PowerShare vs Powerwall questions

[Woodrick]

It was over 90F today. I live in the mountains, not the city, of Santa Cruz. It was 70F on the beach.

When you install a Powerwall, the circuits it's protecting are selected then. It's not just plugged into a whole house unless the house draws less than the output. And I don't know about your house, but mine can't draw 9.6kW of power, let alone continuously.

Even AC doesn't use power continuously. The fans and pumps cycle on and off. And thermal dynamics being what they are, it's best to design a house to have a thermal mass so it doesn't need constant, emergency heating and cooling.

It's all about balancing that.

And I say that as now, the power is out, and has been for an hour and a half, and I'm on battery, and PG&E says the power won't be on for another two hours. The house isn't going to suddenly heat up because it's placed in the shadow of the trees, and I cooled it down last night to have the thermal mass to make it through the day.

The vast majority of houses will do just fine on a Powerwall. Especially one that has its own island of solar panels to back it up, and that means Powershare is only for when things get dire and so it doesn't need to be so 'automatic' other than having it plugged in.

-Crissa

And you are absolutely correct.
But go back and read the first post. At what point did anything get said about having to move loads around?

And no, AC doesn't necessarily use power continuously. But on hot days with a zoned system, mine has been known to. And definitely on cold nights (it's a heat pump) and the supplemental strips engaged, it definitely can stay on 12+ hours.

Everyone is different. Any use of Powerwall or Powershare should be evaluated by a professional.
Not a few posts on an Internet forum!

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[Woodrick]

How much energy someone's home uses at night is entirely based on their own circumstances. However, a PW has ~13kWh of power. CT can provide a variable amount of it's capacity for PS to supplement PW. Say, for discussion purposes you allocate 70% to PS = 84 kWh. 84+13=97 kWh total available for backup power via PS + PW. I would find it hard to believe any normal single family residential home would use that much power overnight.

I believe that I'm over 150kWh per day.
And yes, it is a single-family home, and it's larger than 4,000 sqft.

But you know what, you may find that the early adopters of the Cybertruck may have slightly higher incomes and larger houses.

 

[deltaflyboy]

I believe that I'm over 150kWh per day.
And yes, it is a single-family home, and it's larger than 4,000 sqft.

But you know what, you may find that the early adopters of the Cybertruck may have slightly higher incomes and larger houses.

Wow you must be charging your cars a lot during the day. I have a pretty large house 2 AC units, pool pump and boat plugged in and average about 70KW/day

The EVs are the big draw could be more than twice the house draw if fully charging

I have a solar system (about 120KWH/day) with 3 PWs and easily produce enough power to run entire house all day through solar and at night through PWs.

If you add in the car charging its a much different story.

 

[Crissa]

The average home uses less than 30kWh in a day.

And the cost of running a generator backup should be examined - even at it's most efficient lowest price, the fuel alone will cost more per kWh than my peak grid rate (let alone you guys'). So my batteries continue to get cheaper over time, the more I use them.

...and I just had to use the yesterday, when I posted to this thread, because some idiot went off the road in my neighborhood and hit a power pole. That's another five hours to throw on the pile dividing the capital cost of those batteries.

-Crissa

 

[yrekabaker]

PW is 13.5 KWHr. Looking at my bills from before I got the Tesla, I used 30-40 kwHr a day. So I would think that 13.5 kwHr would go a long way.

Or are you talking about generating enough excess solar to be able to charge the PW?

Or are you talking about those that have a system not set up to charge battery from the grid? I think that is part of some AHJ's net metering contracts. Don't really understand that, but I think there are ways around it.

A 13.5 kWh battery will only support your house for a few hours in a grid outage. PS will work for 2-3 days. i have PS. It works very well and can be recharged in an hour or two if it runs down. I am not dissing PW but PS does do some good things.

 

[Crissa]

A 13.5 kWh battery will only support your house for a few hours in a grid outage. PS will work for 2-3 days. i have PS. It works very well and can be recharged in an hour or two if it runs down. I am not dissing PW but PS does do some good things.

Powerwall can handle a higher peak and can also bank with others to provide a higher output than Power Share. Power Share also has a slower switchover time. Power Share's advantage is the deep well of battery, which makes it last so long.

Also, if you have a Powerwall, and your Wall Connector is wired behind it, you have the advantage of both.

So really it's not choosing Power Share or Powerwall - it's choosing only Power Share or both Powerwall and Power Share.

-Crissa

 

[PES_CT]

I just finished a PowerShare install by Smart Charge America. We have about 16kW of solar on our roof that uses microinverters to supply power to the grid, but shut off for safety reasons whenever we lose power. We don't have a backup system so that was one of my main reasons for purchasing the Foundation Series, but only if my solar could work concurrently. I was told by Smart Charge America that PowerShare will work like a giant Powerwall and that Tesla plans to have it operate with my type of solar panels, although probably not until 3rd or 4th quarter 2024.

Smart Charge America left before the system would actually connect to the truck. They thought that a minor truck software update would fix the problem so left while it was being installed - it didn't. It took 2.5 hours on the phone with Tesla correcting errors impossible for a homeowner to fix, but they were also able to confirm that Tesla employees who bought CT's are testing solar with the PowerShare. I'm curious what others have heard.

 

[Woodrick]

Wow you must be charging your cars a lot during the day. I have a pretty large house 2 AC units, pool pump and boat plugged in and average about 70KW/day

The EVs are the big draw could be more than twice the house draw if fully charging

I have a solar system (about 120KWH/day) with 3 PWs and easily produce enough power to run entire house all day through solar and at night through PWs.

If you add in the car charging its a much different story.

Not charging much at all. Probably average 50 miles a day.

I had someone over to quote some PV a few years ago. Their response was that my Utility provider only really supported up to 20kW worth of cells, so all I could do is augment, my usage.

My point is that everyone is different, you can't really make blanket statements.

And my electric bill is lower than many gas bills in the Northeast!

 

[Crissa]

You need to sue your utility, then, Woodrick. They're lying.

-Crissa

 

[Cyberus]

A 13.5 kWh battery will only support your house for a few hours in a grid outage. PS will work for 2-3 days. i have PS. It works very well and can be recharged in an hour or two if it runs down. I am not dissing PW but PS does do some good things.

Thanks for your comments.

This would be ideal for me. I plan to use the PW during peak hours only, and PS only when necessary. I think this is the best solution for my use case. And 6500 to install only the PS doesn’t make sense if I can get a PW with installation for a few thousand more, and it allows for PS from the CT. Which means that if I decide in the future that the CT is no longer for me, I don’t have equipment that is useless to me that I paid for, and I still have the PW.

I hope this helps others who are in a similar situation.

 

[Woodrick]

You need to sue your utility, then, Woodrick. They're lying.

-Crissa

Why do you think so?
I'm an Electrical Engineer. I am quite knowledgeable on power items.
I've got a wall worth of equipment on the other side of my office that pulls 500 watts, constantly. That alone is 12kW/day. I suspect that my data center rack is doing nearly the same, let's say only 10kW, for a total of 22kW/day.
And then there's the rest of the house.

And why do you think my utility is lying?

 

[CyberGus]

A nice benefit of Powershare is that the 3V Gateway shows your power usage.

The sawtooth is my air-conditioning cycling, the big splke is my truck charging lol

 

[Crissa]

Why do you think so?
I'm an Electrical Engineer. I am quite knowledgeable on power items.
I've got a wall worth of equipment on the other side of my office that pulls 500 watts, constantly. That alone is 12kW/day. I suspect that my data center rack is doing nearly the same, let's say only 10kW, for a total of 22kW/day.
And then there's the rest of the house.

And why do you think my utility is lying?

You seem bad at this engineering thing.

And yes, they should only affect what you export to the grid.

They have no control of any equipment that doesn't. If you have something with a constant draw, and places to put solar, that screams to buffer it with like an Ecoflow which can absorb solar.

They also can't tell you not to use solar to heat a thermal battery or mass to shift your usage, either.

-Crissa

 

[Woodrick]

You seem bad at this engineering thing.

And yes, they should only affect what you export to the grid.

They have no control of any equipment that doesn't. If you have something with a constant draw, and places to put solar, that screams to buffer it with like an Ecoflow which can absorb solar.

They also can't tell you not to use solar to heat a thermal battery or mass to shift your usage, either.

-Crissa

So give me the numbers. Show me your engineering.

 

[Crissa]

So give me the numbers. Show me your engineering.

What numbers?

Instead of complaining, actually do things. How does encouraging you to act against your local utility being monopolistic need numbers?

-Criss

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