Solarproject 2020

This year I am realizing a long-standing project to bring solar power to our house roof. Sometimes it is good to wait a little longer so I could use brand new technology to build an island solution. But more on that later.

The blog is kept in diary form, step by step with all experiences.

The aim of the project is to implement an efficient solar power system with battery buffer storage and integration into the existing SmartHome installation based on KNX and / or OpenHAB.

February 9, 2020 Call for proposals for the project

The following framework conditions have been sent to four providers for the preparation of an offer:

The solar panels are to be created on the roof of the house in two fields and on the garage / workshop roof in a field with a southeast orientation.

There are approx. 48 sqm roof area which can be equipped with appropriate solar panels.

The solar power should mainly be used for own use and only the surplus should be fed into the power grid.

The current consumption is just under 6000 kWh.

A 3-phase 22 kW wall box for a future Renault ZOE is to be installed in the garage.

Due to the limited roof area available, high-performance PV modules with high efficiency must be used.

A solution with the lowest possible power loss and a long service life based on lithium-ion technology is to be used in the storage system. Possibly. is started with a smaller system, which should then be easily expandable at a later date.

The entire system should be designed in such a way that it supplies the household with electricity even if the external power grid should fail.

Potential SmartMeters must be integrable into the existing SmartHome installation.

May 4, 2020 Surcharge and first detailed planning

The response of the offers was very slow. The providers are pretty busy. Ultimately, I chose ebENERGIE from Holzgerlingen because ebENERGIE is the most technologically interesting offer where all components are coordinated and integrated. Elektro Breitling has also been with me in the past.

22 SunPower MAXEON 3 mono full black collectors are to be used as solar collectors, which are installed on Marzari metal roof panels.
The centerpiece is an E3/DC S10 house power plant with an 8.77 kWh battery which is connected to my house bus system with E3/DC KNX connect. An E3/DC wall box with 22 kW charging function for the electric vehicle is installed in the garage. And the E3/DC motor switch functionality provides the isolated solution, so that in the event of a power failure, the house can either continue to be supplied with power via the battery or solar energy can be recharged into the battery.

The battery can be expanded in the next few years.

Since our house is an old settlement house from the 50s and the general conditions for pulling the cables between the garage and the basement are somewhat difficult, I have agreed that I pull the cables between the two parts of the building.

In this context, I also wanted to set up the electronics in the garage and workshop and control all components via KNX.

However, we still have to wait until the project starts because the E3/DC components are still fairly new and will only be available in July.

June 8, 2020 Cable material

The cable material came from Elektro Breitling and I can start digging up the yard, drilling wall openings, installing cable ducts and pulling cables.

So that I can pave the yard again as it was once with the wild bond, I first took the paving picture and numbered the stones accordingly.






Wallbox charging cable NYY-J 5×6 mm² diameter: 19 mm, this will be a real challenge when laying.
Communication: UC900 SS23 4 P PE – UV diameter: 6 mm
Solar cable: Module +, Module -, grounding: H1Z2Z2-K 1×6 mm² diameter: 5mm
And when I have everything open I can rewire the workshop and garage and put everything in one control cabinet:
EIB bus cable green cable J-Y (ST) Yh 2x2x0.8 diameter 5mm
Telephone line I-Y (ST) Y 4×2.0 6 mm² diameter 5 mm
CAT7 cable Gigabit network cable PIMF copper network data cable AWG23 diameter 5mm
Power cable 5-way NYM-J5G 1.5 mm², gray diameter 6 mm
Power cable 5-way NYM-J5G 2.5 mm², gray diameter 7 mm
Hager AP small distribution cabinet Volta APV 2x12PLE IP30
EIB / KNX components:
JUNG 8472.01LEDW KNX double push button BA – push button position
2 MDT AKK-0816.03 Switch actuator compact, 8-fold
MDT AKK-0216.03 Switch actuator compact, doubleEltako power relay AR12DX-230V 0.1-25A 1 changer for dust extraction in my small carpentry, but more about that later.And lots of cable ducts, earth hoses, junction boxes, ….

June 12th – 22nd, 2020 pull solar cable

First pick up stones, there are quite massive granite slabs up to 10 cm thick … I’m looking forward to plasters again 🙂

What I had forgotten when digging up was the rain pipe from the garage, which had no chance against the pickaxe. Panzertape seals again.

What I completely underestimated were the breakthroughs in the walls. From the beverage cellar to the data center [WRZ Wittmann RZ :-)], then through the basement wall into the yard. The breakthrough from the yard into the workshop through the floor foundation first horizontally and then vertically was a special challenge. Finally, through the workshop wall into the garage and up on the stage. There was nothing to be done with my standard Bosch drilling maschine. Fortunately, friends of ours have a Bosch hammer drill that broke through the 30mm holes fairly easily.

In the workshop, the plasterboard ceiling had to be disassembled so that I could drill the holes in the garage or on the loft. This also increases the space in the workshop. A few years ago, I had already redesigned the loft floor.

After the breakthroughs, the entire cable canal had to be drawn and drilled on the ceilings or walls. I always had to keep an eye on the possible bending radius of the individual cables, but also what fit in which conduit or cable canal. And the workshop has received a new control cabinet, in which the entire cabling and all electronic components of the workshop and the garage are now neatly combined. All of this was more of a hard work, but also quite time-consuming.

The physically tough job. The granite slabs weigh up to 10 kg and there were approx. 30 slabs and 50 paving stones in addition to a lot of sand, split and gravel that had to be moved.

First of all, the trench with the cable protection pipes had to be lowered and the old ballast removed so that the larger number of cables fit under the paving stones and are not injured. In the afternoon there should be heavy storms and so I filled the ditch with the sand and split before all of it swims or fills with water. It was a good decision, it started to hail and rain heavily with 30 liters per square meter.

On Saturday I got two 25 kg bags with new 2-5 mm split. Then the ditch was dug up again and the material sifted into sand and split and the gravel stones sorted out, which were also three 20 liter buckets.
After the photograph of the plaster I took the large slabs again with the challenge that the slabs are of different heights and that the surface has to be prepared individually for each slab so that the surface is flat and the water runs in the right direction and not into the workshop. So it may be that a plate has to be picked up three or four times and to find the original plate for the place that everything fits together at the end. Finally, the individual paving stones are placed in the open gaps. When all the holes were filled and everything was flat, only the joints had to be filled. A little tip if you want to avoid weeds and moss in the joints, you take split and not sand, it is a bit more difficult to stop but it is worth it.

At the end of the day, I moved a ton of material by hand.

30. June Relaxing times

Due to the corona situation, the entire long-distance cycling events are canceled. So I took a 240 km tour to visit an old colleague in Heidelberg. The trip is documented on komoot with pictures: 🙂

01./02. July 2020 dismantling & construction workshop

The rest of the plasterboard ceiling had to be taken down in the workshop and disposed of again at a recycling company in Magstadt Then came the unpleasant job of sanding down the beams, totally dirty, with dust and all sorts of other things. Then the walls had to be repaired and plastered again. Then new paint came over it, now everything looks like new again.






03./04. July 2020 KNX programming

Workshop, garage and stage are to be rewired and all essential electrical components such as KNX, Ethernet, telephone, garage door, suction system and light are to be combined in a control cabinet in the workshop. The starting point is the KNX programming, which should control the main electricity consumers. After many back and forth and the current situation owed, the electricity consumers and the light are switched via an MDT AKK-0816.03 actuator. The garage door has already installed a Jung 2132.6 UP actuator in the control, which I will not change. The existing Jung 8472.01 LED W buttons and other new ones are used as switches.







Programming is done via the ETS5 software which is only available under Windows. This is my only program in a virtual Win10 environment in my Linux Ubuntu infrastructure. All KNX components are wired together via a two-wire, unstructured bus system independent of the 220 volt network, which makes the control and wiring of a home power network extremely flexible. Each component has its own program and communicates with all other components via telegrams. In other words, the entire system is decentralized and does not require a central server structure.

If one component fails, all others continue to function. After one day of programming, the components can now be installed and used immediately.

-> To be continued 🙂