The Renogy 640W (2 x 320W) N-Type 18BB Rigid Solar Panel 2-Pack is the better rigid solar panel overall, rated 4.0 to 3.7. The Renogy 640W (2 x 320W) N-Type 18BB Rigid Solar Panel 2-Pack leads on efficiency. The Renogy 640W (2 x 320W) N-Type 18BB Rigid Solar Panel 2-Pack costs $289.01 less ($599.99 vs $889).
A 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 $599.99A pair of large N-type bifacial panels for a small home backup, shed or ground-mount system with an MPPT controller. Bigger arrays are cheaper per watt in SUNGOLDPOWER’s larger packs.
Amazon $889 SUNGOLDPOWER $889Prices 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 | Renogy 640W (2 x 320W) N-Type 18BB Rigid Solar Panel 2-Pack | SUNGOLDPOWER 900W (2 x 450W) N-Type 16BB Bifacial Rigid Solar Panel 2-Pack (SGN-450-BDG5, UL 61730) |
|---|---|---|
| Overall rating | 4.0/5 | 3.7/5 |
| Value 45% | 54 $0.94 per rated watt | 49 $0.99 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, 12-year warranty |
| Efficiency 15% | 100 25% claimed efficiency | 58 22.5% claimed efficiency |
| Renogy 640W (2 x 320W) N-Type 18BB Rigid Solar Panel 2-Pack | SUNGOLDPOWER 900W (2 x 450W) N-Type 16BB Bifacial Rigid Solar Panel 2-Pack (SGN-450-BDG5, UL 61730) | |
|---|---|---|
| Output | ||
| Rated power | 640 W | 900 W |
| Efficiency | 25% (cell efficiency, "up to"; datasheet module efficiency 22.2%) | 22.5% (module efficiency) |
| Cells | Monocrystalline (N-type, 18BB (per Renogy's product page and Amazon; the datasheet says only monocrystalline, 60 cells)) | Monocrystalline (N-type, 16BB, 96 cells (182 x 210 mm)) |
| Bifacial | No | Yes |
| Electrical | ||
| Open-circuit voltage (Voc) | 43.8 V | 35 V |
| Voltage at max power (Vmp) | 37.9 V | 30.1 V |
| Short-circuit current (Isc) | 8.9 A | 16.1 A |
| Current at max power (Imp) | 8.5 A | 15 A |
| Voc temperature coefficient | -0.3%/°C | -0.3%/°C |
| Connections | ||
| Output connector | Solar connectors (IP68) | MC4 |
| Build | ||
| Weight | - | 53.4 lb (24.2 kg) |
| Dimensions | 64.6 x 34.7 x 1.4 in (each panel) | 69.37 x 44.65 x 1.38 in (each panel) |
| Frame | anodized aluminum alloy | black anodized aluminum alloy |
| Glass | 3.2 mm tempered | 2.0 mm anti-reflective front, 2.0 mm heat-strengthened back (dual glass) |
| Junction box rating | IP68 | IP68 |
| Warranty | 10 years | 12 years |
| Output warranty | 95% output for 5 years, 90% for 10 years, 80% for 25 years | 30-year linear power warranty, 87.4% output at 30 years, 0.40% annual degradation |
