The Renogy 800W (2 x 400W) Bifacial 2-Pack and the Renogy 640W (2 x 320W) Bifacial 2-Pack are evenly matched, rated 3.9 and 3.9. The Renogy 800W (2 x 400W) Bifacial 2-Pack leads on efficiency. The Renogy 640W (2 x 320W) Bifacial 2-Pack costs $172.65 less ($487.34 vs $659.99).
A pair of large Renogy bifacial panels for a home rooftop, shed or ground-mount array with an MPPT controller, for buyers who value the 10-year warranty over the lowest price per watt.
Amazon $699.99 Renogy $659.99A low-cost bifacial pair for a ground mount or shed roof over light gravel or concrete, where the back side can earn its keep. On a dark roof, Renogy’s N-type 320 W pair is the better panel.
Amazon $487.34Prices were last checked October 26, 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 800W (2 x 400W) Bifacial 2-Pack | Renogy 640W (2 x 320W) Bifacial 2-Pack |
|---|---|---|
| Overall rating | 3.9/5 | 3.9/5 |
| Value 45% | 64 $0.82 per rated watt | 70 $0.76 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% | 50 20.5% module efficiency (from size and rated power) | 24 19.2% module efficiency |
| Renogy 800W (2 x 400W) Bifacial 2-Pack | Renogy 640W (2 x 320W) Bifacial 2-Pack | |
|---|---|---|
| Output | ||
| Rated power | 800 W | 640 W |
| Module efficiency | 20.5% (rated power over panel area) | 19.2% |
| Claimed efficiency | 25% (cell efficiency, "up to"; datasheet module efficiency 21.5%) | 19.2% (module efficiency from the datasheet; no cell efficiency published) |
| Cells | Monocrystalline (N-type, 16BB, half-cut, 108 cells) | Monocrystalline (PERC, 10BB, half-cut, 90 cells (per the Amazon listing and datasheet)) |
| Bifacial | Yes | Yes |
| Electrical | ||
| Open-circuit voltage (Voc) | 39.4 V | 30.4 V |
| Voltage at max power (Vmp) | 34 V | 26.1 V |
| Short-circuit current (Isc) | 13.1 A | 13.1 A |
| Current at max power (Imp) | 11.8 A | 12.3 A |
| Voc temperature coefficient | -0.3%/°C | -0.3%/°C |
| Series / parallel | Yes | Yes |
| Connections | ||
| Output connector | MC4 | Solar connectors (IP68) |
| Build | ||
| Dimensions | 67.8 x 44.7 x 1.4 in (each panel) | 67.9 x 38.0 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 | 25-year power output warranty | 25-year power output warranty |
| Released | 2026-07 | 2025-07 |
