Tesla powerwall 2.0 – straight dope message board electricity projects for grade 7

It just got installed, so technically we’re not supposed to even turn it on until it gets inspected by the city and the local utility company. I got that instruction verbally, but since the "on" switch is basically a toggle, I decided to try it out. So at 10am, not very good time for solar charging, this is what the app UI looks like. The image is static, but there are little moving icons that are directional between the circles. This shows the panels are generating 4.2 kW. The home is using 1.0 kW, the battery is receiving 2.3kW, and 0.9kW is going back to the grid. I’m still not sure the UI is an accurate reflection of what is happening, but I do notice it changing as I turn on and off the lights in the house with about a 2.5 second delay, so something is happening.

The powerwall was talked about in this thread before here, among others. I did opt for two batteries obviously. The old, ‘one is none, and two is better than one’ thing. The first thing people talk about when discussing solar I find is the break even point. I tend to think of it more from an ROI point of view, and in that regard I start getting return immediately. Overall though, cost is not the primary driver for me, though the cost has to not be prohibitive. The other benefits, backup, prepper wannabe, and supporting a budding technology that I believe in, are all very important.

We contracted with Solar City in December and have just now done the install. I would say the installation team was great, finished in a single day for both panels and batteries. The communications team and administrative coordinator was and continues to be very very terrible in that they have horrible communication, over promise, and fail to deliver.

It just got installed, so technically we’re not supposed to even turn it on until it gets inspected by the city and the local utility company. I got that instruction verbally, but since the "on" switch is basically a toggle, I decided to try it out. So at 10am, not very good time for solar charging, this is what the app UI looks like. The image is static, but there are little moving icons that are directional between the circles. This shows the panels are generating 4.2 kW. The home is using 1.0 kW, the battery is receiving 2.3kW, and 0.9kW is going back to the grid. I’m still not sure the UI is an accurate reflection of what is happening, but I do notice it changing as I turn on and off the lights in the house with about a 2.5 second delay, so something is happening.

The powerwall was talked about in this thread before here, among others. I did opt for two batteries obviously. The old, ‘one is none, and two is better than one’ thing. The first thing people talk about when discussing solar I find is the break even point. I tend to think of it more from an ROI point of view, and in that regard I start getting return immediately. Overall though, cost is not the primary driver for me, though the cost has to not be prohibitive. The other benefits, backup, prepper wannabe, and supporting a budding technology that I believe in, are all very important.

We contracted with Solar City in December and have just now done the install. I would say the installation team was great, finished in a single day for both panels and batteries. The communications team and administrative coordinator was and continues to be very very terrible in that they have horrible communication, over promise, and fail to deliver.

That’s pretty cool. I am also in a discussion with Solar City about a new system and also looking at the Powerwall. At this point, I’m not sure if I want to lease or buy, and if buy how I want to finance it. However, we received a $400 bill last month (it was particularly hot…hottest summer on record in fact), so that is driving our thinking on this. Definitely, update this thread as you get experience with this…I think there are a lot of potential customers for this on this board.

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.

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.

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.

• 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.

• 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.

• 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.