Help understanding solar/powerwall 3/powershare

[Awinsagain]

Hi All,

I have a foundation CT and currently have no solar or PW. I was planning on installing powershare until the quote from the Tesla sub came in at $8,000-$9,000! For that, I could simply grab a PW for a bit more and have way better of a situation.

I am now currently exploring solar + PW. BC I have the CT, I am thinking I just need 1 PW3 to help with the initial start during an outage for the first 3-6 hours and then use my CT as backup after that for another 6-24 hours or however long it can last.

Our home is 3500 ft in the sf bay area. Thoughts on this approach? Is there any reason I would need 2 PW3? Besides adding a soft start to AC, will the CT as backup have any downsides when it kicks in if my PW3 drains?

Thanks all! Any feedback is appreciated and so are tips on which equipment I need to ensure is getting installed so the CT can backup the house!

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[JohnnyDadBod]

Install costs for Pw3 will be nearly the same as installing PowerShare. You go through the same permitting process and have to install the same Tesla Gateway (though there is some consolidation of hardware built into PW3)

what you are expressing in the second paragraph is basically my plan. I already have Tesla Solar but no Power Wall. I am loooing to have one PW3 installed and then I’ll add capacity via PowerShare. I am waiting quotes now from the PowerShare request. Added benefit with this route is that all the install costs plus the cost of Pw3 will qualify for the 30% federal tax rebate.

 

[Awinsagain]

Thanks for the reply. Yeah exactly similar situation. That’s why I figured why drop 8-9k for PowerShare only when 15ish gets me all the benefits of power wall (like peak cycling, instant turn on, high amount of continuous output)

Can installers get the new gateway needed for PowerShare? I went online to see if I could buy with my 2500 credit and appears can’t be sold to me and only to their sub?

 

[Dmitrij]

Keep in mind that PowerShare is backup for backup option. CT battery is 10 times more than PW capacity. But if you want seamless backup power (uninterrupted) go and get PW with solar panels. As much as you can afford. 2-3 would be great but even 1 PW will help with short outages. Evaluate how many power outages you have had for the last 10 years and for how long and you will figure out how many PWs you need.

 

[Awinsagain]

Keep in mind that PowerShare is backup for backup option. CT battery is 10 times more than PW capacity. But if you want seamless backup power (uninterrupted) go and get PW with solar panels. As much as you can afford. 2-3 would be great but even 1 PW will help with short outages. Evaluate how many power outages you have had for the last 10 years and for how long and you will figure out how many PWs you need.

This is great feedback, thanks. Our outages are usually not that long but in 2023, we had perhaps around 12-15 outages the average being 2-3 hours (With the longest maybe being around 8).

My thought is 1 PW will let us cycle during peak power (5-9pm) to avoid those PG&E utility rates, provide seamless back up for 70% of the outages, and then in a dire situation where we have a 6+ hour outage, I can use the CT when the PW is drained (assuming PW is not being recharged by sun)

 

[Dmitrij]

My thought is 1 PW will let us cycle during peak power (5-9pm) to avoid those PG&E utility rates, provide seamless back up for 70% of the outages, and then in a dire situation where we have a 6+ hour outage, I can use the CT when the PW is drained (assuming PW is not being recharged by sun)

Yeah, that’s another point to consider! Definitely you can set up your PW to feed the house during peak time to reduce your bill. PowerShare won’t give you that option.

 

[Dmitrij]

Here is my setup:

• 15.2 kW system with a single Powerwall+
• 2,100 sq ft house with a single AC unit
• Located in Orlando, FL, with an average of 5.4 peak sunlight hours per day

This setup covers all house needs plus charging for my Model Y. Excess generated energy is exported to the grid, which essentially leverages night use. You can see the monthly consumption in the attached picture. The last two months (May-June) showed a spike due to the Cybertruck purchase.
If I were installing my solar+PW system today I’d install 2 PWs. The solar part was sized fine.

 

[Awinsagain]

Here is my setup:

• 15.2 kW system with a single Powerwall+
• 2,100 sq ft house with a single AC unit
• Located in Orlando, FL, with an average of 5.4 peak sunlight hours per day

This setup covers all house needs plus charging for my Model Y. Excess generated energy is exported to the grid, which essentially leverages night use. You can see the monthly consumption in the attached picture. The last two months (May-June) showed a spike due to the Cybertruck purchase.
If I were installing my solar+PW system today I’d install 2 PWs. The solar part was sized fine.

Awesome feedback. Do you plan on using the CT for backup in cases where that was/is needed and you somehow go through your only power wall during an outage?

 

[Dmitrij]

Awesome feedback. Do you plan on using the CT for backup in cases where that was/is needed and you somehow go through your only power wall during an outage?

Last year, we had a blackout lasting about 24 hours after the hurricane. It was the first real-life test for the system, and it passed. We had power until the lines were fixed. Of course, the AC was hooked up to a non-backed-up panel. So, without AC use, the Powerwall did its job perfectly.

I plan to use the Cybertruck for more extended outages. I believe, with limited use, it can power the house for about 10 days or so.

 

[flyinglow]

Hi All,

I have a foundation CT and currently have no solar or PW. I was planning on installing powershare until the quote from the Tesla sub came in at $8,000-$9,000! For that, I could simply grab a PW for a bit more and have way better of a situation.

I am now currently exploring solar + PW. BC I have the CT, I am thinking I just need 1 PW3 to help with the initial start during an outage for the first 3-6 hours and then use my CT as backup after that for another 6-24 hours or however long it can last.

Our home is 3500 ft in the sf bay area. Thoughts on this approach? Is there any reason I would need 2 PW3? Besides adding a soft start to AC, will the CT as backup have any downsides when it kicks in if my PW3 drains?

Thanks all! Any feedback is appreciated and so are tips on which equipment I need to ensure is getting installed so the CT can backup the house!

If you are trying to backup your home, the issue that might have caused the high quote could have been been that, with only 11.5 kW, Powershare would require that the installer isolate only the critical circuits that amount of power will support according to the electrical code. The installer would have to change your panel or add a subpanel. Also, if you are installing Powershare without a PW, you need additional devices (the Gateway and Universal Wall Connector). This adds up.

FYI, the same is true if you only have a single PW as it is also limited to 11.5 kW but it doesn't need the Gateway (which is an automatic transfer switch to isolate your power from the grid in an outage so the utility workers are safe).

What I am not clear on at this point is if you have a PW and a CT with Powershare, do they add up to a total 23 kW? If so, you most likely would not need to isolate circuits on a subpanel. Or, does the inverter in the PW limit the total to 11.5 kW in which case you still need multiple PWs or a subpanel? Does someone have info on this?

A lot of this depends on the electrical loads your house has. If almost everything is natural gas or propane your total electrical loads are small vs an all electric home.

I have long delayed adding a backup battery to my home because I would have needed multiple batteries because my critical loads (heat pumps and water pumps) are to large for single batteries. The EV truck provides, potentially, a more cost effective and more practical solution.

 

[mongo]

What I am not clear on at this point is if you have a PW and a CT with Powershare, do they add up to a total 23 kW? If so, you most likely would not need to isolate circuits on a subpanel. Or, does the inverter in the PW limit the total to 11.5 kW in which case you still need multiple PWs or a subpanel? Does someone have info on this?

They should combine to 23kW. However, Tesla has not released PW compatible SW software yet.
It also doesn't help in the event that the truck isn't plugged in during an outage.

 

[Woodrick]

Hi All,

I have a foundation CT and currently have no solar or PW. I was planning on installing powershare until the quote from the Tesla sub came in at $8,000-$9,000! For that, I could simply grab a PW for a bit more and have way better of a situation.

I am now currently exploring solar + PW. BC I have the CT, I am thinking I just need 1 PW3 to help with the initial start during an outage for the first 3-6 hours and then use my CT as backup after that for another 6-24 hours or however long it can last.

Our home is 3500 ft in the sf bay area. Thoughts on this approach? Is there any reason I would need 2 PW3? Besides adding a soft start to AC, will the CT as backup have any downsides when it kicks in if my PW3 drains?

Thanks all! Any feedback is appreciated and so are tips on which equipment I need to ensure is getting installed so the CT can backup the house!

The solutions seldom add up the way that most people think that they do.
One Powerwall is generally only good for a limited time of a limited number of circuits.
Powershare will handle a similar number of circuits, but do so for a longer time.

What did your contractor specify?

Are you willing to live in the heat of the summer bay without A/C?

 

[Awinsagain]

If you are trying to backup your home, the issue that might have caused the high quote could have been been that, with only 11.5 kW, Powershare would require that the installer isolate only the critical circuits that amount of power will support according to the electrical code. The installer would have to change your panel or add a subpanel. Also, if you are installing Powershare without a PW, you need additional devices (the Gateway and Universal Wall Connector). This adds up.

FYI, the same is true if you only have a single PW as it is also limited to 11.5 kW but it doesn't need the Gateway (which is an automatic transfer switch to isolate your power from the grid in an outage so the utility workers are safe).

What I am not clear on at this point is if you have a PW and a CT with Powershare, do they add up to a total 23 kW? If so, you most likely would not need to isolate circuits on a subpanel. Or, does the inverter in the PW limit the total to 11.5 kW in which case you still need multiple PWs or a subpanel? Does someone have info on this?

A lot of this depends on the electrical loads your house has. If almost everything is natural gas or propane your total electrical loads are small vs an all electric home.

I have long delayed adding a backup battery to my home because I would have needed multiple batteries because my critical loads (heat pumps and water pumps) are to large for single batteries. The EV truck provides, potentially, a more cost effective and more practical solution.

Thanks for your reply. This type of stuff is getting me stuck up too. I am very much a newbie on this. For example, learning that with 1 PW3 + cybertruck, I may not have enough output to run seamlessly in an outage BUT will have a crap ton of capacity bc the truck.

I am going to start my setup off with solar, 1 PW3, and my CT. If it ends up becoming that we require a 2nd PW3 to power more things during a blackout, then so be it. But our goal during an outage is to be minimal with electrical use (besides running AC if hot)

 

[flyinglow]

Thanks for your reply. This type of stuff is getting me stuck up too. I am very much a newbie on this. For example, learning that with 1 PW3 + cybertruck, I may not have enough output to run seamlessly in an outage BUT will have a crap ton of capacity bc the truck.

I am going to start my setup off with solar, 1 PW3, and my CT. If it ends up becoming that we require a 2nd PW3 to power more things during a blackout, then so be it. But our goal during an outage is to be minimal with electrical use (besides running AC if hot)

I sympathize. Most of the information we get is superficial and fuzzy on details. The installers get training that covers the intricate details so it can be best to talk to one of them and have them explain just what you need and why.

I sold/designed solar for over a decade and, not being an electrical engineer, can still find myself scratching my head in puzzlement. Different sources of energy (wind, solar, water, battery, ICE generators) feed your home in different ways with different equipment and they don't usually integrate together well. I have a propane generator large enough to power the home and charge a couple of vehicles. I am still waiting for/hoping for a system (come on Enphase!) that can use my solar, the vehicle's battery and the generator as needed/available for backup as well as let me sell the battery power to the utility to make money off them (and give them the middle finger) when grid connected.

 

[Awinsagain]

Thanks for your reply. This type of stuff is getting me stuck up too. I am very much a newbie on this. For example, learning that with 1 PW3 + cybertruck, I may not have enough output to run seamlessly in an outage BUT will have a crap ton of capacity bc the truck.

I am going to start my setup off with solar, 1 PW3, and my CT. If it ends up becoming that we require a 2nd PW3 to power more things during a blackout, then so be it. But our goal during an outage is to be minimal with electrical use (besides running AC if hot)

Will you be doing a power wall 3 and not 2?

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