The Callsun 400W (2 x 200W) N-Type Bifacial Rigid Solar Panel 2-Pack is the better rigid solar panel overall, rated 4.2 to 3.8. The DOKIO 400W 31V Monocrystalline Rigid Solar Panel wins on value. The DOKIO 400W 31V Monocrystalline Rigid Solar Panel costs $65.22 less ($254.77 vs $319.99).
A strong value for a 400 W ground mount, shed roof or large RV roof, and a good match for power stations with a 60 V solar input. Mostly sold as a pair on Amazon.
Amazon $319.99 Callsun $319.99A low-cost large panel for a shed, greenhouse or ground mount with an MPPT controller. Buyers who want a stated warranty and full spec sheet should pay a little more for a better-documented brand.
Amazon $254.77Prices 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.
Each factor is scored 0-100 against the same fixed reference points for every 150 w and up rigid solar panel; a clear win is highlighted. How we rank explains each one.
| Factor weight | Callsun 400W (2 x 200W) N-Type Bifacial Rigid Solar Panel 2-Pack | DOKIO 400W 31V Monocrystalline Rigid Solar Panel |
|---|---|---|
| Overall rating | 4.2/5 | 3.8/5 |
| Value 45% | 67 $0.80 per rated watt | 82 $0.64 per rated watt |
| Tested output 15% | 50 not yet independently tested (neutral score used) | 50 not yet independently tested (neutral score used) |
| Durability 25% | 100 IP68, 10-year warranty | 50 IP rating and warranty not published (neutral score used) |
| Efficiency 15% | 100 25% claimed efficiency | 50 efficiency not published (neutral score used) |
| Callsun 400W (2 x 200W) N-Type Bifacial Rigid Solar Panel 2-Pack | DOKIO 400W 31V Monocrystalline Rigid Solar Panel | |
|---|---|---|
| Output | ||
| Rated power | 400 W | 400 W |
| Efficiency | 25% (cell efficiency) | - |
| Cells | Monocrystalline (N-type, 16BB, split into two parallel halves for shade tolerance) | Monocrystalline |
| Bifacial | Yes | No |
| Electrical | ||
| Open-circuit voltage (Voc) | 27.3 V | 37.1 V |
| Voltage at max power (Vmp) | 23.7 V | 31 V |
| Short-circuit current (Isc) | 8.9 A | 13.2 A |
| Current at max power (Imp) | 8.4 A | - |
| Series / parallel | Yes | Yes |
| Connections | ||
| Output connector | MC4-compatible solar connectors | MC4 |
| Build | ||
| Weight | 47.6 lb (21.6 kg) | 49.4 lb (22.4 kg) |
| Dimensions | 51.34 x 30.31 x 1.58 in (each panel) | 67.8 x 44.6 x 1.2 in |
| Frame | anodized aluminum alloy | aluminum |
| Glass | 3.2 mm tempered | tempered |
| Junction box rating | IP68 | - |
| Warranty | 10 years | - |
| Output warranty | 84.5% output after 25 years | - |
