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 4.0. The Callsun 400W (2 x 200W) N-Type Bifacial Rigid Solar Panel 2-Pack leads on value. The Callsun 400W (2 x 200W) N-Type Bifacial Rigid Solar Panel 2-Pack costs $280 less ($319.99 vs $599.99).
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 large-panel pair for a cabin, shed or ground-mount array with a high-voltage MPPT controller. Too big and too high-voltage for most van and small RV setups.
Amazon $599.99 Renogy $599.99Prices 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 | Renogy 640W (2 x 320W) N-Type 18BB Rigid Solar Panel 2-Pack |
|---|---|---|
| Overall rating | 4.2/5 | 4.0/5 |
| Value 45% | 67 $0.80 per rated watt | 54 $0.94 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 | 100 IP68, 10-year warranty |
| Efficiency 15% | 100 25% claimed efficiency | 100 25% claimed efficiency |
| Callsun 400W (2 x 200W) N-Type Bifacial Rigid Solar Panel 2-Pack | Renogy 640W (2 x 320W) N-Type 18BB Rigid Solar Panel 2-Pack | |
|---|---|---|
| Output | ||
| Rated power | 400 W | 640 W |
| Efficiency | 25% (cell efficiency) | 25% (cell efficiency, "up to"; datasheet module efficiency 22.2%) |
| Cells | Monocrystalline (N-type, 16BB, split into two parallel halves for shade tolerance) | Monocrystalline (N-type, 18BB (per Renogy's product page and Amazon; the datasheet says only monocrystalline, 60 cells)) |
| Bifacial | Yes | No |
| Electrical | ||
| Open-circuit voltage (Voc) | 27.3 V | 43.8 V |
| Voltage at max power (Vmp) | 23.7 V | 37.9 V |
| Short-circuit current (Isc) | 8.9 A | 8.9 A |
| Current at max power (Imp) | 8.4 A | 8.5 A |
| Voc temperature coefficient | - | -0.3%/°C |
| Series / parallel | Yes | - |
| Connections | ||
| Output connector | MC4-compatible solar connectors | Solar connectors (IP68) |
| Build | ||
| Weight | 47.6 lb (21.6 kg) | - |
| Dimensions | 51.34 x 30.31 x 1.58 in (each panel) | 64.6 x 34.7 x 1.4 in (each panel) |
| Frame | anodized aluminum alloy | anodized aluminum alloy |
| Glass | 3.2 mm tempered | 3.2 mm tempered |
| Junction box rating | IP68 | IP68 |
| Warranty | 10 years | 10 years |
| Output warranty | 84.5% output after 25 years | 95% output for 5 years, 90% for 10 years, 80% for 25 years |
