Our basic rule: on flat roofs we only install panels shorter than 2 m. The LONGi 480 W (1.80 m) and DMEGC 515 W (1.98 m) suit both homes and industrial halls, including flat roofs. The AIKO 650 W and the Gokin 630 W and 650 W panels are 2.38 m long. We install these on homes with limited space, on industrial halls with sandwich-panel roofs and on the ground.
Why does length matter? On a flat roof, the panel sits on a tilted structure and is held at only a few points. Wind and snow load it much more than on a pitched roof, where the panel sits parallel to the roof covering. With a panel longer than 2 m, the frame can bend. That is why we make no compromises here, even if a large panel would offer more watts.
The panels compared at a glance
| Brand and model | Power | Format | Efficiency | Where we install it | Availability |
|---|---|---|---|---|---|
| LONGi Hi-MO X10 LR7-54HVD-480M | 480 W | 1800 × 1134 × 30 mm | 23.5% | Homes; industrial halls and buildings with flat roofs | In stock |
| DMEGC DM515G12RT (G54HBW / B54HSW) | 515 W | 1977 × 1134 × 30 mm | 23.0% | Homes; industrial halls and buildings with flat roofs | In stock |
| AIKO AIKO-A650-MAH72Mw | 650 W | 2382 × 1134 × 33 mm | 24% | Homes with limited space; industrial halls with sandwich-panel roofs; ground mounts | In stock |
| Gokin GK-3-72HGBD (BC, dual glass) | 650 W | 2382 × 1134 × 30 mm | 24.1% | Industrial halls with sandwich-panel roofs; ground mounts; large orders | Container orders only |
| Gokin GK-4-66HTBD (TOPCon, bifacial) | 630 W | 2382 × 1134 × 30 mm | 23.3% | Ground mounts; industrial halls with sandwich-panel roofs; large orders | Container orders only |
The LONGi data come from the LR7-54HVD datasheet. For DMEGC, see the G54HBW and B54HSW datasheets. The Gokin 630 W panel is listed in the GK-4-66HTBD datasheet. AIKO is presented on the panel's product page in our shop.
The efficiencies refer to the power ratings in the table, under standard conditions. They are not percentages of savings on your electricity bill. Quantity and delivery time are determined for your project.
Six practical scenarios: what we choose and when
1. House with a pitched roof: LONGi 480 W or DMEGC 515 W
For most homes we start with LONGi or DMEGC. Both are under 2 m, easy to handle on the roof and fit well on slopes with dormers, chimneys or roof windows. LONGi is 1.80 m long and has a uniform appearance, with no grid on the front. DMEGC is 1.98 m long, dual glass, with a very good price-to-quality ratio.
We compare how many panels fit on each slope and the resulting total power. Read our LONGi Hi-MO X10 480 W guide and DMEGC overview.
2. House with limited space: AIKO 650 W
When the roof is small but you want as much power as possible, we choose AIKO. With 24% efficiency, it gets more kilowatts out of the same area. On a pitched roof, the panel sits parallel to the roof covering, on a structure fixed to the roof framing, and its 2.38 m length is not a problem.
Fewer panels for the same power also means fewer clamps and connections. See where we use the AIKO 650 W and how ABC technology works.
3. Industrial hall or building with a flat roof: LONGi 480 W or DMEGC 515 W
On flat roofs we only install panels under 2 m. Here we choose LONGi or DMEGC, on tilted structures sized for wind and snow. We do not put 2.38 m panels on flat roofs, because the frame can bend. Installation details are in our flat roof installation guide.
4. Industrial hall with a sandwich-panel roof: AIKO 650 W or Gokin
On sandwich panels, the modules sit close to the roof, on profiles fixed to the roof covering. Here large panels are an advantage: fewer pieces for the same power and faster installation. We choose AIKO when power per area matters. Nectaria installed 807 AIKO panels on an industrial hall in Alba County, in a project of approximately 520 kWp.
The Gokin 630 W or 650 W comes into consideration when cost per kW and quantity matter more. We do not keep Gokin in stock: we bring it in by the container only. Before installation we check the roof capacity, skylights and access.
5. Ground-mounted system: AIKO 650 W or Gokin
On the ground there are no roof limits, so we use large panels. AIKO delivers the highest power per area. The Gokin GK-4-66HTBD 630 W is bifacial and can also use light reflected from the ground. The Gokin GK-3-72HGBD 650 W has back contacts and dual glass, with 24.1% efficiency. Details on the range are in our Gokin Solar guide, and on the structure in our guide to ground-mounted systems.
6. Large orders for installers: from stock or by the container
For installation companies, the LONGi 480 W, DMEGC 515 W and AIKO 650 W are in stock at our warehouse in Alba Iulia. The Gokin 630 W or 650 W is not in stock: we bring it in by the container only, for large projects. Nectaria imports directly and distributes to businesses across Romania. See our page for installers.
When a bifacial panel is worth it
The LONGi LR7-54HVD and the bifacial DMEGC and Gokin variants can use light on both sides. On the ground or on a roof with a light-coloured surface, the geometry can allow a useful rear-side contribution. On a pitched roof, with the panels close to the roof covering, this contribution is usually small.
We do not use a fixed percentage of gain for all installations. First we analyse the layout. Likewise, the back contacts of AIKO ABC and LONGi HPBC 2.0 describe the cell technology; they do not replace a site analysis. For background, read our AIKO and LONGi guide on efficiency.
Start from the building and the project timeline
Send us the dimensions, photos of the roof and the quantity you need. We install in Transylvania and deliver equipment across Romania. You can pick up goods in Alba Iulia, str. Livezii nr. 35A.
Explore the panel collection and our systems without batteries. Call 0723 172 359 or message us on WhatsApp. Together we will choose the panel that suits your project.
Leave a comment
This site is protected by hCaptcha and the hCaptcha Privacy Policy and Terms of Service apply.