Buying a solar system
The dutch goverment wants to have as much "green" energy as possible of course, it will be the same in other countries I guess. To support home owners to buy solar installations for private use we can now buy these VAT free. And of course if you're able to install these yourself it is possible to buy a reasonable installation for about 2000 euro. With the current and rising electricity prices and the increasing amount of electrical things at home this is of course very interesting. I really don't care about the impact on the environment in which I do not believe. See my post here: https://pe4bas.blogspot.com/2019/01/energy-transition.html. So we decided to order an installion of 8 solarpanels which we thought to mount on top of our glasshouse.
Installation
Because I wanted to do all installation myself it was a great opportunity to see what I could do to prevent QRM. The inverter is placed behind the wall of the glasshouse on just about 10m from my antennas. I already have much noise from neighbours surrounding solarpanels (they use optimizers) so I really didn't want to have a increased noise from my own installation.
The first challenge was how to mount the panels on the glass. Normally solarpanels are mounted on a roof with tiles. I invented simple aluminium frames on which I could mount the aluminium mounting rails that were supplied with the panels. I could mount 4 panels per frame. The total weight of one frame with panels would be approx. 100kg. The next challenge was how to mount everything on the glasshouse without breaking the glass. The idea: place the frames on the lower end of the "roof", mount the panels on the lowest rail and hoist the frame up the "roof" with ropes. Luckely the glasshouse consists of aluminium profiles which hold the glass plates sealed with a kind of rubber strip on top. The frames could slide over the rubber strip without breaking the glass. Well, in the end I managed to break four glass plates, but they were easily replaced. Luckely I was able to hoist the frames myself. The frames are secured on top of the brick wall. The lower end of the frames is not yet secured, I have to invent something for that since I cannot secure it to rubber, glass or the aluminium profiles.
Preventing QRM/noise
Time to install the wiring. Of course I already got information how prevent radiation from the system as good as possible. The things I did:
- Prevent a loop with the DC cable. The panels are connected in series. The positive and negative wire are running back as close as possible to the connecting wires in between the panels.
Alu duct running up the wall |
- The positive and negative DC wires are running through the center of the 8 panels in between the two frames up to the wall. I mounted the inverter on the other side of the wall. I twisted the wires the whole length to the inverter.
- Where possible I run the twisted DC cable through aluminium earthed ducts. Both frames and the solarpanel(frames) are earthed to the mains earth.
Large ferrites |
- Ferrite material #31 clamps are placed on the start of the positive and negative returning DC cables. Ferrite clamps also placed at the point were cables are going up and on top of the wall.
- Ferrite FT240 #31 torroids placed just below the inverter at the DC wires and the AC cable.
So far I didn't notice any increase of noise on any of our hamradio bands.
For free
Free energy from the sun. Like it or not but it seems to work well. And it is possible to have it without QRM/noise if you ensure a good installation.
Unfortunately we didn't have much sun last week. But at least 27 kWh in just 6 days. Enough to run at least my radios/computers for free. |