--- title: "DAH Solar DHN-78X16/DG-635W vs DAH Solar DHN-78X16/DG-640W - Solar Panel Comparison | ComparePV" description: "Compare DAH Solar DHN-78X16/DG-635W vs DAH Solar DHN-78X16/DG-640W side by side: what actually differs, output when it is hot, thirty-year production, and the full specification." source: "https://comparepv.com/compare/dah-dhn-78x16-dg-635w/dah-dhn-78x16-dg-640w" updated: 2026-09-11 --- # DAH Solar DHN-78X16/DG-635W vs DAH Solar DHN-78X16/DG-640W Identical on every published parameter All 18 comparable parameters agree, with 1 more left out because at least one datasheet does not publish it. Two records this alike are usually one panel sold under two names, or two bins of the same production line - decide on price and on who you would rather buy from. ## The two panels | Attribute | A | B | | --- | --- | --- | | Panel | [DAH Solar DHN-78X16/DG-635W](https://comparepv.com/panel/dah-dhn-78x16-dg-635w) | [DAH Solar DHN-78X16/DG-640W](https://comparepv.com/panel/dah-dhn-78x16-dg-640w) | | Manufacturer | DAH Solar | DAH Solar | | Power | 635 Wp | 640 Wp | | Efficiency | 22.72 % | 22.90 % | | Technology | TOPCon | TOPCon | ## Every compared parameter | Parameter | 635W | 640W | | --- | --- | --- | | Rated power | 635 Wp | 640 Wp | | Module efficiency | 22.72 % | 22.90 % | | Power density | 227.2 Wp/m² | 229.0 Wp/m² | | Open-circuit voltage | 56.20 V | 56.40 V | | Voltage at max power | 47.40 V | 47.60 V | | Short-circuit current | 14.26 A | 14.32 A | | Current at max power | 13.40 A | 13.45 A | | Temperature coefficient | -0.290 %/°C | -0.290 %/°C | | Dimensions | 2465x1134x34 mm | 2465x1134x34 mm | | Module area | 2.795 m² | 2.795 m² | | Weight | 34.2 kg | 34.2 kg | | Weight per kWp | 53.9 kg/kWp | 53.4 kg/kWp | | Product warranty | 15 yrs | 15 yrs | | Performance warranty | 30 yrs | 30 yrs | | Annual degradation | - | - | | Cell technology | TOPCon | TOPCon | | Cell type | Monocrystalline | Monocrystalline | | Cell count | 156 | 156 | | Bifacial | Yes | Yes | ## Thirty-year yield A 1.0% first-year loss then 0.40% a year, assumed for both panels, at 1,200 kWh/kWp a year Same temp coeff. for both panels (-0.290 %/°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, 635W:** 21,306 kWh - **Cumulative output, 640W:** 21,473 kWh - **Gap:** 167 kWh ## Output when hot | Condition | Cell temperature | 635W | 640W | Retained | | --- | --- | --- | --- | --- | | Standard test conditions | 25 °C | 635 W | 640 W | 100.0% of rated power | | Cool, bright day | 40 °C | 607 W | 612 W | 95.7% of rated power | | Typical summer roof | 55 °C | 580 W | 584 W | 91.3% of rated power | | Hot roof | 70 °C | 552 W | 556 W | 87.0% of rated power | ## Against the whole database | Measure | 635W | 640W | Out of | Note | | --- | --- | --- | --- | --- | | Efficiency | #3,245 | #2,359 | 14,005 | 640W leads by 886 places | | Power density | #3,252 | #2,389 | 14,005 | 640W leads by 863 places | | Heat behaviour | #2,165 | #2,165 | 14,005 | Tied - the same position in the database | | Weight | #8,005 | #7,363 | 14,005 | 640W leads by 642 places | | Warranty | #21 | #21 | 14,005 | Tied - the same position in the database | | Overall | #1,909 | #1,704 | 14,005 | 640W leads by 205 places | ## Questions ### Which panel is better: DAH Solar DHN-78X16/DG-635W or DAH Solar DHN-78X16/DG-640W? According to our database: **DAH Solar DHN-78X16/DG-**640 W**** has higher module efficiency (**22.90%** vs **22.72%**). See the full spec comparison and 30-year energy simulation above for a complete picture. ### What is the efficiency of DAH Solar DHN-78X16/DG-635W and DAH Solar DHN-78X16/DG-640W? **DAH Solar DHN-78X16/DG-**635 W**** has a module efficiency of **22.72%**, while **DAH Solar DHN-78X16/DG-**640 W**** is **22.90%**. Higher efficiency means more electricity from the same roof area - useful when space is limited. ### What cell technology does DAH Solar DHN-78X16/DG-635W use vs DAH Solar DHN-78X16/DG-640W? **DAH Solar DHN-78X16/DG-**635 W**** uses **TOPCon** cells; **DAH Solar DHN-78X16/DG-**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 DAH Solar DHN-78X16/DG-635W and DAH Solar DHN-78X16/DG-640W? **DAH Solar DHN-78X16/DG-**635 W**** has a **30 years** power warranty; **DAH Solar DHN-78X16/DG-**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 DAH Solar DHN-78X16/DG-635W and DAH Solar DHN-78X16/DG-640W bifacial panels? Both **DAH Solar DHN-78X16/DG-**635 W**** and **DAH Solar DHN-78X16/DG-**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 - [DAH Solar DHN-78X16/DG-635W vs DAH Solar DHN-78X16/DG-630W](https://comparepv.com/compare/dah-dhn-78x16-dg-635w/dah-dhn-78x16-dg-630w) - The same specification on paper - [DAH Solar DHN-78X16/DG-635W vs DAH Solar DHN-78X16/DG-625W](https://comparepv.com/compare/dah-dhn-78x16-dg-635w/dah-dhn-78x16-dg-625w) - 3 differences, the largest is module efficiency - [DAH Solar DHN-78X16/DG-635W vs DAH Solar DHN-78X16/DG-620W](https://comparepv.com/compare/dah-dhn-78x16-dg-635w/dah-dhn-78x16-dg-620w) - 3 differences, the largest is module efficiency - [DAH Solar DHN-78X16/DG-635W vs DAH Solar DHN-66Y18/DG-725](https://comparepv.com/compare/dah-dhn-78x16-dg-635w/dah-dhn-66y18-dg-725) - 12 differences, the largest is rated power - [DAH Solar DHN-78X16/DG-635W vs DAH Solar DHN-66Y18/DG-720](https://comparepv.com/compare/dah-dhn-78x16-dg-635w/dah-dhn-66y18-dg-720) - 12 differences, the largest is rated power - [DAH Solar DHN-78X16/DG-635W vs DAH Solar DHN-66Y18/DG-715](https://comparepv.com/compare/dah-dhn-78x16-dg-635w/dah-dhn-66y18-dg-715) - 12 differences, the largest is rated power --- Source: https://comparepv.com/compare/dah-dhn-78x16-dg-635w/dah-dhn-78x16-dg-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.