Two Powerwalls V2 not meeting expectations, why?

[Electric700]

Batteries are net power consumers.

If your Solar PV put out 50kWh on a good solar day, if you put them through batteries, the result is usable maybe 45kWh. you spend kWh by storing them. It's well know and sales should always be telling this. Batteries do not store the input electrons, they undergo a chemical reaction causing the electrons to move between Cathode and Anode. So, there are charging losses. Also, EVs undergo similar losses during charge. You may use 80kWh to charge a car and only be able to use 72kWh out of those.

If you charge batteries from the grid or solar PV all the time and they are used only for backup, you will spend a little money keeping them topped up, but not that much (they should not cycle much, they are Li-Ion and not Lead Acid which need topping up).

I think the only reason to use PowerWalls is if you really MUST have standby power and make sure you don't spend kWh doing so. And also if you are in CA and arbitraging the peak power load prices of a variable rate plan with super-peak prices in the afternoons.

Solar and batteries are a solution, but not an economic one.

Bonaire, with Powerwalls you can run off of the solar energy at night that you generated during the day, and if you produce enough solar energy, you can also shift power in the daytime during peak periods. In addition SolarInAZ mentioned he has a gas furnace. In the future he could get a heat pump and run everything off of an expanded solar array (or possibly wind power once Tesla adds that capability). This would further lower costs. If it were me I would see what I could do to keep the Powerwalls.

 

[miimura]

Thank you for that information. That's what I have come to believe as well.

What's a fair selling price for them, anybody? And I imagine I need a good solar electric company to come out to disconnect them, right?

If I can sell them, I want to get more panels.

You really need to look carefully at what your system is actually doing while it's running normally. The magnitude of the extra cost in your first post is really not logical. Go through the data presented in the Tesla app and take some notes and see what is actually happening. There's no way to know what the Powerwall system's contribution is just from your utility bill.

 

[SolarInAZ]

I have had them on the cost saving setting now, with the peak hours entered and reserving 50% of the batteries.

And my self-powered usage dropped from 57% to 15% for the last two days.

I'll let this play out for a week, but it doesn't look good.

 

[cwied]

Self-powered usage vs. cost savings are generally conflicting goals, so that's not unexpected. When you're trying to save costs, the goal is to use grid power when it's cheap and export power when it's expensive. This increases your total grid usage when compared to running in pure self-consumption mode.

What kind of credit do you get for exporting power? Is it a fixed rate or do you get the same rate as you would have paid at the time you export?

 

[MorrisonHiker]

Don't just look at the self-powered usage percentage. While it does show a value, it doesn't represent the whole picture. Most days, we charge our cars at 5 am via the grid (right after the Powerwalls stop powering the house). That makes it look like my self-powered percentage is in the single digits most mornings. Later in the day, I can produce two or three times as much as I will consume in a day, but the self-powered percentage can still be low if I don't consume directly from solar or the Powerwalls.

I used to run my Powerwalls on self-powered. Since they don't have a "scheduled self-powered" option to schedule when to power the house from the grid, I switched to balanced TBC. By altering the peak, part-peak and off-peak schedules, I can self-power my house for ~22 hours a day...but my self-powered percentage can still be low because so much of my consumption happens in that early in the morning when charging the cars.

 

[MorrisonHiker]

Don't just look at the self-powered usage percentage. While it does show a value, it doesn't represent the whole picture. Most days, we charge our cars at 5 am via the grid (right after the Powerwalls stop powering the house). That makes it look like my self-powered percentage is in the single digits most mornings. Later in the day, I can produce two or three times as much as I will consume in a day, but the self-powered percentage can still be low if I don't consume directly from solar or the Powerwalls.

I used to run my Powerwalls on self-powered. Since they don't have a "scheduled self-powered" option to schedule when to power the house from the grid, I switched to balanced TBC. By altering the peak, part-peak and off-peak schedules, I can self-power my house for ~22 hours a day...but my self-powered percentage can still be low because so much of my consumption happens in that early in the morning when charging the cars.

As an example, today my household usage was 49.5 kWh. I had the cars charge early and they took 32.3 kWh from the grid. That means my self-powered percentage for the day is only 35%: (49.5-32.3)/49.5

I produced 64.3 kWh and sent 44.7 kWh back to the grid. So while my self--powered percentage isn't that great today, I still produced 30% more than I consumed and sent 40% more back to the grid then I took from it.

So don't fret about self-powered percentage as it doesn't tell the whole story. I really wish they would calculate offset and other numbers which help explain the system's effectiveness better.

 

[smatthew]

I'd be interested in those power walls. 12cent/kw power at night is great for charging my car, but I wince every time I turn the oven on at 45cent/kw to make dinner.

 

[SolarInAZ]

I'd be interested in those power walls. 12cent/kw power at night is great for charging my car, but I wince every time I turn the oven on at 45cent/kw to make dinner.

Could the community suggest a fair price?

What other equipment would the buyer need to use them?

And, the big question, will the buyer be able to tie them to their account?

I might have to file something with the utility company as well, since I am changing the approved design, right?

 

[smatthew]

Could the community suggest a fair price?

What other equipment would the buyer need to use them?

And, the big question, will the buyer be able to tie them to their account?

I might have to file something with the utility company as well, since I am changing the approved design, right?

I could hazard a guess for the last three questions, but it might be best to reach out to the installation company (or another Tesla Powerwall approved electrician) and ask for a quote for removal.

 

[SoCalDude]

We just had a power outage and with my two Powerwalls, my house continued to operate as planned. No microwave clocks to reset, no problem with garage doors that wouldn’t open, and all appliances were available. I don’t mind the inefficiencies of the batteries for these benefits. The solar has a definite ROI. Batteries are more of an insurance policy that I hope I don’t need to use. But they are there for me on standby for any minor or major events.

 

[2012MS85]

@SolarInAZ Do you ever have power outages? Avoiding those via your PW2 is usually a key benefit. Even if historically you haven’t had many, long outages, the future could be different. You’d likely regret selling them in the future as you sat in the dark, without AC on a hot day

Your cost of installation and removal is a few thousand dollars. I’ve never seen anyone remove and sell a Powerwall used, so the fair market value is totally unknown. Would Tesla even support a buyer on the re-installation? They’re also quite heavy and hard to move. They also add re-sale value to your home. Finally, most folks are limited by their utility to approving a larger size solar system. I had to do mine in two phases, a year apart, because my utility would only allow me to generate a certain level based on my home’s historical usage. Once I started buying EVs and increasing my electricity demand, then they approved phase two. Lots of variables to consider. Good luck!

 

[2012MS85]

Another reason the resale value might be quite low is that many states like nearby CA have generous tax credits/rebates (added to the 30% federal tax credit) that make the net cost quite low for PW2.

FWIW, I think your PW2s look beautiful ...like all Tesla products!

 

[SolarInAZ]

@SolarInAZ Do you ever have power outages? Avoiding those via your PW2 is usually a key benefit. Even if historically you haven’t had many, long outages, the future could be different. You’d likely regret selling them in the future as you sat in the dark, without AC on a hot day

Your cost of installation and removal is a few thousand dollars. I’ve never seen anyone remove and sell a Powerwall used, so the fair market value is totally unknown. Would Tesla even support a buyer on the re-installation? They’re also quite heavy and hard to move. They also add re-sale value to your home. Finally, most folks are limited by their utility to approving a larger size solar system. I had to do mine in two phases, a year apart, because my utility would only allow me to generate a certain level based on my home’s historical usage. Once I started buying EVs and increasing my electricity demand, then they approved phase two. Lots of variables to consider. Good luck!

BTW - we cook with gas, as it's dirt cheap here, and my wife cooks and prefers it. Our goal is to just export as much energy as we can during the months we don't use AC and have a big enough credit to offset the summer. I am going to turn the money around into more solar panels and the highest seer AC unit I can. The number of power outages we get is very small, nearly as small as my perceived return on investment in powerwalls

After having gone down this path, if I had a history of power outages longer than a couple hours, I'd just buy a natural gas generator with auto-start/failover. They're only like $4000. They sit outside your house. They run on your natural gas lines. Carbon free? No. Effective? You could run on one perpetually.

Another reason the resale value might be quite low is that many states like nearby CA have generous tax credits/rebates (added to the 30% federal tax credit) that make the net cost quite low for PW2.

FWIW, I think your PW2s look beautiful ...like all Tesla products!

Are you sure about the tax credit on just buying batteries? It's not a solar panel, and it wouldn't qualify as a solar energy system, or am I missing something?

I did take a tax credit on my total system, which was some $38,500. But it was a solar energy system, not just power walls.

Since I flipped them back on, and set them for cost-savings, I am getting less credits from APS. I believe it's the energy overhead for charging them, not sure. I hate that the tesla app constantly shows energy going from the grid into the powerwalls.

 

[SolarInAZ]

So 11K for a pair is overpriced?

 

[SolarInAZ]

I think it's time to open a thread only asking for help. I have a screenshot that shows my dillemma.

 

[MorrisonHiker]

That send in line with the credits Tesla offered in the past for Powerwalls. However, there's no guarantee the Tesla would enable them for the new owner.

Before you sell them, I would see if Tesla could send a representative out to explain things to you. They would've analyzed your rate plans before installation so I'm sure they took your energy requirements into account and planned accordingly. It's also possible that some of the CT scan aren't configured properly so you think they are consuming more energy than they actually are out when they may be offering the house. If things are set up correctly, the Powerwalls will help save you money and provide backup if there is an outage.

We had three Powerwalls installed last year and will be adding more solar and another Powerwall this year. We are very pleased with their performance and the savings they have provided. Last fall when we first turned our new solar system on, our Powerwalls helped us avoid peak and part peak rates and cut our bills by 90%. Over the winter, the savings haven't been quite as high but have still allowed nearly all usage to be off peak. This summer, they will allow us to totally power the house during peak and send lots more energy back to the grid.

 

[SolarInAZ]

I posted another thread, requesting help, with a screenshot of what is happening.

Help analyzing Tesla Powerwall energy issues.

I am begining to think the installation was screwed up. They were in a rush.

 

[2012MS85]

[QUOTE="SolarInAZ, post: 3389001, member: 95567]
Are you sure about the tax credit on just buying batteries? It's not a solar panel, and it wouldn't qualify as a solar energy system, or am I missing something?

I did take a tax credit on my total system, which was some $38,500. But it was a solar energy system, not just power walls.[/QUOTE]

I didn’t mean to infer there are any tax credits for batteries alone; they’re almost always bought with solar panels as part of an averall system like yours (since that’s a requirement of the tax credit). If you sell them, and the IRS audited (rare/unlikely), you’d likely need to pay back the 30% credit, plus penalty and interest. Not judging or giving tax advice; just saying.

Bottom line is Tesla likely split out your install as $25,500 for solar panels (8.5 kw @ $3 per watt) plus $13,000 for batteries (2 x $5,500 retail PW2, plus $2,000 for hardware/installation). So what I’m trying to extrapolate is the limited value of two used PW2s that have no tax credit value and still must incur significant costs for professional removal, transportation, re-installation and then possibly limited support/warranty from Tesla with the 2nd owner.

Just curious, what are APS’s peak vs off-peak rates? When I stayed in Phoenix with friends who live there, I thought they said they paid only 6-7 cents per kWh for electricity. That was a couple years ago.

 

[SolarInAZ]

[QUOTE="SolarInAZ, post: 3389001, member: 95567]
Are you sure about the tax credit on just buying batteries? It's not a solar panel, and it wouldn't qualify as a solar energy system, or am I missing something?

I did take a tax credit on my total system, which was some $38,500. But it was a solar energy system, not just power walls.

I didn’t mean to infer there are any tax credits for batteries alone; they’re almost always bought with solar panels as part of an averall system like yours (since that’s a requirement of the tax credit). If you sell them, and the IRS audited (rare/unlikely), you’d likely need to pay back the 30% credit, plus penalty and interest. Not judging or giving tax advice; just saying.

Bottom line is Tesla likely split out your install as $25,500 for solar panels (8.5 kw @ $3 per watt) plus $13,000 for batteries (2 x $5,500 retail PW2, plus $2,000 for hardware/installation). So what I’m trying to extrapolate is the limited value of two used PW2s that have no tax credit value and still must incur significant costs for professional removal, transportation, re-installation and then possibly limited support/warranty from Tesla with the 2nd owner.

Just curious, what are APS’s peak vs off-peak rates? When I stayed in Phoenix with friends who live there, I thought they said they paid only 6-7 cents per kWh for electricity. That was a couple years ago.[/QUOTE]

Well first off, I think they're actually wired wrong but that's in another thread.

There is no requirement to keep anything you purchase and receive a deduction for. Just like if I sold the house.. no requirement to give the money back to the IRS.

APS averaged out my cost as $185 per year; it was adjusted after I lived here the first year, and I was on the adjusted billing (offsetting summer costs into the winter).. Otherwise I would have had $400 per month in the summer. I am not in phoenix, I am some 125 miles away.

Anyway I doubt you can just buy powerwalls and take a tax credit; you would need them to be purchased as part of a solar energy package. I paid $14000 for the powerwalls plus installation. I think the current price is more like $7000, not $5500.

But as I said above, if they're wired wrong, then no wonder I am not getting what I expected. Let's wait to see what happens next.

The other thread is linked above.

 

[SolarInAZ]

Whoops last piece:

I talked to Tesla, and not only can I sell them, the full warranty can be transferred to the new owner. The only caveat is they would need to be installed by an approved installer.

But if they're just wired wrong, of course I wouldn't sell them. I only considered selling them because they are not working as expected.