This post contains affiliate links. If you buy through our links we may earn a small commission — at no extra cost to you. This never influences our recommendations.
The BigBlue 28W is a foldable solar charger with two USB-C ports and one USB-A port. It has no battery. It sends sunlight straight to your phone, power bank or other small gadget.
It’s popular with hikers and emergency kits. Here’s what it can charge, how fast, and where it falls short.
Specs at a Glance
| Spec | BigBlue 28W Solar Charger |
|---|---|
| Rated power | 28W |
| Ports | 2 x USB-C, 1 x USB-A |
| USB output | 5V/3A per port, 5V/4.8A combined |
| Cells | N-type, up to 25.4% efficiency (manufacturer claim) |
| Weight | About 1.5 lb |
| Folded size | 11 x 6 x 1.4 in |
| Water resistance | IP44 (splash only; USB box is not waterproof) |
| In the box | 50 cm USB-C cable, carabiners, manual |
| Battery | None |
What 28W Really Means
The 28W rating is the panel’s output in ideal sun. The USB side is limited to 5V/4.8A combined, which works out to about 24W, and real sunlight rarely gives you the full amount.
Our rough estimate: expect around 8–15W in good direct sun. That’s enough to charge a phone in a couple of hours. Field reports of a phone going from 20% to 80% in about two hours fit that range, but they’re anecdotes, not lab tests.
Clouds, haze and shade cut output sharply. The unit has no battery, so charging pauses whenever the sun does.
What It Can and Can’t Charge
It works for: phones, power banks, headlamps, GPS units, earbuds and small cameras.
It doesn’t work for: laptops and power stations. BigBlue says its output isn’t enough for either. For those, step up to a bigger foldable solar panel.
The best use is charging a power bank during the day, then charging your phone from the bank at night. That’s the usual advice from long-distance hikers, because the bank keeps charging through passing clouds.
BigBlue 28W Solar Charger Review
BigBlue 28W Solar Panel Charger (Dual USB-C and USB-A)
The appeal is simplicity. You unfold it, hang it from the carabiners, plug in a cable, and a blue LED confirms it’s charging. At 1.5 lb it packs into a backpack without much thought.
The catch is that this isn’t a waterproof panel. Rain and splashes are fine, but BigBlue says the USB junction box is not waterproof, so keep it dry. Multiple devices also share the same total output, so plugging in three things slows each one down.
It’s also not the lightest option. Ultralight backpackers may find 1.5 lb hard to justify. The listing shows 4.3 stars from nearly 10,000 ratings. Output varies a lot with sun angle, so test it in direct sun when it arrives.
| Pros | Cons |
|---|---|
| Two USB-C ports plus USB-A | No battery, so charging stops when the sun does |
| Folds to 11 x 6 x 1.4 in | USB box is not waterproof |
| Carabiners for hanging on a pack | Not for laptops or power stations |
| 4.3 stars from nearly 10,000 ratings | Output drops heavily in clouds or shade |
Best for: Campers, hikers and emergency kits that need to keep a phone and a power bank charged.
Full details and current price: BigBlue 28W Solar Panel Charger on Amazon
If you want to compare chargers that include a built-in battery, see our guide to the best solar power bank. Hikers should also check the best solar power bank for backpacking.
Frequently Asked Questions
Can the BigBlue 28W charge my phone directly?
Yes, in direct sun. If the sun fades, charging pauses and may restart on its own. A power bank in between smooths that out.
Does it have a battery?
No. It only passes power through while the sun is on the panel, so you need to charge a device or power bank to store the energy.
Can it charge a laptop or power station?
No. BigBlue says the output isn’t enough for either. See our portable power station with solar panel guide for those.
Is the BigBlue 28W waterproof?
It’s rated IP44, which means splash resistant. The USB junction box isn’t waterproof, so keep it out of rain and puddles.
Does it work through a window?
Not well. BigBlue advises against using it behind a window or windscreen, because the glass cuts output.
Final Verdict
The BigBlue 28W is a solid pick for keeping phones and power banks topped up on camping trips, hikes and in a hurricane kit, as long as you treat it as a sunny-day tool with no storage. If you need to run a laptop or want power after dark, a power bank with built-in solar or a bigger panel and power station is a better fit.