The Callsun 420W (2 x 210W) Bifacial 2-Pack and the JJN 425W Bifacial (JJN-SP-425W-N) are evenly matched, rated 4.0 and 4.0. The Callsun 420W (2 x 210W) Bifacial 2-Pack leads on durability. The JJN 425W Bifacial (JJN-SP-425W-N) wins on efficiency. The JJN 425W Bifacial (JJN-SP-425W-N) costs $19.98 less ($279.99 vs $299.97).
A good-value pair for a 24 V RV, van or cabin system with an MPPT controller, or for a power station wired in parallel. Owners of 12 V PWM setups should pick a lower-voltage panel.
Amazon $299.97A low-cost large-format panel for a home rooftop, shed or ground-mount array on a 24 V or 48 V system with an MPPT controller. Too big and too high-voltage for most RV and van setups.
Amazon $279.99Prices 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 | Callsun 420W (2 x 210W) Bifacial 2-Pack | JJN 425W Bifacial (JJN-SP-425W-N) |
|---|---|---|
| Overall rating | 4.0/5 | 4.0/5 |
| Value 45% | 75 $0.71 per rated watt | 80 $0.66 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 | 67 IP68, 5-year warranty |
| Efficiency 15% | 38 19.9% module efficiency (from size and rated power) | 74 21.7% module efficiency (from size and rated power) |
| Callsun 420W (2 x 210W) Bifacial 2-Pack | JJN 425W Bifacial (JJN-SP-425W-N) | |
|---|---|---|
| Output | ||
| Rated power | 420 W | 425 W |
| Module efficiency | 19.9% (rated power over panel area) | 21.7% (rated power over panel area) |
| Claimed efficiency | 25.6% (cell efficiency; no module efficiency published) | 25% (published as "25+%"; the maker does not say whether this is cell or module efficiency) |
| Cells | Monocrystalline (N-type, 16BB, quarter-cut cells, wired as two parallel halves for shade tolerance) | Monocrystalline (N-type, 16BB, 182 mm full cells, Grade A+) |
| Bifacial | Yes | Yes |
| Electrical | ||
| Open-circuit voltage (Voc) | 40.3 V | 38.6 V |
| Voltage at max power (Vmp) | 34.2 V | 32.1 V |
| Short-circuit current (Isc) | 6.5 A | 13.8 A |
| Current at max power (Imp) | 6.1 A | 13.2 A |
| Voc temperature coefficient | -0.2%/°C | - |
| Series / parallel | Yes | - |
| Connections | ||
| Output connector | Solar connectors | MC4 |
| Build | ||
| Weight | - | 53.6 lb (24.3 kg) |
| Dimensions | 54.2 x 30.2 x 1.4 in (each panel) | 67.8 x 44.7 x 1.2 in |
| Frame | anodized aluminum alloy | anodized aluminum |
| Glass | 3.2 mm tempered | tempered, dual-glass construction |
| Junction box rating | IP68 | IP68 |
| Warranty | 10 years | 5 years |
| Output warranty | 84.5% output after 25 years | 30-year performance warranty, 87.4% output |
| Released | 2026-08 | 2026-02 |
