In the heart of the Goal Zero Yeti 400 lies a 12-volt, 33-amp/hour...
Although the word “offgrid” is part of the name of our magazine, and we cover and discuss many products and techniques that can help you survive without access to electricity, there’s no denying that juice powers some wonderful devices.
So what can you do when you expect to be far from outlets, but still need power on tap? More specifically, what if you need a lot of power and AC capability? Jackery has a solution: the Explorer 500. They call it a portable solar generator, and while you can charge it with a solar panel, it’s basically a giant battery. Not one of those old-fashioned, boat anchor, lead-acid batteries that you might find in cars and some other high-capacity generators, either. It features lighter, more compact, and more resilient lithium-ion cells, just like smartphones, laptops, and Tesla cars.
Electricity is essentially the flow of electric charge, which we utilize to power our homes, offices, and portable devices. Voltage, measured in volts, refers to the potential energy or difference in charge between two points. Current, measured in amperes, refers to the rate at which charge is flowing. Multiplying the two together results in an expression of power, measured in watts (V x A = W).
Your house is powered from your local electrical grid with AC (alternating current), whereby the electric current repeatedly reverses direction, alternating back and forth at a certain frequency. On the other hand, DC (direct current) flows in only one direction, as used to power electronic systems and as found in batteries.
Many items are designed to be plugged into an AC outlet. So if you wish to power them with a portable battery unit, it must be able to convert the DC output from its battery to AC for the appliance or device to use, via a component called an inverter.
Power requirements for various devices span a wide range. A 100-watt light bulb, not surprisingly, draws about 100 watts. A desktop computer might draw several hundred watts. A microwave could wolf down over 1,000 watts. This is no problem at home — a typical 15- or 20-amp 120-volt power circuit in your house can deliver about 1,400 to 1,900 watts of continuous power (e.g. 15A x 120V x 80 percent for a continuous load as a rule of thumb).
However, while hairy-chested gas-powered generators can replicate this level of power delivery, batteries like the Jackery generally can’t put out that much power. The Explorer 500 is rated to deliver peak AC output of 500 watts and continuous output of 300 watts (110 volts at 2.6 amps). So don’t expect to use power-hungry appliances and tools with it.
Above: Our trusty old Ono Sokki FFT (Fast Fourier Transform) analyzer plots amplitude versus time, showing a nice sine wave from the Jackery. Voltage values look low, because we used an attenuated oscilloscope probe.
Jackery says the capacity of this beast is 500 watt-hours, so theoretically you could power a 50-watt device for 10 hours or a 500-watt item for one hour. For an extended continuous test, we used the Explorer to run a retina MacBook Pro 15 for an entire work day, consisting of watching work-related videos, work-related surfing of the web and social media, writing articles, editing photos and videos, rendering video projects, playing a few work-related games, and watching more work-related videos. From a full charge, the Jackery lasted 10.5 hours (roughly 10 percent of capacity per hour) and its built-in LCD monitor reported power output typically ranging from 20 to 60 watts. This was pretty consistent with Jackery’s stated specifications, assuming some efficiency loss.
To test more peaky power needs, we used the Explorer to run studio strobe flashes that bumped up against its peak AC output. We powered two strobes on a photo shoot with a power strip plugged into the Jackery’s single AC outlet. There seemed to be a dip in power after each time the strobes fired, but the big battery kept on trucking throughout the shoot. With the heavy demands on the battery, the Jackery’s cooling fan also kicked in.
Note also that the unit doesn’t actually connect to the third grounding prong on plugs; there’s just an empty plastic recess to accommodate the prong. This seems unlikely to present any issues, especially given the Explorer’s overall power output limitations, but devices that sense and require a proper ground may not work.
Jackery says that the Explorer’s AC output is a pure sine wave, as you’d expect from your home’s outlet and high-end backup power systems for computers and other sensitive electronic equipment. However, an online publication’s review of the similar Jackery Power Pro last fall found that it wasn’t producing a clean sine wave when connected to an ocilloscope. We wanted to check if Jackery had improved the quality of the AC power output along with the product’s name. So, we spent some time on the lab bench with an Ono Sokki FFT (Fast Fourier Transform) analyzer. We’re pleased to report that the Explorer’s AC signal was a clean sine wave, confirmed with the FFT analyzer’s plots of voltage amplitude versus time and frequency.
For more pedestrian DC power needs, the Explorer also has two USB ports, a 12-volt car socket, and two 6mm 12-volt DC sockets. Recharging small items like an iPhone were child’s play with the massive battery, like refueling a motor scooter with a KC-135 Stratotanker.
With such a large battery, charging the Explorer is a non-trivial consideration. The specification for its charging port is 25.5 volts, so it requires a hefty power source to replenish its lithium-ion cells. The included AC power adapter weighs 1 pound and pushes 25.5 volts at 3.5 amps; the math lines up perfectly with the Explorer’s display, which indicated an input of 89 or 90 watts when plugged in. Jackery says a full charge should take six to seven hours; in our testing, it took almost exactly six hours each time.
Alternately, for when power outlets aren’t available, Jackery offers optional solar panels. We tested their large 102-watt panel, which folds in fourths from a sail-like 40 by 31.5 inches to 20 by 16 inches and is secured by magnets and a zippered sheath when folded. It has two USB outlets, USB-A and USB-C, as well as a connector that takes an extension cable to plug into the Explorer. There were two cable lengths included with our press loaner; the short 12-inch one was faulty but the long 10-foot cable worked fine. On sunny California days in springtime, the Explorer showed that it was receiving 45 to 57 watts from the solar panel. At best, we’d recharge about 10 percent per hour in midday, averaging closer to 5 percent as the sun crept on. Jackery notes that total charge times of seven hours or less are possible, but we weren’t able to achieve sufficiently high-input wattage to charge that fast. Note that Jackery has updated its solar panels, now offering a 100W variant which offers similar performance to the older model that we tested. It also replaces the fabric outer shell with hard plastic.
While lithium-ion cells are great, they don’t last forever and lose effectiveness over time — just ask Apple about its Batterygate controversy. Jackery estimates that the Explorer’s battery will last approximately 500 full recharging cycles.
In the field, the Explorer worked as promised, without any fuss. The illuminated display shows power output, input, and battery status in percentage. This was very handy to keep an eye on power consumption (or charging) and to have a handle on how much longer the battery might last. However, like a cheese-eating surrender monkey, it gives up the ghost silently; we’d have liked an audible indicator when the battery runs out. There’s an LED light built into the unit as well, convenient when you’re trying to deal with a tangle of cords and devices at night.
The single AC outlet was an inconvenience; we successfully used a power strip, but that’s one more item to worry about and misplace when you most need it. In any case, you should remain cognizant of the total load you put on the system.
We thought the car socket would be handy to use a cigarette lighter as a firestarter. Unfortunately, none of the lighters we had on hand (from an old Ford truck and an old Honda) worked — it appears the contacts on the lighters were recessed too far for the Explorer’s socket. But various other 12-volt car accessories worked well, including a portable refrigerator that’s been a family favorite on long trips over the years.
While somewhat heavy and bulky, the solar panel worked dependably. You can drape it over a tent, prop it up, or use the metal grommets to latch it to something, like a roof rack.
The Explorer isn’t weather-proof, with its exposed fan and sockets, but held up fine in regular use. It got banged around in the back of vehicles, along dirt trails, and at camp sites, collecting scratches, but continuing to serve up juice. Additionally, its stated operating temperature to supply power ranges from 14 to 113 degrees F, and from 32 to 104 degrees F for charging, so be mindful of this if you experience temperature extremes in your area.
At over 12 pounds for the battery and over 9 pounds for the solar panels — not to mention their bulk — the system wasn’t particularly practical for traveling on foot. It has a nice rubber carrying handle, but isn’t otherwise conducive to being humped. However, it did function nicely as an improvised kettlebell for exercising in the field.
So the Explorer 500 seems best suited for relatively static or vehicle-based applications — emergency or backup power during outages, supplemental power source, car-camping trips, events at venues without power outlets, and so forth. We read online reviews from folks who also use it for medical equipment and astronomy. For long-term survival use, though, we’d pick a more powerful gas generator over a solar-powered battery pack like the Explorer to service electrical needs. But as a dead simple, clean, quiet power source for items that aren’t overly power hungry, the Jackery Explorer 500 is a very handy tool. And its ability to be recharged via solar panels can help to lower your reliance on consumable fuel sources — an important consideration if a disaster leads to chaos at local gas stations.
Jackery Explorer 500 and 102W (tested) Solar Panel
10.6 by 6.7 by 12.5 inches (battery pack)
20 by 16 by 1 inches (solar panel, folded)
12.4 pounds (battery pack)
9.3 pounds (solar panel)
$599 (battery pack)
$499 (100W solar panel)