TWELSEAVAN 400W Portable Solar Panel
#6 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
The TWELSEAVAN 400W Portable Solar Panel is the better portable solar panel overall, rated 4.2 to 4.1. The TWELSEAVAN 400W Portable Solar Panel leads on portability and efficiency. The ALLPOWERS SP037 400W Foldable Solar Panel wins on value and durability. The ALLPOWERS SP037 400W Foldable Solar Panel costs $100.99 less ($299 vs $399.99).
ALLPOWERS SP037 400W Foldable Solar Panel
#9 in LargeFull review
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.
Amazon $299 ALLPOWERS $299$299
Prices were last checked October 21, 2026 and are subject to change; the price and availability shown by the retailer at the time of purchase apply.
Which should you buy?
- Choose the TWELSEAVAN 400W Portable Solar Panel for portability (17.6 W per lb (22.7 lb (10.3 kg)) vs 9.8 W per lb (40.8 lb (18.5 kg))) and efficiency (24% claimed efficiency vs 22% claimed efficiency).
- Choose the ALLPOWERS SP037 400W Foldable Solar Panel for value ($0.75 per rated watt vs $1.00 per rated watt) and durability (IP67, 2-year warranty vs IP65, 2-year warranty).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every large portable solar panel; a clear win is highlighted. How we rank explains each one.
| Factor weight | TWELSEAVAN 400W Portable Solar Panel | ALLPOWERS SP037 400W Foldable Solar Panel |
|---|---|---|
| Overall rating | 4.2/5 | 4.1/5 |
| Value 30% | 86 $1.00 per rated watt | 100 $0.75 per rated watt |
| Tested output 20% | 89 not yet tested; estimated 87% of rated watts from the median of the 10 tested panels | 100 best measured 96% of rated watts (1 test) |
| Portability 15% | 97 17.6 W per lb (22.7 lb (10.3 kg)) | 32 9.8 W per lb (40.8 lb (18.5 kg)) |
| Durability 15% | 56 IP65, 2-year warranty | 80 IP67, 2-year warranty |
| Efficiency 10% | 83 24% claimed efficiency | 50 22% claimed efficiency |
| Features 10% | 35 built-in kickstand | 35 built-in kickstand |
Independent output tests
TWELSEAVAN 400W Portable Solar Panel
No independent test published yet.
ALLPOWERS SP037 400W Foldable Solar Panel
| 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
| TWELSEAVAN 400W Portable Solar Panel | ALLPOWERS SP037 400W Foldable Solar Panel | |
|---|---|---|
| Output | ||
| Rated power | 400 W | 400 W |
| Tested output | Not tested (estimated 87%) | 385 W (96%) |
| Efficiency | 24% (cell efficiency per the Amazon listing) | 22% (solar conversion rate per ALLPOWERS' spec table (cell or module not stated); the manual gives 19-23%) |
| Cells | Monocrystalline | Polycrystalline |
| Bifacial | No | No |
| Electrical | ||
| Open-circuit voltage (Voc) | 46.9 V | 45.3 V |
| Voltage at max power (Vmp) | 40 V | 37.4 V |
| Short-circuit current (Isc) | 10.6 A | 11.4 A |
| Current at max power (Imp) | 10 A | 10.6 A |
| Connections | ||
| Output connector | MC4 | MC4 |
| Cables included | 9.8 ft 5-in-1 MC4 cable (Anderson, XT60, DC8020, DC7909, DC5521), 3 DC adapters | MC4 to XT60, MC4 to DC5525 + DC8020 adapter |
| Build | ||
| Weight | 22.7 lb (10.3 kg) | 40.8 lb (18.5 kg) |
| Folded size | 26 x 35.5 in | 41.26 x 20.94 x 2.56 in |
| Unfolded size | 35.5 x 98.5 in | 41.26 x 104.72 x 0.2 in |
| Folding sections | - | 5 |
| Kickstand | Yes | Yes |
| Water resistance | IP65 | IP67 |
| Warranty | 2 years | 2 years |