I am not getting paid by Tesla! I need to say that, because I absolutely love my Tesla battery. Now that I have had it for 8 months, I wanted to give an update. I installed 13 solar panels- whatever the highest output is today that you can get per panel- I don’t remember, but around 330w each. I only put in one Tesla Powerwall. My main goal was to get off the grid during normal use and ensure backup power for our many power outages. Where I live, it is a regular thing to have power go out for anywhere from an hour to a whole day. Also, after the storms in 2017, I was without power for 128 days.
Because I live in the historical district, I was not allowed to put panels on the south side, which faces the harbor, except for the shed roof over the porch that can’t be seen from the water. They don’t want to spoil the historic view of town from the water with all the red roofs. I was worried I would not have enough power due to not being able to put panels on the south-facing side. I ended up fitting four on the shed roof on the south, four on the east, and five on the west side. This was actually a blessing, because I have panels directly facing the sun in the morning, noon, and evening. My battery is fully charged by noon. I start making power before 7AM and it keeps on until 6PM. The battery keeps me going all night and is 50% or more by morning, so I have plenty of battery left.
I am making more power than I use, so I bought a freezer and started leaving fans on all day to keep the house aired out. Side note: I have A/C but we never use it except when guests are visiting that are not used to the heat. If I were to use the A/C, it would require another battery.
My biggest surprise is that the dryer will run off-grid as long as I run it during the peak solar hours between around 10AM and 3PM. I did not expect that. I do laundry on Saturday and Sunday and schedule it around the peak solar. I run the washer in the morning and then around 10AM start the dryer while the second wash runs. I go to the shop and play around, come back, and throw in another load for the dryer.
One thing with the Tesla Powerwall is that it constantly checks the grid by pulling bursts of 0.1 kw. If you want to be completely off the grid you have to shut off the service breaker, but then the Powerwall will not do any updates, so I was told not to do that. It only will update if it has grid power so that it isn’t robbing power during an outage. So, in the following usage, you are going to see spurts of 0.1 from the grid, but it isn’t because it was not getting enough power- that’s just what it does.
Here is Saturday. The battery is green, solar is yellow, and the grid is gray. Blue is what the house is using. In this example, the battery was supplying power until morning, then solar kicks in and the battery is charging. The battery fully charged before noon, which is typical. Even on a rainy day, it is charged by 1PM at the latest. The next power blip is when I ran the washer, which ran off solar and battery, then solar recharged the battery. I did some shopping, came back, and ran the dryer. The house pulled more power than solar could supply, so the battery made up the difference. The grid did the usual 0.1 power blips which again is what it does normally unless you switch off the grid. After the dryer stopped, it charged the battery off solar, and then used solar to run the house until sundown, and then went back to battery. Side note: the graph only shows how much solar you are USING- not how much you are generating. So between noon-ish and around 2PM it just didn’t need as much solar, but the panels were supplying much more. Usually during peak hours I am making just over 3kw.
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Aroud 8AM today, the battery is at 62% and charging, so it was likely well over 50% by sun up. I intentionally hit the screenshot while it had a 0.1 pull from the grid, which it does when charging the battery- I am told to check grid and maybe to ensure clean power. It does that for like one or two seconds only.
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I love my solar!!! Not only am I not using the very expensive grid power, but I have no stress about power outages. Now here is a note for you statesiders: it won’t pay for itself. We have the second highest per-kWh rates in the entire world and it will take a while to pay for itself here. What it does is give peace of mind and also is one less person using the grid, which here runs on diesel generators. If you add an electric car, you might actually see a benefit dollar for dollar when you factor out fuel costs for a car. I wanted to get an electric car to use the power I am not using after the battery charges. I no longer work from home, so that idea is out. I could, however, store the power if I had a second Powerwall and use it to charge the car at night.
I am sharing this for those that are considering going solar. I live at 18* Lattitude, so I get more direct sun during the day, but I also have shorter days during the summer than you northern folks. During winter my days only shorten by around an hour, and we don’t get the gray skies you guys see more of in winter. Probably up north you would need a few more panels than this. I am on the south side of the island which gets sun all day, and I don’t have trees blocking my sun. Total cost installed was $27,000. This is also much higher than those of you in the states would pay. Everything here costs more money.
As you see, I could have generated more power during the day if I could have utilized that south-facing roof, but I do get more power in the AM from the ones facing directly east- in the shadow at time of this photo, taken around 2PM if I remember correctly.
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Originally Posted by Brian Elfert
