NorCal, Tesla 4kw + 1 powerwall

[Ampster]

Great thoughts. I've seen speculation that future powerwalls (3?) may simplify the h/w needs. Incorporate the inverters etc. I'm looking forward to what the future holds !!

The Powerwalls already have an inverter and that is why they can AC couple to any UL 1741 GT inverter. The first versions of the Powerwall were DC coupled only to Solaredge Storedge inverters and those only had DC to DC converters. That was an efficient system but it left Tesla subject to a only a single vendor solution. The new Gateway has room for more breakers so a few critical loads circuits can be added without the need for a completely separate panel.

I do think the future will have a lot of AC coupled solutions. California is leading the market with installations.

[Wannaretireearly]

I think there is more demand for home storage than supply, but battery prices are coming down. For Tesla cars, the battery costs are around $150 per KwH, which implies a price for a 14 KwH Powerwall cost of $2100 = $150*14. Then you have to include the price of the inverter and other things. Batteries will get much cheaper and last much longer. All major countries and investing heavily in battery manufacturing capacity and battery research. China will probably be the leader in batteries as they are in solar currently. Wholesale solar modules prices are at an incredibly low price of 17 cents a watt. Now, panel manufactures are focusing on raising solar panel efficient to lower balance of system costs.

Great thoughts. I've seen speculation that future powerwalls (3?) may simplify the h/w needs. Incorporate the inverters etc. I'm looking forward to what the future holds !!

[solar_future]

Its also interesting that solar prices have dropped quite a bit last few years. Whereas the battery prices have gone up. I get the demand from cars is a big impact. Wonder what Powerwall 3 will look like and how aggressive Elon will get with powerwall pricing next few years...

I think there is more demand for home storage than supply, but battery prices are coming down. For Tesla cars, the battery costs are around $150 per KwH, which implies a price for a 14 KwH Powerwall cost of $2100 = $150*14. Then you have to include the price of the inverter and other things. Batteries will get much cheaper and last much longer. All major countries and investing heavily in battery manufacturing capacity and battery research. China will probably be the leader in batteries as they are in solar currently. Wholesale solar modules prices are at an incredibly low price of 17 cents a watt. Now, panel manufactures are focusing on raising solar panel efficient to lower balance of system costs.

[scrambler]

I wish I could limit my energy usage to 10kwh per day but that would require me to send my wife and daughter away somewhere. Neither can do without AC.

It sure depends where you live.
Where I am, most days I can cool the house down by opening windows and sliding doors, and letting the cross breeze do the job

But is is more than 10kWh per day, you get that for the night and then the full 30/40 kWh from solar during the day.
The limit though is the sustained power output, as 4.5kW is not enough to run AC plus many house loads at the same time. So the real limit is in the max power, not the amount of energy available.

[Wannaretireearly]

Its also interesting that solar prices have dropped quite a bit last few years. Whereas the battery prices have gone up. I get the demand from cars is a big impact. Wonder what Powerwall 3 will look like and how aggressive Elon will get with powerwall pricing next few years...

[SunEagle]

In my experience it is more than enough to last through the night and next morning you have solar to recharge and power the house. The combination of the two means I can last indefinitely and comfortably with that setup.
Ultimately, you would need to look at your personal consumption to verify that evaluation. Eventually make a test run over a full day to limit your usage to all the "small loads" and then download the POCO data for that day and look at the hourly usage. and compare that to a day of solar and an evening and night of 10kWh battery.

I wish I could limit my energy usage to 10kwh per day but that would require me to send my wife and daughter away somewhere. Neither can do without AC.

[Wannaretireearly]

In my experience it is more than enough to last through the night and next morning you have solar to recharge and power the house. The combination of the two means I can last indefinitely and comfortably with that setup.
Ultimately, you would need to look at your personal consumption to verify that evaluation. Eventually make a test run over a full day to limit your usage to all the "small loads" and then download the POCO data for that day and look at the hourly usage. and compare that to a day of solar and an evening and night of 10kWh battery.

Thanks! Great points

[scrambler]

In my experience it is more than enough to last through the night and next morning you have solar to recharge and power the house. The combination of the two means I can last indefinitely and comfortably with that setup.
Ultimately, you would need to look at your personal consumption to verify that evaluation. Eventually make a test run over a full day to limit your usage to all the "small loads" and then download the POCO data for that day and look at the hourly usage. and compare that to a day of solar and an evening and night of 10kWh battery.

[Wannaretireearly]

I find that the capacity of one Powerwall is sufficient to provide great comfort and peace of mind towards foreseeable outages in North California.

During an outage, 80% of the comfort is to keep lights, Internet, computers/TV, washing machines, microwave etc... and for that the equivalent of one Powerwall combined with the fact you can still use Solar is more than enough.

Giving up AC, a big electric oven or dryer for a few days are not a huge deal.

But would one power wall last more than 12 hours, even with limited use? Agree giving up AC, oven, dryer not a big deal.

How long would you expect one powerwall to keep 80% of your comfort going? Thanks

[scrambler]

I find that the capacity of one Powerwall is sufficient to provide great comfort and peace of mind towards foreseeable outages in North California.

During an outage, 80% of the comfort is to keep lights, Internet, computers/TV, washing machines, microwave etc... and for that the equivalent of one Powerwall combined with the fact you can still use Solar is more than enough.

Giving up AC, a big electric oven or dryer for a few days are not a huge deal.

[Wannaretireearly]

Didn't previous calculations show that the Powerwall has a positive return on investment because of time of use differential pricing?

It did, to a degree. I dont think those calcs took into account net metering though I'd have to go back and look). It's been a tough decision for me: I wasn't happy 1 powerwall would provide very limited backup, and would require significant re-wiring for limited backup. Also, would not be easy to add a second powerwall with more rewiring/panel work needed etc.

Given above, I'm trending towards dropping the batteries, and perhaps pick it back up in a couple of years. Not sure if that's my best decision...

[solar_future]

Quick update. Talked to my rep who helped me add 3 panels to my design (total: 15 panels). Makes me more comfortable/future proof with my current annual use around 7200 kwh. They are working on an updated quote/contract. I also dropped the powerwall. One pw just doesn't seem worth it. 2 too much $. Hope we continue to be lucky with the rolling power outages from pge.
I will continue to consider batteries/backup as prices and options get better next few years.
Site plan for permit is trow AM. Anything I should double check? Should be pretty straightforward with only panels being installed....thanks

Didn't previous calculations show that the Powerwall has a positive return on investment because of time of use differential pricing?

[Wannaretireearly]

Quick update. Talked to my rep who helped me add 3 panels to my design (total: 15 panels). Makes me more comfortable/future proof with my current annual use around 7200 kwh. They are working on an updated quote/contract. I also dropped the powerwall. One pw just doesn't seem worth it. 2 too much $. Hope we continue to be lucky with the rolling power outages from pge.
I will continue to consider batteries/backup as prices and options get better next few years.
Site plan for permit is trow AM. Anything I should double check? Should be pretty straightforward with only panels being installed....thanks

[Wannaretireearly]

To comment further, the ones I added to the South east roof to the right (8 instead of 6) could be shaded by the left side of the home
The two I show on the south west roof in the middle could also get shade from the roof to its left

Yup. I think both these locations get some shading from the roofing above them...

[scrambler]

To comment further, the ones I added to the South east roof to the right (8 instead of 6) could be shaded by the left side of the home
The two I show on the south west roof in the middle could also get shade from the roof to its left