The peak watt figure is a bench value, not a field promise
The headline on a folding panel is a peak watt figure, and it is a laboratory value. Makers publish it under standard test conditions — a defined irradiance, a defined cell temperature and a defined air mass — which the panel meets on a bench, not on a pitch at half past four in October. Read it as a way of ranking panels against each other, not as a promise of what will reach a battery. What you can act on is the rest of the datasheet. Cell type and the stated conversion efficiency tell you how much panel you carry for each watt. The output ports decide compatibility: a USB-C socket advertising a Power Delivery profile charges a phone or a laptop directly, while a barrel or proprietary DC output is aimed at one power station and needs the right lead. Ask whether a charge controller is built in or lives in the power station, because a bare panel wired to a battery is not a charging system. Then the physical facts: folded and unfolded dimensions, weight, and the kickstand, since the angle you can set is what actually changes yield through the day. An ingress rating, where one is published, usually covers the panel face while the junction pocket is rated separately or not at all. We compare stated peak output in watts under standard test conditions, cell type and stated efficiency, port set and Power Delivery profiles, whether a controller is included, folded and unfolded dimensions, weight, and stated ingress rating.
10 W · 24% monocrystalline · IP67, junction box excluded · 300 g (10.6 oz) · USB-A only
The smallest and lightest panel in this group — ten watts in three hundred grams — with a 24 per cent cell efficiency, an IP67 face and a single USB-A socket.
Best for: A phone and a head torch on a multi-day walk, and nothing larger
≈ $25
28 W · 25.4% N-type cells · two USB-C and one USB-A, 5 V/4.8 A total · IP44
The highest stated efficiency in this group at 25.4 per cent, from N-type cells on a shadow-free face — and the only listing here that says outright it will not charge a laptop or a power station.
Best for: Three phones at once, and nothing bigger
≈ $75
40 W · QC3.0 USB-A + PD2.0 USB-C 18 W each + 19 V DC 40 W · IP67 · 800 g (28.2 oz)
The only panel in this group with three kinds of output and a Power Delivery profile — forty watts through a 19-volt DC port, or eighteen each through USB-C and USB-A.
Best for: A small power station and a phone from the same panel
≈ $57
28 W · SunPower MAXEON cells, "24% increase" not 24% efficiency · 2 stands · dual USB-A
The only panel in this group with adjustable stands and a current checker — and the only one whose twenty-four per cent is an increase over other cells rather than an efficiency.
Best for: A pitch where the panel is set up, angled and left for the day
≈ $130
This family belongs to the walking and light kit — see everything that has to work with it.
Stated peak output is the panel’s ceiling, measured under the test conditions the maker publishes beside it.
Folded dimensions decide what straps on without getting in the way, and that is where the panel spends its days.
Because it is measured under the test conditions stated. Thin cloud, an off angle and heat all take a share.
The voltage steps negotiated with the device plugged in. They are published because they decide the real speed.
The technology used, published by the maker. It explains part of the stated efficiency and of the low-light behavior.
To charge a battery directly, yes. Controller included is published on every entry.
The port set is published entry by entry: USB outputs, DC sockets, dedicated connectors. It decides compatibility.
A panel strapped to a pack changes angle constantly, and so changes output. Many people charge a power bank at a stop instead.
The limits published by the maker are on the entry. This site does not add to them.
That depends on the port set and the controller. The conditions published by the maker are what count.
Peak output is only reached under the test conditions published; the rest of the time it is the Power Delivery profiles and the port set that decide what actually enters the battery.
The table keeps only what four items in five declare. A half-empty column hands an advantage to whoever kept quiet.
| Model | Price | Cell type | Port set | Power Delivery profiles | Stated peak output |
|---|---|---|---|---|---|
| FlexSolar E 10 W folding panel | $25 | High-efficiency monocrystalline A+ cells with ETFE film lamination | One built-in USB-A port at 5 V / 2 A maximum | None. USB-A only, with a smart IC that identifies the connected device | 10 W maximum under direct sunlight |
| FlexSolar FLC-E6 40 W folding panel | $57 | Advanced monocrystalline cells with ETFE laminate coating | Three: a QC3.0 USB-A and a PD2.0 USB-C at 18 W maximum each, plus a 19 V DC port at 40 W maximum. The only DC output in this group | PD2.0 on the USB-C port at up to 18 W. The only Power Delivery profile published in this group | 40 W, with the 19 V DC port rated at 40 W maximum |
| BigBlue BB 401 28 W folding charger | $75 | Advanced N-type solar cells on a shadow-free surface with no metal lines on the front panel, stated for superior low-light efficiency | Three: two USB-C and one USB-A, each at 5 V / 3 A maximum, collectively 5 V / 4.8 A | None published. The USB-C ports are rated 5 V / 3 A, which is not a Power Delivery profile | 28 W |
| ELECOM NESTOUT MPA-NEST-S014OV, 28 W, 4 panels | $130 | SunPower MAXEON cells, named by maker and series | Dual USB-A | None. USB-A only | 28 W of power generation, across four panels |
Specifications: manufacturer sheets for camping and hiking gear and the matching Amazon product pages. Prices and availability: Keepa. Every figure in this table names its source.
Most recent revision in this category: October 8, 2026.
Prices in these summaries were read on the dates each review gives. The live figure sits beside every product.
