Real-world power, well below the advertised 28W
The BigBlue 28W delivers real-world power well below the advertised 28W. Compared with three other panels under the same conditions (full sun, midday), it comes out at 10.5W, or 37.5% of its rated power: the lowest share of the four panels compared, while a notably cheaper panel reaches nearly its own advertised power under these same conditions. The same order of magnitude shows up separately in several countries and across several generations of the product since 2016: between 10 and 14W in full, well-angled sun, up to 13-14W at best when the panel is held perpendicular to the sun.
Under overcast skies, power drops much lower, between 2.5 and 6W depending on cloud cover. The panel still keeps producing in these conditions rather than stopping, and generally recovers quickly after a brief shading event (a passing cloud, the shadow of a tunnel or a tree), with no need to unplug and replug the devices.
Size and weight, the product's real strength
Folded, the BigBlue 28W is about the size of a magazine, roughly 28 x 16 x 3.3cm, and unfolds to around 84 x 28cm at a thickness of a few millimetres. The advertised catalogue weight is 680g; the real weight tends to sit between 580 and 670g, consistently under that figure. This size and weight make it one of the most compact panels in its rated power category, regularly cited favourably against smaller panels that do not offer a compactness gain proportional to their lower power.
Weather resistance: IP44, but not for the ports
The panel is IP44 rated, a resistance to rain and splashes that does not cover immersion. This rating covers the fabric and the main housing, not the USB ports or the ammeter housing on variants that have one, a nuance that the marketing emphasis on IP44 does not spell out. No immersion test or standardised resistance rating beyond this certification was found either, in any of the languages consulted.
Ports: several generations, one current configuration
One point is worth knowing before buying: BigBlue has sold different variants of its "28W" for several years, with port configurations that have varied across generations (two or three USB-A ports, mixed USB-A/USB-C ports, with or without a built-in ammeter). The current spec sheet for this model lists 2 USB-C ports and 1 USB-A port, up to 5V/4.8A combined, enough to charge up to three devices at the same time.
In at least two distinct cases, a device that was already well charged can lose a little charge into another device plugged in at the same time, rather than the other way round. This behaviour has not been confirmed across a large number of cases, but is worth keeping in mind for anyone planning to charge several devices at very different charge levels at once.
Build quality and lifespan
The advertised manufacturer warranty is 24 months. The build (reinforced fabric, stitching, carabiners) is generally judged solid, with no manufacturing defect reported on a recurring basis. One unit did, however, arrive faulty on delivery (scratches, a defective eyelet, flaking paint), the same unit where the lack of automatic recovery after shading also appears, which suggests an isolated unit rather than a design flaw. After around 3 years of heavy use, a failure (charging stops, signs of wear) also appears in two distinct cases, unrelated to each other. These cases remain isolated and do not allow for any conclusion about a general failure rate, but are worth knowing about.
A backup panel, not a primary power source
Given the gap between advertised and real-world power, the BigBlue 28W fits best as a backup solution: topping up a power bank during the day to have energy in the evening, rescuing a phone while hiking or in an emergency, without expecting a fast charge comparable to a wall socket. It does not suit anyone looking to power an energy-hungry device continuously or to quickly recharge several devices at once.
Price and availability
The catalogue price sits around €60 to €70 in France, with occasional promotions bringing it down to around €63. No product recall has been found for this model, either with the US consumer product safety authority or its European counterpart, although these databases could not be searched exhaustively and directly.
