1500 Watt with Solar Panels

Posted by Jeroen van Agt in Solar energy 6 Comments»

The installation of 12 solar panels with a total of 1500 Watt peak. Information and tips about the installation and how to maximise its yield.

1500W aan zonnepanelen

The solar panels

After my enthusiasm about my first solar panel I started to inform myself on the costs of additional solar panels. After some investigation on the internet I found the following kyocera KC125GHT solar panels.

Plaatje van Kyocera KC125GHT zonnepaneel

Kyocera KC125GHT solar panel

These panels have a high cell efficiency of 16% and peak power of 125 Watt per panel.


I bought these panels for my own company SoftNow.com. In the Netherlands the goverment provides tax benefits for companies which invest in renewable energy. Therefore I only had to pay effective 1/3 of the cost price. With my investment budget for 2005 I was able to buy 12 new Kyocera solar panels, enough for 1500 Watt peak of solar power.


The Kyocera solar panels provide DC which needs to be converted into AC to be able to connect the solar panels to the 220V AC utility grid. You need a solar inverter to do that. By connecting as many solar panels in series as possible you need less inverters and thus less costs. After some investigation and price comparisons a have finally chosen the Sunmaster QS2000 invertor of Mastervolt.

Mastervolt QS2000 Invertor

The Sunmaster QS2000 solar inverter

The Mastervolt inverter has a maximum input of 1800W DC, which makes it possible to connect all 12 solar panels (in series) to a single inverter. The solar panels generate a maximum of 1500 Watt peak, so there is some room for expansion in the future.

The Mastervolt inverter is mounted indoor, which is good for its life. An inverter which is mounted outdoor has to cope with a lot more temperature changes which is bad for the life of the inverter.


When placing the solar panels it is of utmost importance that all panels are not in the shade. When one or more panels are in the shade this has a big influence on performance because they all operate in series. The efficiency drops hard, more than you would expect, when a small number of solar panels are in the shade. If shade is unavoidable, because of some fixed objects like a tree or a chimneys, you can consider to use multiple chains of solar panels so that not all solar panels are effected. However you need more or a special inverter with multiple inputs. The QS2000 inverter can connect two parallel strings of solar panels.

De afstand tussen de panelen is van belang

The solar panels mounted on my flat roof

On a flat roof the distance between the rows of the solar panels is very important. When the distance is too small, one row will throw another row in the shade as soon as the sun drops lower. Especially during winter time. As a rule of thumb the space between the rows is twice the height of the panels (measured from the roof).

Minimale afstand tussen de zonnepanelen

Space between the rows is twice the height of the panels. Source: solaraccess.nl


When ordering the panels it is important to mention on which type of roof they need to be mounted. There are different mounting systems for flat roofs or roof tops with a angel. Your supplier (at least in the Netherlands) will also provide the mounting system together with the solar panels. In my case I ordered a flat roof system.

Het aluminium frame waar de zonnepanelen geplaats gaan worden

Clear the roof of stones before placing the solar panel mounting frame.

Before placing the solar mounting frame on the roof all stones need to be removed from the roof top. Otherwise there is a chance that one of small stones will be pressed through the roof top because of the immense weight what will be added later to fix the position of the frame. Rubber tiles are put below the frame to protect the roof.

Rubberen plaatjes onder het frame

Rubber tiles protect the roof

Angle and orientation

The solar panels are mounted with a fixed angle of 27.5 degrees. The angle is determined by the construction of the aluminium frame. This angle is chosen so that the panel will be flushed clean after a rainy day and catch an optimum amount of sunlight in the summer -and winter time.

My house is located in the Netherlands. Therefore my optimum orientation for the solar panels is south. See also the diagram in the article about the Instralings diagram.

Adding weight

To prevent my panels to fly away in a stormy winter I need to add weights to fix the frame on my rooftop.

Verzwaring van het frame

Adding enough weight is very important

The amount of weight depends on the geographical location and its wind conditions. The guidelines for the Netherlands can be found the table below.

Height Coast area Inland
Less 8 meter height 75 kg per panel 50 kg per panel
More than 8 meter 100 kg per panel 75 kg per panel

For weight I used Dutch “grindtegels” (concrete tiles) of 40x60x5 cm. These weigh around 25 kg apiece. I found them on a online second hand market (marktplaats.nl) where I could get them for free (most people want to get rid of them)


After manual heavy lifting (1200 kg of tiles, 6 meter high) and constructing the panels, the solar panels are now finally ready for use.

1500 Watt aan zonnepanelen

Twelve new beautiful solar panels ready for use.

The yield

Unlike my first solar panel the Kyocera solar panels have reached their maximum of 1500 Watt peak. Beter even, the highest measured power I saw was little more than 1600W. The invertor has an efficiency of approximately 95% which means that I am delivering more than 1520W back into the utility grid.

Annually the solar panels should generate around 1350 kWh of electricity. Measurement indicate that this is about right. On my best day (12-6-2006) I have generated 10,03 kWh. The panels worked for 15 hours and 35 minutes. The longest day was 17-6-2006, the panels worked for 16 hours and 10 min. They had generated 15,38 kWh, however, at that time I had already installed 6 additional panels. You can read more about that in the article 2500 Watt with Solar Panels.


6 replies on “1500 Watt with Solar Panels”

This is definitely the best solar energy post I’ve stumbled today. I love the fact that it’s real-life experience based and not just a “what-if” scenario like most blogs post.

I run a blog about green energy which focuses mostly on solar energy. I’ll admit, I’m probably the biggest hypocrite alive though as I do not own a single solar panel.

I am however very passionate about going green, and have taken every available step I can to live a smaller carbon footprint lifestyle. My hopes is to earn an income on my blog which will help me buy and install a solar panel system on my house.

Thanks for sharing your system. I love the fact it’s on your business rather than your home. You’re an inspiration.

I did not fully understood why connecting the PV panels in parallel would increase the amount of inverters? as it is said: “By connecting as many solar panels in series as possible you need less inverters and thus less costs.”.
If it is because the inverter does not have enough plugs: you could connect PV panels in parallel and then before plugging it into the inverter just connect them together to one main plug which will be plugged into inverter.


A typical solar inverter can have 1-3 strings of solarpanels (in serie). My inverter (2005) has an option for connecting 2 strings. You also need to have solarpanels connected in serie to achieve the minimum amount of voltage and power for optimum MPP (Maximum Powerpoint Tracking).

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