Tesla Powerwall

After our first full calendar month since we moved in, we can share our thoughts and experiences with our Solar Panels and the Tesla Powerwall.

It was May (probably the best month of the year for solar energy, at least in the northern hemisphere) and of course, we really need to wait a full year to have the full picture.

Here is an analysis of a really sunny day – 27th May

  • Colour coding for the screenshot below is:
    • Green is the electricity which the system produced (almost no clouds that day)
    • Blue is the own-produced electricity we used
    • Red is the electricity we bought from the grid (not very much!)
  • 25 kWh electricity was produced that day
    • 11.8 kWh of which we used ourselves
    • 13.4 kWh of which was exported (some of the ‘exported’ electricity will have been used by out heating/hot water system which is on a different electricity meter, but it was a hot day with no heating required, so most of it would have been sold to the grid!)
  • Since almost all of our electricity usage on that day was at a time when there wasn’t much electricity being generated (we were not home at lunchtime!), 53% of our usage came from the battery, rather than directly from the panels. On a day like this, the battery clearly makes a huge difference to how much electricity we bought that day.


Other statistics for May:

  • Despite a wet start to the month (almost the first week there was no sun), on 21 out of 31 nights, the battery had enough charge to last all the way through the night.
  • Between 8:00 am on 20th May and 5:30 am on 31st May (11 days), the battery was almost never flat, with only an hour or two on a couple of days where it didn’t quite make it through the night and went flat just before the solar panels were producing again.
  • In total (including the heating/hot water system) during May:
    • We used 559 kWh in total
    • We bought 255 kWh from the grid
    • We sold 163 kWh to the grid
    • We used just 92 kWh more than the system produced.

A Sunny Day

On Saturday and Sunday we were busy with the skirting board upstairs. The Stanley 1-20-800 Dynagrip Adjustable Mechanical Mitre Saw that we bought last week is really good, and all of the angles were easy to cut.

We’re pleased with how it looks.


Since we were cutting outside to have enough space, we enjoyed the warm sunshine, especially on Sunday which was completely free of clouds from dawn until dusk.

The solar panels exceeded their previous record, with a total of 20.45 kWh produced on Sunday.

It’s not yet been a week since the solar panels were connected up, and already (as of Monday evening), the system has generated 78 kWh.

The House is Effectively Finished!

Friday again, and after further visits by the electricians, the decorators and the interior door guy over the past couple of days, we can now say that all work has effectively been completed.

Over this weekend, we are hoping get all of the skirting boards done on the first floor, and to install some temporary light bulbs in the rooms where the electricians haven’t already done so.

There are still a couple of very minor things to be done. Silicone is not yet done in a couple of places, there is a little bit of painting to be finished here and there and the electricians still have not managed to correctly align the satellite dish, but that should all hopefully be done in the next few days, ahead of our ‘pre-delivery inspection meeting’ on Wednesday.

Also during that meeting, the blower-door test will be carried out for our energy efficiency certificate, and the heating will be switched to heat-pump mode.

Solar Power: We still haven’t had a really sunny day, but already the solar panels seem to be performing well compared to the assumptions we made some months back based on another installation in the area.

  • Wednesday – 13.78 kWh
  • Thursday – 7.04 kWh (Would have been higher, but was switched off from 10:15am to 1:45pm due to the electrician work)
  • Friday – 9.68 kWh

We have now started a snag list of all the things that need to be finished / improved, but really up to now are impressed with the quality of most the work that Viebrockhaus and their contractors have done. We are also very impressed that they have pretty much kept on time throughout – as many things have been early as have been done late (which was anyway mostly due to icy weather).

The dust sheets that were covering most of the floor tiles downstairs have been removed today and on Monday or Tuesday a cleaning company (paid for by Viebrockhaus) is coming to do an initial cleaning. We will take some more photos after that, but for now here are some pre-cleaning photos…

We now have an appointment for our kitchen to be installed on 27th and 28th April (although they are apparently still waiting for some doors which might not arrive until slightly later).

Since we are eager to move in (and because we don’t want to extend our holiday into the next week), we have changed the van hire to 25th and 26th April, and will probably now move in before the kitchen arrives. We can survive with a microwave and a kettle for a couple of days and we do also have a portable kitchen we could park outside the house if we really want to!

Solar Power – Day 1

Today was the first full day of solar power production. Unfortunately, it was not as sunny as most of the days in the past two weeks, but none the less reasonably bright and partly sunny.

Since we have installed an LTE(4G) Router, we have been able to connect the solar inverter to the Internet and can already log into the monitoring portal, and we can see that the roof has produced 13.79 kWh of electricity and that the battery is fully charged.

We’re looking forward to a sunny day to see how much more can be achieved…

Solar Inverter & Battery Installed

This morning we had an appointment with a man from the electricity company who came and installed our electric meter, so now we are connected to the mains electricity supply. The temporary supply should be gone tomorrow.

At the same time, the electricians and the solar installer were there to install the battery and connect the solar panels and to switch everything over to the mains supply.

The black bracket on the wall is for the battery. Since there wasn’t quite enough room to fit in the battery without it blocking access to the light switch, we have moved the light switch outside the room (exactly where it was, but the other side of the wall).

The battery standing in the hallway, waiting to be brought downstairs to the cellar.

Four people were needed to take the battery down to the cellar – it weights something like 100kg!

Now it is in it’s place, and by mid afternoon was charging itself from the solar panels.

The electricians will be back tomorrow, as they still have some relatively minor things to do.


Tesla Powerwall -> LG Chem Resu 7H

We heard at the end of last year that Tesla had discontinued their original Powerwall (replacing it with a new model), and also that in future Viebrockhaus would switch to a competitor product from LG Chem

Since then we have been unsure which of them we would actually get. We guessed that it would be dependant on how much stock of the Tesla Powerwall was left at Viebrockhaus.

We still haven’t received any official information from Viebrockhaus, but we have heard from the construction manager that he thinks we will get the LG Chem RESU 7H, rather than the Tesla product.


Our Place in the Sun & Upstairs Flooring v2.0

Finally, it’s the weekend and we have been to see the house without the scaffolding in daylight! In the pictures, it’s easy to see how the reflective surface of the bricks makes the whole house look a different completely different depending on the angle of the sun.

The first pictures were taken at 10:40 am. This is the east side of the house.

In the next picture (still at 10:40), the (south facing) roof is partly in the shade from the neighbour, but the solar panels were already in the sun. When the sun is a little higher in the sky than it is right now in January, it will be shining on the complete side of the house quite early in the day.

For the next one (now about 10:45), we decided to clear all of the pieces of wood and polyethene out of the way (we only did this in Photoshop!)

We drove by again on the way home to see how it looked in the afternoon sun. At 16:10 the whole of the south and west sides still in the sun.

Maybe we’ll be adding a parasol to the shopping list!

Upstairs Floor v2.0

As mentioned a couple of days ago, the Logoclic Aqua Splash click-vinyl flooring that we chose back in October doesn’t seem to exist anymore. In a similar way to the product’s website page now just says “page under construction”, the display in the DIY store just an empty rack (although the promotional poster is still there at least for now).

We asked the in-store Logoclic expert why it was no longer available but he either didn’t know or perhaps he had been sworn to secrecy.

In October they had told us that a range of new colours/designs had just launched and that they expected even more in the coming months.

The product has even won two Plus X Design Awards. Their loss. We then went to a different DIY Store.

After a brief stop for bratwurst and chips, we have found and have now decided on this laminate floor that is a very similar in colour to the first choice, which is also quite a bit lower priced. It is not suitable for bathrooms (or other wet places), but since we are only putting it in the bedrooms/landing – this is not important for us anyway.



The Roof is Finished, Structural Build is Complete

Not only was our roof-tiling finished yesterday, but the solar panels have been installed as well! According to the plan, they were going to be installed around the middle of January, so it’s a new record for something happening early!

Unfortunately they are not connected to anything yet, so we still only have electricity coming from the orange box outside.


So now we will have to wait a really long time before anything else will happen. Maybe we’ll use the time in between to start thinking about the driveway and garden…

Merry Christmas and a Happy New Year!