REVIEW – The more portable batteries and power packs pile up, the more a cheap, or free, way to keep them all charged becomes necessary. Rather than hand over a paycheck to Seattle City Light every month, I went hunting for an effective solar panel kit, and the FlexSolar 120W Foldable Solar Panel Kit might be the answer. This affordable, versatile kit comes with high-efficiency solar panels that are easy to carry around, plus a Solar Charge Controller that can charge nearly everything I own, right up to and including my car battery. There are a few catches attached to the low $199 price tag, but on the whole this kit packs in a ton of functionality along with plenty of free power.
The Basics
The FlexSolar 120W Foldable Solar Panel Kit is a portable, four-panel monocrystalline solar setup with a built-in junction box plus a standalone Solar Charge Controller, made for short-term off-grid charging while camping, hunting, or RVing.
Unboxing
The kit ships in a display box, which raised some worry at first since solar panels can be delicate if mishandled. Fortunately, everything was well cushioned in foam and arrived undamaged. The box lays out all the kit’s features along with its technical specs.
What You Get
- 120 W Foldable Solar Panel
- 20 A (12 V/24 V) PWM Solar Charge Controller
- Carrying Case
- User Manual
- 2 x 1 ft. (0.3 m) cables with Anderson to Wire
- 1 ft. (0.3 m) cable with Anderson to Alligator Clip
- 1 ft. (0.3 m) cable with Anderson to DC5521 Male Connector
- 10-in-1 Interchangeable Connectors
- 7.9 x 5.6 mm
- 6.0 x 4.3 mm
- 6.3 x 3.0 mm
- 5.5 x 2.5 mm
- 5.5 x 1.7 mm
- 4.8 x 1.7 mm
- 4.0 x 1.7 mm
- 3.5 x 1.35 mm
- 3.0 x 1.1 mm
- 2.5 x 0.7 mm
By the Numbers
- Solar Cell Type: Monocrystalline
- Dimensions: (L x W x D)
- Unfolded: 65.1 x 22.2 x 0.2 in (1653 x 564 x 564 x 5 mm)
- Folded: 22.2 x 14.1 x 1.6 in (564 x 359 x 41 mm)
- Product Weight: 10.8 lbs (4.9 kg) with junction box and accessories
- IP Rating: IP65 – protection against accidental contact and ingress of dust along with water jets from any direction
- Output ports: USB 2.0, USB 3.0, USB-C (PD 60 W), Anderson (10 ft. hardwired cable)
- Charge Controller: 12V/20A PWM
- Open Circuit Voltage (Voc): 23.7 V
- Short Circuit Current (Isc): 6.36 A
- Maximum Power (Pmax) 120W
- Maximum Power Voltage (Vmp): 19.8 V
- Maximum Power Current (Imp): 6.06 A
- Cell Efficiency: 22%
- Power Tolerance: ± 10%
- Operating Temperature (F/C): -4°F to 149°F (-20°C to 65°C)
- Temperature Coefficient (Pmax): -0.45 %/K
- Temperature Coefficient (Voc): -0.32 %/K
- Temperature Coefficient (Isc): +0.02 %/K
- NOCT (Air 20°C, Sun 0.8kW/m², Wind 1m/s): 45±2°C
- Standard Test Conditions: 1000 W/m2, 25°C, AM1.5
Design and Build
The FlexSolar 120W Kit’s design mirrors most portable solar panels with a couple of twists. One thing that sets it apart is the included carrying case, a plain fabric bag with two zippers running along the panel edges and a heavy rubber carrying handle fixed right to the folded panels.
What makes the case a real bonus, on top of the extra protection it gives the panels, is the Velcro pouch up front, ideal for keeping the FlexSolar accessories close and secure.
Inside that pouch is a little elastic loop sized just right for the Solar Charge Controller, a thoughtful design touch.
The Solar Charge Controller bundled with the kit is fairly basic, but it clearly makes the kit more useful. It shields connected devices from over-charging, over-voltage, and short circuits, and it lets you charge different battery types, like the lead-acid batteries found in cars or RVs. The controller has three buttons for working through its menus and an LCD screen, plus two USB ports for charging devices like tablets or phones directly.
Alongside the controller, the FlexSolar comes with four cables sporting Anderson connectors, typically used to carry high-power electric current. Two of the cables are Anderson to bare wire; the bare-wire ends feed into the controller’s terminals, while the Anderson ends join up with any other Anderson connectors.
The Anderson to Alligator Clip cable is what hooks the charge controller up to batteries.
The Anderson to DC5521 cable makes use of any of the 10 adaptor plugs and runs the Anderson cable from the solar panel junction box to nearly any power station.
Pull the panels out of the case while they’re still folded and one side is shielded by heavy fabric.
A front flap holds the panels shut with Velcro.
On the back of the panels, tucked into a built-in zippered mesh bag, is the attached junction box.
The junction box has a hardwired 10-foot cable ending in an Anderson plug for tying into power stations via the 10-in-1 adaptors. It also carries three charging ports: a USB 2.0 port at the end of a coiled cable, a USB 3.0 port, and a USB-C port that can charge some devices at 60 watts. That 60W PD USB-C port even allows charging a power station from both it and the hardwired Anderson cable at once, as long as the unit accepts charging from both. With an optional cable, the junction box can also link two 120W panels in parallel.
Fully unfolded, the panels stretch to about five and a half feet long. The FlexSolar panels use a monocrystalline inlay, which is more efficient than older solar cell inlays and reportedly delivers a stated 24% efficiency.
Small fabric loops line the panel edges, letting them hang off the side of a tent or car. Being portable panels is probably why they skip the grommets normally found on panels this size, which would let you screw the panels down to stop theft or shifting. For a portable kit, security isn’t as big a deal since you’re constantly setting it up and taking it down. Plans to use the FlexSolar kit for car camping, most likely spread across a windshield or roof, make the lack of grommets a non-issue, especially at this price.
The panels sit safely inside sealed hard plastic sleeves, and dirt wipes right off with soapy water. The one worry is that the panels and junction box carry only an IP65 rating, meaning they aren’t fully waterproof, just resistant to direct water jets and dust. The junction box getting wet and taking damage while in use is a real concern.
Getting Started
How the FlexSolar kit gets set up depends on what it’s being used for. To charge batteries, say for an RV or car, the Solar Charge Controller has to be wired correctly first. Back the screws out with a Phillips screwdriver and slide the bare-wire cable ends into the matching positive or negative terminals, then snug the screws back down to lock the cables in. Little icons above the terminals mark the solar panel power input, the power output to a battery, and the load output terminals.
The panels’ hardwired Anderson cable plugs into the cable running from the solar panel input. For a car battery, the Anderson to Alligator Clip cable connects to the battery port and the alligator clips clamp onto the battery terminals. The Solar Charge Controller must connect to the battery BEFORE connecting to the panels, or the controller gets damaged. Power from the battery wakes the controller up and allows moving through the menus to set it for whichever battery type is in use.
Without the Solar Charge Controller, anything that needs charging, a power station included, hooks straight to the junction box while the panels spread out in the sun. The junction box LED glows red while it’s pulling power from the sun and green whenever a device is plugged into the USB-C port.
The FlexSolar panels are meant to lie flat at 90 degrees to the sun, so they ship without any foldable stands or mounts. That might just be a marketing excuse for leaving mounts out, since mounts would normally be handy when the sun sits at different angles. In practice the built-in kickstand flap does prop one end up somewhat, which helps.
Living With It
Testing a solar panel kit in a city famous mostly for gray skies and rain wasn’t the smartest plan, but a few partly sunny days up on the building’s roof were enough to put the FlexSolar kit through its paces.
Spreading the panels out was dead simple, and charging a phone off the junction box came next, starting with the USB 2.0 port. The panel output measured about 5V, and it charged a Pixel 5 quickly even though it was only partly sunny.
The USB 3.0 port and the USB-C port got a try too. All three junction box ports steadily put out about 5V, which is genuinely impressive, since all of them can run at the same time to charge separate devices without any voltage drop.
With the Ampere app, the phone confirmed it was getting between 4 and 5V and averaging about 1045mA.
Next, the junction box ran straight into a Goal Zero Yeti 1000 Core Portable Power Station, reviewed back in September 2021, using the hardwired Anderson cable and the 8-millimeter connector.
The FlexSolar panels held a steady output of roughly 70 to 74 watts into the Yeti, well under the 120 watts they can hit in perfect conditions, but still impressive given the day.
A 60W USB-C to USB-C cable could also have been linked from the junction box to the Yeti’s 60W PD port to grab some extra charging power.
The one hiccup came from the 8mm adaptor plug. The assortment of connector tips is appreciated, but the plug’s length made it a bit wobbly, and it popped out a few times with barely a bump. Not a major issue, but it ended up getting taped down to keep it in place.
The FlexSolar and its Solar Charge Controller also went to work on an FJ Cruiser’s car battery, with great results.
The panels ended up laid across the roof of the FJ for convenience, basically the kind of setup that would get rigged in an emergency out in the woods with a dead car battery.
Once again wiring the controller to the battery before the panels, about 12V fed into the car battery. Given enough time the panels could fully recharge it, even while drawing from it to run other devices. A standard RV rig would have an inverter off the battery powering gear, with the controller and panels topping the battery back up as it drains. The controller’s USB ports can be put to work in this setup too.
And with even more juice needed, the USB ports on the solar panel junction box could run additional devices simultaneously.
Charging a car battery with solar power is a genuine game-changer, and it earned the FlexSolar a permanent place in the FJ’s emergency kit.
On the whole, the price, portability, and performance of the FlexSolar 120W Kit left a strong impression. It doesn’t just boost what a Goal Zero Yeti 1000 can do; it can top off every power bank around for as long as the sun keeps shining.
The Good
- Easy to set up and break down
- Included charge controller adds expanded functionality out of the box
- Multiple ports allow charging simultaneously from panels and charge controller
The Not So Good
- Panels and junction box are only IP65 rated, not fully waterproof
- No included or integrated stands for panels
The Verdict
The FlexSolar 120W Foldable Solar Panel Kit is an affordable, flexible alternative to most panels putting out similar power. The panels are sturdy, portable, and fast to set up, though better water resistance would be welcome. The included charge controller brings real value, allowing the kit to be configured different ways to match the moment. The 10-in-1 connector set, the charging cables, and the range of ports play nice with just about any power station, gadget, or power bank. Best of all, every bit of that versatility comes at the bargain price of $199. Whether it rides along as an emergency battery charger or forms the backbone of a simple RV setup, the FlexSolar 120W Foldable Solar Panel Kit is a great buy.
Price: $199.99
Product Link: FlexSolar
Source: The sample of this product was provided by FlexSolar
