--- title: "Solaria PowerXT 420R-PL vs Solaria SPV660-TG12-132BD - Solar Panel Comparison | ComparePV" description: "Compare Solaria PowerXT 420R-PL vs Solaria SPV660-TG12-132BD side by side: what actually differs, output when it is hot, thirty-year production, and the full specification." source: "https://comparepv.com/compare/solaria-powerxt-420r-pl/solaria-spv660-tg12-132bd" updated: 2026-09-11 --- # Solaria PowerXT 420R-PL vs Solaria SPV660-TG12-132BD SPV660-TG12-132BD leads on the differences that matter The largest is module efficiency: 1.38 pp more efficient. 4 of 16 comparable parameters are identical, with 3 more left out because at least one datasheet does not publish them. ## The two panels | Attribute | A | B | | --- | --- | --- | | Panel | [Solaria PowerXT 420R-PL](https://comparepv.com/panel/solaria-powerxt-420r-pl) | [Solaria SPV660-TG12-132BD](https://comparepv.com/panel/solaria-spv660-tg12-132bd) | | Manufacturer | Solaria | Solaria | | Power | 420 Wp | 660 Wp | | Efficiency | 19.90 % | 21.28 % | | Technology | | TOPCon | ## Where they differ Ranked by how much the difference matters, not by datasheet order. | Parameter | PowerXT 420R-PL | SPV660-TG12-132BD | Difference | | --- | --- | --- | --- | | Module efficiency | 19.90 % | 21.28 % | +1.38 pp for SPV660-TG12-132BD | | Temperature coefficient | -0.390 %/°C | -0.300 %/°C | +0.090 %/°C for SPV660-TG12-132BD | | Rated power | 420 Wp | 660 Wp | +240 W for SPV660-TG12-132BD | | Power density | 198.9 Wp/m² | 212.7 Wp/m² | +13.8 Wp/m² for SPV660-TG12-132BD | | Weight | 21.7 kg | 38.0 kg | -16.3 kg for PowerXT 420R-PL | | Product warranty | 30 yrs | 12 yrs | +18 yrs for PowerXT 420R-PL | | Weight per kWp | 51.7 kg/kWp | 57.6 kg/kWp | -5.9 kg/kWp for PowerXT 420R-PL | | Short-circuit current | 11.60 A | 17.84 A | 6.24 A apart | | Module area | 2.112 m² | 3.103 m² | 0.991 m² apart | | Current at max power | 11.09 A | 17.01 A | 5.92 A apart | | Bifacial | No | Yes | No vs Yes | | Dimensions | 1957x1079x35 mm | 2383x1302x30 mm | 1957x1079x35 mm vs 2383x1302x30 mm | ## Every compared parameter | Parameter | PowerXT 420R-PL | SPV660-TG12-132BD | | --- | --- | --- | | Rated power | 420 Wp | 660 Wp | | Module efficiency | 19.90 % | 21.28 % | | Power density | 198.9 Wp/m² | 212.7 Wp/m² | | Open-circuit voltage | 45.70 V | 46.10 V | | Voltage at max power | 37.90 V | 38.81 V | | Short-circuit current | 11.60 A | 17.84 A | | Current at max power | 11.09 A | 17.01 A | | Temperature coefficient | -0.390 %/°C | -0.300 %/°C | | Dimensions | 1957x1079x35 mm | 2383x1302x30 mm | | Module area | 2.112 m² | 3.103 m² | | Weight | 21.7 kg | 38.0 kg | | Weight per kWp | 51.7 kg/kWp | 57.6 kg/kWp | | Product warranty | 30 yrs | 12 yrs | | Performance warranty | 30 yrs | 30 yrs | | Annual degradation | 0.48 %/yr | - | | Cell technology | - | TOPCon | | Cell type | Monocrystalline | Monocrystalline | | Cell count | - | 132 | | Bifacial | No | Yes | ## Thirty-year yield Declared first-year losses, with 0.40% a year afterwards assumed for both panels, at 1,200 kWh/kWp a year - **Cumulative output, PowerXT 420R-PL:** 13,941 kWh - **Cumulative output, SPV660-TG12-132BD:** 21,907 kWh - **Gap:** 7,966 kWh ## Output when hot | Condition | Cell temperature | PowerXT 420R-PL | SPV660-TG12-132BD | Retained | | --- | --- | --- | --- | --- | | Standard test conditions | 25 °C | 420 W | 660 W | 100.0% of rated power | | Cool, bright day | 40 °C | 395 W | 630 W | 94.2% of rated power | | Typical summer roof | 55 °C | 371 W | 601 W | 88.3% of rated power | | Hot roof | 70 °C | 346 W | 571 W | 82.5% of rated power | ## Against the whole database | Measure | PowerXT 420R-PL | SPV660-TG12-132BD | Out of | Note | | --- | --- | --- | --- | --- | | Efficiency | #12,331 | #8,795 | 14,005 | SPV660-TG12-132BD leads by 3,536 places | | Power density | #12,344 | #8,718 | 14,005 | SPV660-TG12-132BD leads by 3,626 places | | Heat behaviour | #13,579 | #6,093 | 14,005 | SPV660-TG12-132BD leads by 7,486 places | | Weight | #5,023 | #11,284 | 14,005 | PowerXT 420R-PL leads by 6,261 places | | Warranty | #21 | #21 | 14,005 | Tied - the same position in the database | | Overall | #9,324 | #3,149 | 14,005 | SPV660-TG12-132BD leads by 6,175 places | ## Questions ### Which panel is better: Solaria PowerXT 420R-PL or Solaria SPV660-TG12-132BD? According to our database: **Solaria SPV660-TG12-132BD** has higher module efficiency (**21.28%** vs **19.90%**); **Solaria SPV660-TG12-132BD** tolerates heat better (temp coeff **-0.300%/°C** vs **-0.390%/°C**). See the full spec comparison and 30-year energy simulation above for a complete picture. ### What is the efficiency of Solaria PowerXT 420R-PL and Solaria SPV660-TG12-132BD? **Solaria PowerXT 420R-PL** has a module efficiency of **19.90%**, while **Solaria SPV660-TG12-132BD** is **21.28%**. Higher efficiency means more electricity from the same roof area - useful when space is limited. ### What cell technology does Solaria PowerXT 420R-PL use vs Solaria SPV660-TG12-132BD? **Solaria PowerXT 420R-PL** uses Monocrystalline cells; **Solaria SPV660-TG12-132BD** uses **TOPCon**. 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 PowerXT 420R-PL and Solaria SPV660-TG12-132BD? **Solaria PowerXT 420R-PL** has a **30 years** power warranty; **Solaria SPV660-TG12-132BD** has a **30 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. ### Are Solaria PowerXT 420R-PL and Solaria SPV660-TG12-132BD bifacial panels? **Solaria SPV660-TG12-132BD** is bifacial (captures light from both faces); **Solaria PowerXT 420R-PL** is monofacial. Bifacial panels work best on ground mounts or raised structures with a light-coloured surface underneath. ## Related comparisons - [Solaria PowerXT 420R-PL vs Solaria PowerXT 430R-PL](https://comparepv.com/compare/solaria-powerxt-420r-pl/solaria-powerxt-430r-pl) - 3 differences, the largest is module efficiency - [Solaria PowerXT 420R-PL vs Solaria Solaria PowerXT-430C-PD](https://comparepv.com/compare/solaria-powerxt-420r-pl/solaria-solaria-powerxt-430c-pd) - 9 differences, the largest is performance warranty - [Solaria PowerXT 420R-PL vs Solaria Solaria PowerXT-420C-BD](https://comparepv.com/compare/solaria-powerxt-420r-pl/solaria-solaria-powerxt-420c-bd) - 10 differences, the largest is performance warranty - [Solaria PowerXT 420R-PL vs Solaria Solaria PowerXT-420C-PD](https://comparepv.com/compare/solaria-powerxt-420r-pl/solaria-solaria-powerxt-420c-pd) - 9 differences, the largest is performance warranty - [Solaria PowerXT 420R-PL vs Solaria Solaria PowerXT-410C-BD](https://comparepv.com/compare/solaria-powerxt-420r-pl/solaria-solaria-powerxt-410c-bd) - 10 differences, the largest is module efficiency - [Solaria PowerXT 420R-PL vs Solaria Solaria PowerX-400R](https://comparepv.com/compare/solaria-powerxt-420r-pl/solaria-solaria-powerx-400r) - 13 differences, the largest is performance warranty --- Source: https://comparepv.com/compare/solaria-powerxt-420r-pl/solaria-spv660-tg12-132bd 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.