--- title: "Solaria Solaria PowerX-390R vs Solaria Solaria PowerX-400R - Solar Panel Comparison | ComparePV" description: "Compare Solaria Solaria PowerX-390R vs Solaria Solaria PowerX-400R side by side: what actually differs, output when it is hot, thirty-year production, and the full specification." source: "https://comparepv.com/compare/solaria-solaria-powerx-390r/solaria-solaria-powerx-400r" updated: 2026-09-11 --- # Solaria Solaria PowerX-390R vs Solaria Solaria PowerX-400R 400R leads on the differences that matter The largest is module efficiency: 0.50 pp more efficient. 14 of 17 comparable parameters are identical, with 2 more left out because at least one datasheet does not publish them. ## The two panels | Attribute | A | B | | --- | --- | --- | | Panel | [Solaria Solaria PowerX-390R](https://comparepv.com/panel/solaria-solaria-powerx-390r) | [Solaria Solaria PowerX-400R](https://comparepv.com/panel/solaria-solaria-powerx-400r) | | Manufacturer | Solaria | Solaria | | Power | 390 Wp | 400 Wp | | Efficiency | 20.00 % | 20.50 % | | Technology | | | ## Where they differ Ranked by how much the difference matters, not by datasheet order. | Parameter | 390R | 400R | Difference | | --- | --- | --- | --- | | Module efficiency | 20.00 % | 20.50 % | +0.50 pp for 400R | | Power density | 199.6 Wp/m² | 204.7 Wp/m² | +5.1 Wp/m² for 400R | | Rated power | 390 Wp | 400 Wp | +10 W for 400R | ## Every compared parameter | Parameter | 390R | 400R | | --- | --- | --- | | Rated power | 390 Wp | 400 Wp | | Module efficiency | 20.00 % | 20.50 % | | Power density | 199.6 Wp/m² | 204.7 Wp/m² | | Open-circuit voltage | 36.90 V | 37.30 V | | Voltage at max power | 30.60 V | 31.00 V | | Short-circuit current | 13.52 A | 13.68 A | | Current at max power | 12.73 A | 12.90 A | | Temperature coefficient | -0.360 %/°C | -0.360 %/°C | | Dimensions | 1723x1134x35 mm | 1723x1134x35 mm | | Module area | 1.954 m² | 1.954 m² | | Weight | 22.1 kg | 22.1 kg | | Weight per kWp | 56.7 kg/kWp | 55.2 kg/kWp | | Product warranty | 25 yrs | 25 yrs | | Performance warranty | 25 yrs | 25 yrs | | Annual degradation | 0.50 %/yr | 0.50 %/yr | | Cell technology | - | - | | Cell type | Monocrystalline | Monocrystalline | | Cell count | - | - | | Bifacial | No | No | ## Thirty-year yield Each panel's own declared degradation curve, at 1,200 kWh/kWp a year Same temp coeff. for both panels (-0.360 %/°C), so a warmer roof scales both curves by the same factor: the totals fall together and neither panel gains on the other. - **Cumulative output, 390R:** 12,741 kWh - **Cumulative output, 400R:** 13,068 kWh - **Gap:** 327 kWh ## Output when hot | Condition | Cell temperature | 390R | 400R | Retained | | --- | --- | --- | --- | --- | | Standard test conditions | 25 °C | 390 W | 400 W | 100.0% of rated power | | Cool, bright day | 40 °C | 369 W | 378 W | 94.6% of rated power | | Typical summer roof | 55 °C | 348 W | 357 W | 89.2% of rated power | | Hot roof | 70 °C | 327 W | 335 W | 83.8% of rated power | ## Against the whole database | Measure | 390R | 400R | Out of | Note | | --- | --- | --- | --- | --- | | Efficiency | #12,214 | #11,308 | 14,005 | 400R leads by 906 places | | Power density | #12,284 | #11,499 | 14,005 | 400R leads by 785 places | | Heat behaviour | #12,345 | #12,345 | 14,005 | Tied - the same position in the database | | Weight | #10,801 | #9,691 | 14,005 | 400R leads by 1,110 places | | Warranty | #9,798 | #9,798 | 14,005 | Tied - the same position in the database | | Overall | #11,244 | #10,732 | 14,005 | 400R leads by 512 places | ## Questions ### Which panel is better: Solaria Solaria PowerX-390R or Solaria Solaria PowerX-400R? According to our database: **Solaria **Solaria** PowerX-400R** has higher module efficiency (**20.50%** vs **20.00%**). See the full spec comparison and 30-year energy simulation above for a complete picture. ### What is the efficiency of Solaria Solaria PowerX-390R and Solaria Solaria PowerX-400R? **Solaria **Solaria** PowerX-390R** has a module efficiency of **20.00%**, while **Solaria **Solaria** PowerX-400R** is **20.50%**. Higher efficiency means more electricity from the same roof area - useful when space is limited. ### What cell technology does Solaria Solaria PowerX-390R use vs Solaria Solaria PowerX-400R? **Solaria **Solaria** PowerX-390R** uses Monocrystalline cells; **Solaria **Solaria** PowerX-400R** uses Monocrystalline. Modern **n-type** technologies (**TOPCon**, **HJT**, BC) typically deliver higher efficiency and lower degradation compared to older **PERC** (p-type) cells. ### What is the warranty on Solaria Solaria PowerX-390R and Solaria Solaria PowerX-400R? **Solaria **Solaria** PowerX-390R** has a **25 years** power warranty; **Solaria **Solaria** PowerX-400R** has a **25 years** power warranty. The power warranty guarantees a minimum percentage of rated output at the end of the warranty period (typically 80**-87%**). Product (materials) warranties are usually shorter. ## Related comparisons - [Solaria Solaria PowerX-390R vs Solaria Solaria PowerX-395R](https://comparepv.com/compare/solaria-solaria-powerx-390r/solaria-solaria-powerx-395r) - One difference: module efficiency - [Solaria Solaria PowerX-390R vs Solaria SPV680-TG12-132BD](https://comparepv.com/compare/solaria-solaria-powerx-390r/solaria-spv680-tg12-132bd) - 14 differences, the largest is module efficiency - [Solaria Solaria PowerX-390R vs Solaria SPV675-TG12-132BD](https://comparepv.com/compare/solaria-solaria-powerx-390r/solaria-spv675-tg12-132bd) - 14 differences, the largest is module efficiency - [Solaria Solaria PowerX-390R vs Solaria SPV670-TG12-132BD](https://comparepv.com/compare/solaria-solaria-powerx-390r/solaria-spv670-tg12-132bd) - 14 differences, the largest is module efficiency - [Solaria Solaria PowerX-390R vs Solaria SPV665-TG12-132BD](https://comparepv.com/compare/solaria-solaria-powerx-390r/solaria-spv665-tg12-132bd) - 14 differences, the largest is module efficiency - [Solaria Solaria PowerX-390R vs Solaria SPV660-TG12-132BD](https://comparepv.com/compare/solaria-solaria-powerx-390r/solaria-spv660-tg12-132bd) - 14 differences, the largest is module efficiency --- Source: https://comparepv.com/compare/solaria-solaria-powerx-390r/solaria-solaria-powerx-400r Not in this file, on the page: the thirty-year yield curve year by year at a cell temperature you pick and a written summary generated on request.