--- title: "DAH Solar DHN-78X16/DG-620W vs DAH Solar DHN-78X16/DG-640W - Solar Panel Comparison | ComparePV" description: "Compare DAH Solar DHN-78X16/DG-620W 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-620w/dah-dhn-78x16-dg-640w" updated: 2026-09-11 --- # DAH Solar DHN-78X16/DG-620W vs DAH Solar DHN-78X16/DG-640W 640W leads on the differences that matter The largest is module efficiency: 0.72 pp more efficient. 15 of 18 comparable parameters are identical, with 1 more left out because at least one datasheet does not publish it. ## The two panels | Attribute | A | B | | --- | --- | --- | | Panel | [DAH Solar DHN-78X16/DG-620W](https://comparepv.com/panel/dah-dhn-78x16-dg-620w) | [DAH Solar DHN-78X16/DG-640W](https://comparepv.com/panel/dah-dhn-78x16-dg-640w) | | Manufacturer | DAH Solar | DAH Solar | | Power | 620 Wp | 640 Wp | | Efficiency | 22.18 % | 22.90 % | | Technology | TOPCon | TOPCon | ## Where they differ Ranked by how much the difference matters, not by datasheet order. | Parameter | 620W | 640W | Difference | | --- | --- | --- | --- | | Module efficiency | 22.18 % | 22.90 % | +0.72 pp for 640W | | Power density | 221.8 Wp/m² | 229.0 Wp/m² | +7.2 Wp/m² for 640W | | Rated power | 620 Wp | 640 Wp | +20 W for 640W | ## Every compared parameter | Parameter | 620W | 640W | | --- | --- | --- | | Rated power | 620 Wp | 640 Wp | | Module efficiency | 22.18 % | 22.90 % | | Power density | 221.8 Wp/m² | 229.0 Wp/m² | | Open-circuit voltage | 55.60 V | 56.40 V | | Voltage at max power | 46.80 V | 47.60 V | | Short-circuit current | 14.08 A | 14.32 A | | Current at max power | 13.25 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 | 55.2 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, 620W:** 20,802 kWh - **Cumulative output, 640W:** 21,473 kWh - **Gap:** 671 kWh ## Output when hot | Condition | Cell temperature | 620W | 640W | Retained | | --- | --- | --- | --- | --- | | Standard test conditions | 25 °C | 620 W | 640 W | 100.0% of rated power | | Cool, bright day | 40 °C | 593 W | 612 W | 95.7% of rated power | | Typical summer roof | 55 °C | 566 W | 584 W | 91.3% of rated power | | Hot roof | 70 °C | 539 W | 556 W | 87.0% of rated power | ## Against the whole database | Measure | 620W | 640W | Out of | Note | | --- | --- | --- | --- | --- | | Efficiency | #5,930 | #2,359 | 14,005 | 640W leads by 3,571 places | | Power density | #5,869 | #2,389 | 14,005 | 640W leads by 3,480 places | | Heat behaviour | #2,165 | #2,165 | 14,005 | Tied - the same position in the database | | Weight | #9,586 | #7,363 | 14,005 | 640W leads by 2,223 places | | Warranty | #21 | #21 | 14,005 | Tied - the same position in the database | | Overall | #2,865 | #1,704 | 14,005 | 640W leads by 1,161 places | ## Questions ### Which panel is better: DAH Solar DHN-78X16/DG-620W 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 **22.18%**). 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-620W and DAH Solar DHN-78X16/DG-640W? **DAH Solar DHN-78X16/DG-**620 W**** has a module efficiency of **22.18%**, 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-620W use vs DAH Solar DHN-78X16/DG-640W? **DAH Solar DHN-78X16/DG-**620 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-620W and DAH Solar DHN-78X16/DG-640W? **DAH Solar DHN-78X16/DG-**620 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-620W and DAH Solar DHN-78X16/DG-640W bifacial panels? Both **DAH Solar DHN-78X16/DG-**620 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-620W vs DAH Solar DHN-78X16/DG-635W](https://comparepv.com/compare/dah-dhn-78x16-dg-620w/dah-dhn-78x16-dg-635w) - 3 differences, the largest is module efficiency - [DAH Solar DHN-78X16/DG-620W vs DAH Solar DHN-78X16/DG-630W](https://comparepv.com/compare/dah-dhn-78x16-dg-620w/dah-dhn-78x16-dg-630w) - 3 differences, the largest is module efficiency - [DAH Solar DHN-78X16/DG-620W vs DAH Solar DHN-78X16/DG-625W](https://comparepv.com/compare/dah-dhn-78x16-dg-620w/dah-dhn-78x16-dg-625w) - The same specification on paper - [DAH Solar DHN-78X16/DG-620W vs DAH Solar DHN-66Y18/DG-725](https://comparepv.com/compare/dah-dhn-78x16-dg-620w/dah-dhn-66y18-dg-725) - 12 differences, the largest is module efficiency - [DAH Solar DHN-78X16/DG-620W vs DAH Solar DHN-66Y18/DG-720](https://comparepv.com/compare/dah-dhn-78x16-dg-620w/dah-dhn-66y18-dg-720) - 12 differences, the largest is module efficiency - [DAH Solar DHN-78X16/DG-620W vs DAH Solar DHN-66Y18/DG-715](https://comparepv.com/compare/dah-dhn-78x16-dg-620w/dah-dhn-66y18-dg-715) - 12 differences, the largest is module efficiency --- Source: https://comparepv.com/compare/dah-dhn-78x16-dg-620w/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.