device itself. The Bushnell website product page has a description and the specs. A question that remains unanswered by these resources is whether the Mini can simultaneously charge a device from the battery AND the sun. Might be a factor for higher-capacity devices.
Trying It Out
Charging another device: To charge a gadget, connect it into the Mini's "output" USB port, either directly or via cable. Charging begins automatically, and with no notice from the Mini--the LED is either off or it glows red at times it's simultaneously self-charging. Because the Mini does not indicate output charging status, whatever indicator is on the target device itself is the only way to verify 1. charging is occurring and 2. when it's complete.
Storage When not actively charging from the sun, the Mini can be rolled up and still charge another device. When packing it away, Bushnell recommends using the protective caps for storage to keep debris and moisture from the USB ports.
The SolarWrap Mini extends the concept of self-charging battery beyond what I've used in the past. While some competing devices only use a small area on the battery pack itself to house a rigid PV panel, the Mini deploys a significantly larger solar array, yet weighs and stows to similar size and weight. I'm hopeful the collector can be used even on the go and not just in camp. We shall see.
Field Locations & Conditions
I carried the Powersync SolarWrap Mini on ten backpacking days over two trips-one three-day and one seven-day. I also did "bench-testing" at home to get a better sense of its operation, capabilities and specifications. All backpacking was in California's Sierra Nevada, between 7,000 and 9,000 feet (2,100 - 2,750 m) elevation in sunny to partly cloudy weather. Home testing was at sea level.
Season, altitude, latitude, weather: These four variables affect the amount of solar power available for recharging. In addition to the above data, all my testing and trips have been between 38 and 39 degrees north latitude.
Charging the Mini: In controlled tests at home I was able to verify the factory's charge time estimates within a variation of an hour or two. Charging from "empty" takes between four and five hours using the USB input, and about half a day (ten to twelve hours) placed in the August sun, unattended, during the day at 38 degrees N latitude, sea level. While photovoltaic (PV) cells put out the most power aligned perpendicular to the sun's rays, setting the Mini out and leaving it for the day means the light is striking it at an angle most of the time. In the field, I am usually able to turn the Mini to directly face the sun as it travels across the sky (more, below).
I gathered a group of potential backpacking electronics to evaluate whether they're compatible with the Mini, and also researched their battery capacities.
Can be Connected (battery capacity)
iPod Nano Gen 7 (220 milliamp-hours [mAh])
Kindle Fire (4,400 mAh)
Kindle Keyboard (1,900 mAh)
Motorola Razr Maxx (smart phone) (3,300 mAh)
Petzl Core (headlamp battery) (900 mAh)
Can't be Connected
Digital camera with proprietary battery
GPS receiver with two AA batteries
Satellite transceiver with two AA batteries
220 to 4,400 mAh is a huge range in battery size and exemplifies the challenges inherent in charging consumer electronics. As to the three gadgets that cannot be charged, it's the lack of a suitable adapter that prevents the camera battery and the rechargeable AA batteries from consideration in this test. (USB AA rechargeable cells exist, but are very low capacity.)
Lacking a storage specification for the Mini's battery, I've tried to ballpark one. It can fully charge the Petzl Core at 900 mAh but not the Kindle Keyboard at 1,900 mAh, so is probably between these two values. (Note: this value is for the battery alone, with no additional solar charging.)
One of my initial questions was whether the Mini can simultaneously charge a device and gather solar energy and the answer appears to be "yes." When placed in the sun while charging something else, the red charge light also illuminates (it is off when only charging, and not collecting). After the device is recharged and unplugged, the Mini can sometimes completely recharge itself within an hour or two afterwards, further indicating it's not exhausting the storage battery (otherwise, it would take the Mini many hours to self-charge).
In the Backcountry: I used two backpacks during testing but have not devised a safe way to attach the Mini to the outside without risking being snagged while hiking, so I limited solar collection for in camp. On the other hand, I charged devices while hiking with them stowed safely inside the pack, cabled together. That works like a champ.
Rechargeable items used daily on my trips were the Petzl headlamp and the Motorola phone, with the iPod and Kindle Keyboard getting occasional use. My target was to "top off" the headlamp and phone daily, along with the Mini's storage battery, and the iPod as needed. (The Kindle battery lasts so long it turns out I don't actually need to recharge it on the go, but I at least know I can.)
My workflow is simple: unfurl and set up the Mini in the morning or afternoon sun and attach the target device, then watch the battery meter for full charge. If needed, switch to another target device, otherwise, top off the Mini's internal battery.
During a seven-day trip I was able to keep all four devices charged-the phone, the headlamp, the iPod and the Mini itself. A couple of layover days made this extra easy, but I'm confident that even breaking camp and hiking daily, I can achieve the same result. The key seems to be not running electronics to exhaustion between charges but instead, keeping them fully charged, or as close as possible.
The iPod and phone self-monitor when charging and shut down when fully charged (presuming they're not turned on during charging). The Petzl battery does display charge status using colored LEDs but doesn't shut down when it's completely charged, a minor annoyance because it continues to draw power from the Mini.
The Bushnell SolarWrap Mini can keep a group of electronics running indefinitely, provided there's ample sunlight to keep it going.
Long-Term Test Locations & Conditions
My California backpacking season had wrapped up the field report, but I was lucky enough to conduct change-of-venue tests on Maui, Hawaii. (Tough duty, admittedly, but I'm just that sort of guy to go the extra mile.) I used the Mini at the beach, at our rental and on Haleakala, Maui's volcanic summit. Weather was mostly sunny; altitudes ranged from sea level to about 10k feet (3,050 m); and temperatures from 60 to 85 F (16 to 30 C). Directly impacting solar power collection, longitude was 20 degrees, 40 minutes, which officially put me in the Tropics.
Back home (38 degrees N and sea level) near the year's shortest day, I also tried the Mini for a seasonal and geographic comparison.
I used the Mini as before: charging it when convenient and charging my gadgets as needed. In Hawaii the gadgets were limited to my phone and two iPods and when hiking, I collected sunlight when stopped, not on the go because the backpack didn't accommodate the unfurled outside. There's no obvious way to keep it from flapping and while the sun.
Wear and Tear
Accumulated minor scuffs and dirt are the only signs of use; otherwise, the Mini is good as new. Li-ion batteries like the Mini's all weaken with time, but I didn't observe any capacity loss over these six months-if there was any it's too subtle to notice.
Reiterating the field report, the Bushnell SolarWrap Mini can keep a group of electronics running indefinitely, provided ample sunlight and charging time to keep it going, and an exposed sunny location to deploy it. The Mini is well built and easy to store, carry and use. Latitude of use does affect its capabilities: while performance during the California summer is quite satisfactory (sun angle is high and the days are long) wintertime performance here drops off noticeably and the Mini can't support as many devices, or charge those with very large batteries. But in the tropics and it gives the best performance of all.
The Bushnell SolarWrap Mini is one of three PV-battery devices I own, but the only one with a large, flexible solar panel. I'm now a fan of skipping spare batteries and recharging in the field, and will likely continue to use the Mini for this purpose.
Grateful thanks to Bushnell and BackpackGearTest.org for the opportunity to test the SolarWrap Mini!
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