--- title: "Heckert Solar ZEUS 2.1-640 vs Heckert Solar ZEUS 2.1 640W - Solar Panel Comparison | ComparePV" description: "Compare Heckert Solar ZEUS 2.1-640 vs Heckert Solar ZEUS 2.1 640W side by side: what actually differs, output when it is hot, thirty-year production, and the full specification." source: "https://comparepv.com/compare/heckert-solar-zeus-2-1-640/heckert-solar-zeus-2-1-640w" updated: 2026-09-12 --- # Heckert Solar ZEUS 2.1-640 vs Heckert Solar ZEUS 2.1 640W One difference, none of them an advantage The largest is cell technology: N-type vs TOPCon. 18 of 19 comparable parameters are identical. ## The two panels | Attribute | A | B | | --- | --- | --- | | Panel | [Heckert Solar ZEUS 2.1-640](https://comparepv.com/panel/heckert-solar-zeus-2-1-640) | [Heckert Solar ZEUS 2.1 640W](https://comparepv.com/panel/heckert-solar-zeus-2-1-640w) | | Manufacturer | Heckert Solar | Heckert Solar | | Power | 640 Wp | 640 Wp | | Efficiency | 23.70 % | 23.70 % | | Technology | N-type | TOPCon | ## Where they differ Ranked by how much the difference matters, not by datasheet order. | Parameter | 1-640 | 1 640W | Difference | | --- | --- | --- | --- | | Cell technology | N-type | TOPCon | N-type vs TOPCon | ## Every compared parameter | Parameter | 1-640 | 1 640W | | --- | --- | --- | | Rated power | 640 Wp | 640 Wp | | Module efficiency | 23.70 % | 23.70 % | | Power density | 236.9 Wp/m² | 236.9 Wp/m² | | Open-circuit voltage | 49.75 V | 49.75 V | | Voltage at max power | 41.38 V | 41.38 V | | Short-circuit current | 16.33 A | 16.33 A | | Current at max power | 15.47 A | 15.47 A | | Temperature coefficient | -0.280 %/°C | -0.280 %/°C | | Dimensions | 2382x1134x30 mm | 2382x1134x30 mm | | Module area | 2.701 m² | 2.701 m² | | Weight | 32.5 kg | 32.5 kg | | Weight per kWp | 50.8 kg/kWp | 50.8 kg/kWp | | Product warranty | 12 yrs | 12 yrs | | Performance warranty | 30 yrs | 30 yrs | | Annual degradation | 0.45 %/yr | 0.45 %/yr | | Cell technology | N-type | TOPCon | | Cell type | Monocrystalline | Monocrystalline | | Cell count | 132 | 132 | | Bifacial | Yes | Yes | ## Thirty-year yield Each panel's own declared degradation curve, at 1,200 kWh/kWp a year Same temp coeff. for both panels (-0.280 %/°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, 1-640:** 21,076 kWh - **Cumulative output, 1 640W:** 21,076 kWh - **Gap:** No difference ## Output when hot | Condition | Cell temperature | 1-640 | 1 640W | Retained | | --- | --- | --- | --- | --- | | Standard test conditions | 25 °C | 640 W | 640 W | 100.0% of rated power | | Cool, bright day | 40 °C | 613 W | 613 W | 95.8% of rated power | | Typical summer roof | 55 °C | 586 W | 586 W | 91.6% of rated power | | Hot roof | 70 °C | 559 W | 559 W | 87.4% of rated power | ## Against the whole database | Measure | 1-640 | 1 640W | Out of | Note | | --- | --- | --- | --- | --- | | Efficiency | #511 | #511 | 13,953 | Tied - the same position in the database | | Power density | #515 | #515 | 13,953 | Tied - the same position in the database | | Heat behaviour | #1,290 | #1,290 | 13,953 | Tied - the same position in the database | | Weight | #4,174 | #4,174 | 13,953 | Tied - the same position in the database | | Warranty | #21 | #21 | 13,953 | Tied - the same position in the database | | Overall | #1,515 | #1,515 | 13,953 | Tied - the same position in the database | ## Questions ### Which panel is better: Heckert Solar ZEUS 2.1-640 or Heckert Solar ZEUS 2.1 640W? According to our database: both panels are closely matched on key specs - the decision often comes down to price and local availability. See the full spec comparison and 30-year energy simulation above for a complete picture. ### What is the efficiency of Heckert Solar ZEUS 2.1-640 and Heckert Solar ZEUS 2.1 640W? **Heckert Solar ZEUS 2.1-640** has a module efficiency of **23.70%**, while **Heckert Solar ZEUS 2.1 **640 W**** is **23.70%**. Higher efficiency means more electricity from the same roof area - useful when space is limited. ### What cell technology does Heckert Solar ZEUS 2.1-640 use vs Heckert Solar ZEUS 2.1 640W? **Heckert Solar ZEUS 2.1-640** uses **N-type** cells; **Heckert Solar ZEUS 2.1 **640 W**** 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 Heckert Solar ZEUS 2.1-640 and Heckert Solar ZEUS 2.1 640W? **Heckert Solar ZEUS 2.1-640** has a **30 years** power warranty; **Heckert Solar ZEUS 2.1 **640 W**** 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 Heckert Solar ZEUS 2.1-640 and Heckert Solar ZEUS 2.1 640W bifacial panels? Both **Heckert Solar ZEUS 2.1-640** and **Heckert Solar ZEUS 2.1 **640 W**** are bifacial - they capture reflected light from the ground, which can add 5**-15%** more annual energy on ground-mount or elevated rooftop installations with a light surface beneath. ## Related comparisons - [Heckert Solar ZEUS 2.1-640 vs Heckert Solar ZEUS 2.1-635](https://comparepv.com/compare/heckert-solar-zeus-2-1-640/heckert-solar-zeus-2-1-635) - One difference: module efficiency - [Heckert Solar ZEUS 2.1-640 vs Heckert Solar ZEUS 2.1 635W](https://comparepv.com/compare/heckert-solar-zeus-2-1-640/heckert-solar-zeus-2-1-635w) - 2 differences, the largest is cell technology - [Heckert Solar ZEUS 2.1-640 vs Heckert Solar ZEUS 1.2 FullBlack 280W](https://comparepv.com/compare/heckert-solar-zeus-2-1-640/heckert-solar-zeus-1-2-fullblack-280w) - 14 differences, the largest is rated power - [Heckert Solar ZEUS 2.1-640 vs Heckert Solar ZEUS 1.2-280](https://comparepv.com/compare/heckert-solar-zeus-2-1-640/heckert-solar-zeus-1-2-280) - 14 differences, the largest is rated power - [Heckert Solar ZEUS 2.1-640 vs Heckert Solar ZEUS 1.2 FullBlack 275W](https://comparepv.com/compare/heckert-solar-zeus-2-1-640/heckert-solar-zeus-1-2-fullblack-275w) - 14 differences, the largest is module efficiency - [Heckert Solar ZEUS 2.1-640 vs Heckert Solar ZEUS 1.2-275](https://comparepv.com/compare/heckert-solar-zeus-2-1-640/heckert-solar-zeus-1-2-275) - 14 differences, the largest is module efficiency --- Source: https://comparepv.com/compare/heckert-solar-zeus-2-1-640/heckert-solar-zeus-2-1-640w 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.