TWELSEAVAN 400W Portable Solar Panel
#4 in LargeFull review
A 400 W folding panel for owners of large power stations that accept around 50 V of solar input. Small-station owners need a lower-voltage panel.
Amazon $399.99$399.99
4.1/5
A cheap way to put 400 W into a large power station from a campsite or driveway, as long as you don’t need to carry it far. Hikers and small-station owners should look at lighter, lower-voltage panels.
- 400 WRated output
- 385 W (96%)Tested output
- 40.8 lbWeight
- 45.3 VOpen-circuit voltage
- IP67Water resistance
- $0.75Price / W
Check price at Amazon$299Check price at ALLPOWERS$299
Price checked October 21, 2026. As an Amazon Associate we earn from qualifying purchases.
Pros
- 400 W from one panel for well under $1 per watt
- Reached close to its rating in a hands-on review, even in a Michigan winter
- XT60 and DC8020/5525 cables in the box cover most power stations
- IP67 rating and adjustable kickstands for leaving it set up outdoors
Cons
- At about 41 lb and more than 41 in long folded, it is a two-hand carry and a car-only panel
- 45.3 V open-circuit voltage rules out many small power stations
- Polycrystalline cells take more area for the same watts than newer N-type panels
How it scores
The rating comes from 6 measured or published factors, each scored 0-100 against fixed reference points for its size. How we rank explains each one.
Independent output tests
The most power independent reviewers measured from the panel in real sun. Heat, haze, sun angle and the device being charged all cut output, so 70-85% of the rated watts is a normal real-world result.
| Tested by | Measured peak | Of rated | Conditions |
|---|---|---|---|
| The Gadgeteer | 385 W | 96% | December in Michigan on a semi-sunny day; 329 W on a fairly cloudy day. The review does not say what displayed the reading. |
Specifications
| Output | |
|---|---|
| Rated power | 400 W |
| Tested output | 385 W (96%) |
| Efficiency | 22% (solar conversion rate per ALLPOWERS' spec table (cell or module not stated); the manual gives 19-23%) |
| Cells | Polycrystalline |
| Bifacial | No |
| Electrical | |
| Open-circuit voltage (Voc) | 45.3 V |
| Voltage at max power (Vmp) | 37.4 V |
| Short-circuit current (Isc) | 11.4 A |
| Current at max power (Imp) | 10.6 A |
| Connections | |
| Output connector | MC4 |
| Cables included | MC4 to XT60, MC4 to DC5525 + DC8020 adapter |
| Build | |
| Weight | 40.8 lb (18.5 kg) |
| Folded size | 41.26 x 20.94 x 2.56 in |
| Unfolded size | 41.26 x 104.72 x 0.2 in |
| Folding sections | 5 |
| Kickstand | Yes |
| Water resistance | IP67 |
| Warranty | 2 years |
Alternatives in this size
Renogy 400W N-Type Portable Solar Panel Blanket
#5 in LargeFull review
For van, truck and SUV campers who want 400 W from something that stows like a backpack. Owners of small power stations should check the voltage limit, and anyone who wants to prop a panel up on legs should look at a folding suitcase panel instead.
Amazon $469.99 Renogy $469.99$469.99
CTOLITY 400W Portable Solar Panel (400W-NEW)
#7 in LargeFull review
A low-priced 400 W folding panel, but its listing is too thin and inconsistent to recommend over better-documented panels until CTOLITY publishes full specs.
Amazon $289.99$289.99
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