Solar Panels for the house

[Dahobbs 17572]

12 minutes ago, fattyflattie said:

Your 10 year timeline at 3%.   The last ~18 months have been considerably higher, up to twice that.    So, nearly 20% of your example payback period (10 years) doesn’t track at all with 3%.  Would be akin to me mentioning do it on a HELOC at 2.375 because that’s what we did 18 months ago. Similar to 3% inflation, that’s not the # anymore. 

Yes, inflation for energy prices has been higher the last few years. But I wouldn't use that outlier period in making any longer term financial decisions. If energy inflation continues at that pace, obviously the payback period would be much shorter. 

[fattyflattie 4639]

58 minutes ago, Dahobbs said:

Yes, inflation for energy prices has been higher the last few years. But I wouldn't use that outlier period in making any longer term financial decisions. If energy inflation continues at that pace, obviously the payback period would be much shorter. 

Agreed. It’s going to fluctuate. Not sure how many more times we’ll get back into the .07 range like a few years ago.  If I ever get a new roof, and it looks like we’re going to stay in this house, I’ll be on it. 

[Doc Daneeka 6769]

56 minutes ago, fattyflattie said:

Agreed. It’s going to fluctuate. Not sure how many more times we’ll get back into the .07 range like a few years ago.  If I ever get a new roof, and it looks like we’re going to stay in this house, I’ll be on it. 

That’s where I am. My roof is relatively new, though. Inflation is the wildcard in calculating payback, imo. 

I’d be on board with filling my roof as much as is reasonable and throwing in some batteries, understanding that the batteries may be more convenience than anything. I just don’t want to pay an outrageous premium to do it. 

I’m not proposing this policy, but if this approach is really a factor in preventing climate Armageddon, make it more feasible. Hell, at least make the credit refundable. (If it is and I’m wrong, that would be good to know).

[Doc Daneeka 6769]

23 hours ago, Dahobbs said:

But, being in Fort Worth with a big south facing roof, there isn't any reason you couldn't get a system that would pay for itself in 7 years.

Tesla’s site (1 Powerwall) estimates my net savings over 25 years as $11.5K. $9.6K of that is the tax credit. About $6.33 a month if all their estimates work out. Off the top of my head, that’s about 1/10 of what the net cost ($22,238) would earn sitting in a savings account. 

If my electricity bill were twice as high, they said it would be a wash outside of the tax credit for 25 years  

sigh  

 

[Dahobbs 17572]

29 minutes ago, Doc Daneeka said:

Tesla’s site (1 Powerwall) estimates my net savings over 25 years as $11.5K. $9.6K of that is the tax credit. About $6.33 a month if all their estimates work out. Off the top of my head, that’s about 1/10 of what the net cost ($22,238) would earn sitting in a savings account. 

If my electricity bill were twice as high, they said it would be a wash outside of the tax credit for 25 years  

sigh  

 

Powerwall is going to completely throw off those estimates as it doesn't get you an additional return on investment besides the security of having a backup and its like half of your total price.

[Doc Daneeka 6769]

Just now, Dahobbs said:

Powerwall is going to completely throw off those estimates as it doesn't get you an additional return on investment besides the security of having a backup and its like half of your total price.

I get that. Take it out and double my net savings. 

[troph 24810]

41 minutes ago, Dahobbs said:

Powerwall is going to completely throw off those estimates as it doesn't get you an additional return on investment besides the security of having a backup and its like half of your total price.

and you have to have enough solar to feed the house and the battery during the day. so you have to over power a bit.  and one powerwall bottle necks at 30 amps of power output at any given time. that's not a lot, and it means you need to charge your car, dry your clothes, etc. during the day. HVAC and electric appliances while cooking could hit that 30 amps hard I would think causing a breaker to trip if the grid isn't available and drawing on the grid when you have plenty of battery power when the grid is available (neither of those situations are desirable for us).  we are at 60 amps max power at any given time with two powerwalls, and we are trying to charge the car and use the dryer and run the pool pump during the day while saving HVAC and cooking for the evening on battery power along with lights and TV, etc.

basically powerwalls are expensive, require additional solar panels to generate the power to store the energy, inflate your install cost by nearly 100% and they have significant restrictions in what they can and can't do.  they are still an elegant solution, but I think you have to be ok with investing in your comfort and be dedicated to the green part of the whole equation.  if you are just doing it to save a few bucks on your electricity bill I don't know of a scenario where the math works out well.

Edited February 23, 2023 by troph

[HOOKEM4 5037]

17 hours ago, Amos Moses said:

I guess this means you’re not going to sell your Airstream to me?

Haha. It actually got sold to an extended family member. I forgot to message you back.

 

Edited February 23, 2023 by HOOKEM4

[Doc Daneeka 6769]

9 minutes ago, troph said:

could hit that 30 amps hard I would think causing a breaker to trip

I’m pretty ignorant on this, so this is likely to be a stupid question, but which breaker are you talking about here? On the Powerwall?

If so, presumably, this would switch you over to using the grid? Does this look like a power outage to your house? Is there a physical breaker to reset to get back on the Powerwall?

If a different breaker, which… the “regular” breakers that your appliances would trip?

Thanks. 

Edited February 23, 2023 by Doc Daneeka

[troph 24810]

8 minutes ago, Doc Daneeka said:

I’m pretty ignorant on this, so this is likely to be a stupid question, but which breaker are you talking about here? On the Powerwall?

If so, presumably, this would switch you over to using the grid? Does this look like a power outage to your house? Is there a physical breaker to reset to get back on the Powerwall?

If a different breaker, which?

Thanks. 

edit:  this is for a grid down situation where batteries are your only power source.

breakers on your electric panel, when your home is asking for more power than comes through from the battery, a breaker will trip as a safety feature to rebalance down to the 30 amp draw (30 per powerwall).  it would act like a power outage for that electrical circuit. it could flip the whole house I guess, I'm not an electrician but if you demand more power than you receive, breaker(s) will trip. 

any time you are looking for a backup power solution you are going to have to invest real dollars without a return and the more you want to emulate full power like from the grid, the more you'll have to spend, that's the takeaway.  goes for batteries, natural gas generators, any solution really.

Edited February 23, 2023 by troph

[Doc Daneeka 6769]

Just now, troph said:

breakers on your electric panel, when your home is asking for more power than comes through from the battery, a breaker will trip as a safety feature to rebalance down to the 30 amp draw (30 per powerwall).

Oof. That makes sense, I suppose, but I guess in the back of my mind I kind of low-key expected the system automagically to start pulling from the grid (if available) rather than flipping breakers. 

[troph 24810]

5 minutes ago, Doc Daneeka said:

Oof. That makes sense, I suppose, but I guess in the back of my mind I kind of low-key expected the system automagically to start pulling from the grid (if available) rather than flipping breakers. 

I'm talking in a down grid situation, sorry.  I probably was confusing to everyone.

if the grid is going, yes it will mix sources from the grid and the battery if you exceed 30 amps per (or run your battery down).

if the grid is down, no, you are stuck with that limitation of 30 amps per and it will flip a breaker.

if you want to avoid pulling grid power when the grid is available, you have to watch your amps, but you won't flip a breaker, you'll just pull from the grid when you don't want to. 

I made appropriate edits to the posts above to be clear. sorry i'm still new here too.

Edited February 23, 2023 by troph

[Doc Daneeka 6769]

Just now, troph said:

I'm talking in a down grid situation, sorry.  I probably was confusing to everyone.

if the grid is going, yes it will mix sources from the grid and the battery.

if the grid is down, no, you are stuck with that limitation of 30 amps per.

if you want to avoid pulling grid power when the grid is available, you have to watch your amps, but you won't flip a breaker, you'll just pull from the grid.

sorry i'm still new here too.

Nah, no need to apologize. I’m trying to learn and you’re helping. 

The on-grid mixing is exactly what I would expect as is the off-grid “throttling.” That explanation makes perfect sense. Or at least it aligns with what I expected, which I usually think is the same thing. 

[troph 24810]

37 minutes ago, Doc Daneeka said:

Nah, no need to apologize. I’m trying to learn and you’re helping. 

The on-grid mixing is exactly what I would expect as is the off-grid “throttling.” That explanation makes perfect sense. Or at least it aligns with what I expected, which I usually think is the same thing. 

I'm just saying a $12K product with a $2-4K install price tag for $14-16K all in cost (before any rebates) is a hefty price for 30 amps of max power regardless of the consequence of exceeding 30 amps (pull from the grid or flip a breaker), especially when you then have to make sure you have the panels to feed it.  and this is coming from someone that loves the product and the solution.

Edited February 23, 2023 by troph

[HouTex 1878]

I haven’t read the entire thread, but I’m curious in how the $14-16k number is calculated.  I have a 3,900 square feet patio home and my usage peaked last year in July at around 2,500 kWH for the month.  That bill was about $292.  I want power back up and I don’t have the room on my property for a Generac.  I called Tesla a few months ago and they quoted me around $88,000 for a system, including batteries, that would power my house for a couple of days after a grid outage depending on sunlight.  I said no thanks.  I’m guessing the batteries will come down in price over the next few years and I might revisit a solar solution. 

[troph 24810]

15 minutes ago, HouTex said:

I haven’t read the entire thread, but I’m curious in how the $14-16k number is calculated.  I have a 3,900 square feet patio home and my usage peaked last year in July at around 2,500 kWH for the month.  That bill was about $292.  I want power back up and I don’t have the room on my property for a Generac.  I called Tesla a few months ago and they quoted me around $88,000 for a system, including batteries, that would power my house for a couple of days after a grid outage depending on sunlight.  I said no thanks.  I’m guessing the batteries will come down in price over the next few years and I might revisit a solar solution. 

listed price for a single powerwall battery is about $12K, install of that powerwall is several grand over that.  additional work may be required as well. But that does not include any solar panels or basic electrical work required to install a full system.  we have 2 powerwalls and 16kWh solar - enough for day use and power the two batteries.  We went with a different provider than tesla but your quoted price isn't far from what 16kWh + 2 powerwalls + misc equipment required + install would cost.  I was only breaking out the cost of the powerwall as a line item when I said $14-16K.

[Dahobbs 17572]

2 hours ago, HouTex said:

I haven’t read the entire thread, but I’m curious in how the $14-16k number is calculated.  I have a 3,900 square feet patio home and my usage peaked last year in July at around 2,500 kWH for the month.  That bill was about $292.  I want power back up and I don’t have the room on my property for a Generac.  I called Tesla a few months ago and they quoted me around $88,000 for a system, including batteries, that would power my house for a couple of days after a grid outage depending on sunlight.  I said no thanks.  I’m guessing the batteries will come down in price over the next few years and I might revisit a solar solution. 

Keep in mind, with sunlight, that system would likely be self-sufficient indefinitely so long as you cut back on electricity a little bit (e.g., not running a drier, electric oven, or charging an electric car). 2500 kWH as your peak isn't that high frankly. Last july my 1,300 sq ft house used a little bit less than that at 2,400 kwh (with two electric vehicles). But, yes, batteries are luxury item right now. Prices may come down... or they may not since demand is also increasing. 

[HouTex 1878]

18 minutes ago, Dahobbs said:

Keep in mind, with sunlight, that system would likely be self-sufficient indefinitely so long as you cut back on electricity a little bit (e.g., not running a drier, electric oven, or charging an electric car). 2500 kWH as your peak isn't that high frankly. Last july my 1,300 sq ft house used a little bit less than that at 2,400 kwh (with two electric vehicles). But, yes, batteries are luxury item right now. Prices may come down... or they may not since demand is also increasing. 

My expectation is that it would be self sufficient.  It’s the price tag that shocked me.  

[High Plains Drifter 11050]

 

I already have the solar panels installed, anybody have any ball park figures how much it would be to add a battery back up system? I'd rather go that route than a gas generator (no maintenance being one reason).

[Gil Bang 25961]

21 hours ago, DalTxHornFan said:

IDK, but these guys may sneak up on your power usage.

 

21 hours ago, troph said:

I actually have one of those.  

Yeah, there might be one of those in the nightstand, and I "might" keep it charged, just in case the power goes out. 

Good battery life on that product.  She runs out of energy before the device does. 

[fattyflattie 4639]

35 minutes ago, High Plains Drifter said:

 

I already have the solar panels installed, anybody have any ball park figures how much it would be to add a battery back up system? I'd rather go that route than a gas generator (no maintenance being one reason).

A few posts up says 12-14k plus a few for install. 

[Dahobbs 17572]

24 minutes ago, fattyflattie said:

A few posts up says 12-14k plus a few for install. 

You get a discount if you get more than one. However, right now Tesla will only sell them if you also get panels. You may be able to find them available with some installers. Competing products also exist (see Enphase) that are getting better. Not sure on prices. 

[High Plains Drifter 11050]

 

so the tesla "powerwall" is the battery back up?

Apparently I'm out of luck on that as I already have the panels.

 

Looking at enphase, and it also assumes I don't already have the panels. furk. I'll guess I'll have to actually "speak to a representative".

[Dahobbs 17572]

31 minutes ago, High Plains Drifter said:

 

so the tesla "powerwall" is the battery back up?

Apparently I'm out of luck on that as I already have the panels.

 

Looking at enphase, and it also assumes I don't already have the panels. furk. I'll guess I'll have to actually "speak to a representative".

Yes, power wall is the battery. You can sometimes get batteries from the installers if they have them in stock. So you might check around your local solar installers. 

[High Plains Drifter 11050]

15 minutes ago, Dahobbs said:

Yes, power wall is the battery. You can sometimes get batteries from the installers if they have them in stock. So you might check around your local solar installers. 

 

Yeah, I'll contact the guy who installed my system years ago. I heard through the grapevine that he got the cancer, so I'm not even sure he is still in the biz. I might be out of luck, I'm kind out in the middle of nowhere, finding a contractor for anything is a pita.

Thanks.

[troph 24810]

17 hours ago, Gil Bang said:

 

Yeah, there might be one of those in the nightstand, and I "might" keep it charged, just in case the power goes out. 

Good battery life on that product.  She runs out of energy before the device does. 

the plug-in version is on a whole other level.

[Party_Taco 3734]

Pinging this thread as well - Did anyone get a Powerwall installed recently? Looking for comps on install costs, if available. Thanks!