Doubtful that it gets any lighter. 
Do the batterys have any plugs or anything in them for you to use straight from the battery? You have the solar panels, you have the battery, now just get a Tesla car and plug it in and you’ve got the whole set!
You got me.
After a couple days, I think one of the batteries is not connected correctly. The battery array stops charging at 57%, but I think that may be a UI issue. When I listen to the batteries, when discharging, the fan is only operating in one of the units. Ahh well, I’ll contact support and find out. Technically I’m not supposed to have turned on the system yet, so I’ll delay calling them until then 
From my reading configuration issues are not super uncommon and support is able to resolve them relatively quickly so here’s hoping.
There is no plug to pull straight from the battery. If I want to get a specific plug to charge EVs, that has to be installed separately, but would likely pull from somewhere other than the battery IIRC.
It took a little while with customer service to diagnose the issue, they finally believed me about the 2nd battery not functioning correctly and after two site visits, the issue was a loosely connected wire. Now that I’ve had some consistent data, here’s where I was at for the past week.
The blue area is actual power consumption, yellow is solar power generation, green is battery activity, and gray is grid activity.
Here is an example for asingle day.
In the beginning of the day, the blue area is overlayed with the green, meaning we are using battery power to cover home usage. Around 8, the sun starts registering and we generate solar power and the battery gets charged. Just before 4pm, we had a power outage. When there is a power outage, the inverter for the solar panels resets so we stop generating solar for a few minutes, but the battery kicks in instantaneously. Just before 8, we ran the washer/dryer so we had a spike in usage but it was covered entirely by battery and solar generation. After about 8 the sun went down and the battery covered our utilization completely.
Pretty neat. What I learned after going through this process is that CA offers an SPIG credit. Tesla helped sign us up early, and since it’s first come first serve, we get a higher proportion of available funds. Based on our battery installation, we are slated to get around $9K, which almost covers the cost of the batteries. If I had known that, I would have bought another one.
I’m terrible with charts…
On the first link, your yellow (solar generation) is always above the blue (power used), does that mean you literally ran your house off the solar power alone?
The first chart doesn’t have any time of day metrics, just total day. So in a given day, yes I generated more power than I consumed every single day of the week. Obviously during the morning and evenings this wasn’t true at a point in time, so during those times the battery kicks in to make up the difference. The green bar above the line is usage of the battery, and the green bar below the line is the battery charging. The grey bar above the line is grid usage, and below is sending power back to the grid. On each of the 7 days, we basically used less than 1kWh from grid, I think like .1 really, except for Thursday. Not sure what happened there.
The time usage throughout the day can be seen on the second chart more easily.
Just an update on the powerwalls -
Since installation I have had a net utility bill of zero. That includes both electric and gas since the credits from the electric make up for the gas. I was going to wait a year before updating the thread, but since we use very little gas in the summer, I expect this to hold on an ongoing basis. During the winter we did use more electricity than we generated, but net net the credits thus far have exceeded the usage.
Oh very sunny days we generate about 40-45 kWh. Here’s the utilization since inception, with the numbers on the horizontal axis the month. Here is the consumption figuresover the same time period.
Things I’ve learned about the powerwalls that the brochures don’t do a good job of explaining:
[ul]
[li]Each powerwall can only backup 6-8 circuits, so if you have more than that, you have to pick which use the powerwall. Since we got two units, this was enough to cover the whole house.[/li][li]They run in parallel, so they drain through utilization evenly.[/li][li]They connect to your router via wifi, but there is no U/I to access this so if you change your wifi password you can’t reconnect the powerwall to the router yourself, you have to call them to come out and physically change it. That’s inconvenient.[/li][li]The PG&E (local utility company) credit for installation combined with fed credits exceeds the cost of the batteries. Total cost of batteries was $11K. 30% federal credit brings cost down to $7,700. PG&E SGIP credit for me is about $10K. The SGIP credit is limited however, so not sure if still available. I should have bought more powerwalls. The credit takes about 8 months to payout though, and there is a shit ton of paperwork.[/li][li]They can only backup circuits at 120v. Any dedicated 240v circuits are outside the spec of the powerwalls. This means that dedicated A/C units are not using energy from the powerwalls. For car charging, typically these are run off of dedicated 240v circuits. That means when I charge the car from the wall charger, I’m not pulling from the battery. That is kind of lame if you ask me, since it would be great to utilize the battery energy to charge the car. As a work around, I can charge from a normal 120v wall plug, but the charge rate is only 3mi/hour. That means I charge 30mi/day, which on most days covers the driving distance, and for that usage I am pulling straight from the battery. If I dip below a certain charge on the car, then I’ll use the wall charger and be able to get a full charge in a night. Since we are sitting on credits for the utility bill, I figure that works too.[/li][/ul]
Now I need to install a well for water
Very cool! Thanks for the detailed report. I am very interested in modern solar and battery tech. Unfortunately, I don’t own a roof.
Haven’t you guys run out of groundwater by now? I thought you have to hydrate solely with Zima and Napa chardonnay.
This thread makes me angrier and angrier every time I read it. No, not because of you, but because I’ll (probably) never be able to afford something like this and I want to so, so badly.
Congrats on everything! Love that it’s working out for you!
Hey, we had a decent year last year. And this year ain’t so bad either. I live near a stream that is pretty well fed. I’m pretty sure there is an accessible water table nearby since my neighbor has an active well they use for irrigation. The cost of drilling to find water is about $20K, and no guarantee you hit it. Then you have to install all the actual equipment. I’ll probably do it, but in a few years down the road. For now, our utility footprint is much smaller.
I’m curious: I assume you’re on municipal water now. Are you allowed to drill a well if you’re already in a water district? Do you have sewer service?
I think it’s allowed but I haven’t explored the permitting. I know my neighbor has both municipal water and sewer, and also has a well for irrigation. I figure it’s okay but I’d have to check before executing.