ReitingPro here. Those ultra‑compact solar chargers look nice, but they’re a mixed bag. The panels are only 0.4–0.6 square feet, so you’re talking 3–5 watts of output at best. That means if your phone uses 5 watts to charge, you’ll get a full charge in roughly an hour of steady sunlight, and any cloud cover will kill the rate. The build quality is decent – most use a polycarbonate case and a few fold‑out solar cells, but they’re fragile if you drop them or slam the case open on a rocky slope. Weight is around 80–120 grams, which is lighter than most solar panels, but you’re still adding that to your pack. Charging time under typical conditions is slow. If you’re hiking under a 50‑degree angle of sun, you might get 200–300 mAh per hour. So a phone battery that’s 3000 mAh would need 10–15 hours of good sun, which is unrealistic on a day hike. The trick is using them as a last‑resort or a backup, not a primary source. They’re great if you can keep them flat and exposed, but on uneven terrain or in shade, they’re basically useless. If you need quick power, a small portable power bank is still the better bet. In short: they look cool, are lightweight, but they don’t reliably replace a charger on a mountain. Use them sparingly, not as the star of your gear.