NorCal, Tesla 4kw + 1 powerwall

[J.P.M.]

Thanks Richard and JPM! Good questions for me to ask the vendors, max system production vs. Avg expected system production...

As a suggestion, don't ask a question of a vendor that you don't already know the answer to. You'll learn a lot more about PV that way and almost as important, how many vendors don't know as much as you will and usually B.S. the solar ignorant.

[Wannaretireearly]

As a suggestion, don't ask a question of a vendor that you don't already know the answer to. You'll learn a lot more about PV that way and almost as important, how many vendors don't know as much as you will and usually B.S. the solar ignorant.

Agree. Im trying to pick up as much info as I can!

[Wannaretireearly]

As a certified Tesla installer who has designed numerous Powerwall systems I would suggest that you request your installer use a Gateway 2. This Gateway has a 12 slot internal panelboard option that can hold 3 full size 2 pole breakers or 6 Eaton Quad breakers. It can be configured to be either a unbacked up heavy load panel or an essential load panel.

Andy

Thanks. Appreciate any pointers as it looks like I'll only get one chance to ask questions and influence the design/install.

What are your thoughts on going with a 4kw Tesla system (12 panels) with a powerwall, where other vendors are generally sizing me at 5.5kw and about 16 panels? The jump with Tesla from 4 to 8 kw seems huge/overkill. But I dunno...

[RichardCullip]

Thanks. Appreciate any pointers as it looks like I'll only get one chance to ask questions and influence the design/install.

What are your thoughts on going with a 4kw Tesla system (12 panels) with a powerwall, where other vendors are generally sizing me at 5.5kw and about 16 panels? The jump with Tesla from 4 to 8 kw seems huge/overkill. But I dunno...

It’s hard for us to help you with the decision btwn a 4kw and a 5.5kw system without knowing your total energy use. Any idea how much electricity ( in kWh not in $) you used in the last 12 months?

[scrambler]

There really are two issues here for which we have no info.
How big of a solar array is driven by a few key elements.
- What is the yearly kWh you want to cover
- What is the location orientation, pitch of the array, and is there no shade issue

How big of a battery you need driven by
- What is the max sustain load and max peak load of all the critical loads you want to power during an outage.

[Wannaretireearly]

Richard & Scrambler, thanks.

I figured out I used 7658 kwh last year.
My total electric bill was actually $2064 ($172 a month).
I dont have any shade issues. The front of the house faces east. Sorry, no idea on the pitch of the roof.

Appreciate your help!

[RichardCullip]

Richard & Scrambler, thanks.

I figured out I used 7658 kwh last year.
My total electric bill was actually $2064 ($172 a month).
I dont have any shade issues. The front of the house faces east. Sorry, no idea on the pitch of the roof.

Appreciate your help!

I'm not sure what your goal for solar is, but if you hope to cover 100% of your current electrical usage, you might be slightly under-sized. My 4kW system (12 335W panels oriented 191 degrees and tilted at 23 degrees) produced 7467kWh in the first 12 months. I have no shade issues and all panels face slightly west of south. This performance slightly exceeded both my expectations and the installer's more conservative estimate. You won't have any excess generation to cover future growth in electrical use (e.g. adding an EV)

The jump to the next size installation that Tesla offers might, as you say, be too big a jump. That's one of the disadvantages to Tesla - they offer set sizes with little to no room for customization to fit specific situations.

Good luck with your decision.

[J.P.M.]

Wanna:

A lot of the questions coming at you and the reasons why they are being asked be answered by a read of "Solar Power Your Home for Dummies". At least you'll be better able to understand what the questions are. It's a free PDF on line for a dated but still useful ed., or ~ $25 at bookstores/Amazon for a newer/revised ed.

Read it and after that get familiar w/ something called PVWatts and you'll probably have as much necessary knowledge as most solar peddlers.

Given that usage, which is actually pretty low compared to the U.S. average, depending on your location, if you a decent solar climate, a 4 STC kw system might well produce ~ 6,000 kWh/yr. of your usage. For a lot of reasons, that may (or may not) be the most cost effective size.

I've got a PV system. It's not cost effective, and probably never will be, but that's not why I have it. Given my usage and the way I designed it, I knew it would probably never break even. I didn't do it for cost effectiveness, but I'm different than most folks in that respect.

My annual usage is quite similar to yours and every situation is different, but even if I'd sized and designed my system for max. cost effectiveness (again, which I didn't do) with what would have been, at the time of startup, a priori knowledge of future actual usage and production, I'd still be about 6 years from a positive ROI.

Or, put another way, if instead of putting what would have been ~ $11,300 (after tax credit) into a 4.2 STC kW system in Oct., 2013, I'd have simply put the funds into an S & P 500 index fund, I'd now have ~ $25,700 worth of 500 index fund. If I'd have done that, my total electric bills (because I would have no PV) for the same period would have been pretty close to $11,950.

That's an oversimplification because it leaves other factors in a serious time value of money cost analysis such as lost investment income on the (assumed) reinvested bill savings, or the bills being paid w/after tax $$'s and tax consequences of the S & P returns either way, but most of those and other things are rolled into why I'd still be ~ 6 years or so from break even. Still, $25.7K - $11.3K is a fair chunk of change to make a mistake with. A good market and I might never break even. A poor(er) market and it may break even some day.

Solar peddlers will estimate low on annual system production for several reasons, some of which make a certain amount of sense, but mostly because doing so makes it easier for peddlers to B.S. solar ignorant customers into buying more than they need or is in their (the customer's) best interests. Oversize as you please, but if you do, I'd respectfully suggest at least know where oversizing begins and what it will cost in terms of economic penalty.

The Dummies book, and after that PVWatts will help eliminate or at least help reduce the consequences of what's currently your Achilles heel in solar energy knowledge and help you get a safer, better and more cost effective design as well as helping to spot peddler B.S.

What's your zip ?

[Ampster]

Thanks. Appreciate any pointers as it looks like I'll only get one chance to ask questions and influence the design/install.

What are your thoughts on going with a 4kw Tesla system (12 panels) with a powerwall, where other vendors are generally sizing me at 5.5kw and about 16 panels? The jump with Tesla from 4 to 8 kw seems huge/overkill. But I dunno...

To me the question is what is the total cost of a 5.5kW system from other vendors versus the total cost of of a 8kW system from Tesla. I admit I am in the minority in terms of seeing value in overpanelling a system. I agree with @RichardCullip that if you see some growth in your consumption with an EV it could be a good hedge.

[Wannaretireearly]

Wanna:

A lot of the questions coming at you and the reasons why they are being asked be answered by a read of "Solar Power Your Home for Dummies". At least you'll be better able to understand what the questions are. It's a free PDF on line for a dated but still useful ed., or ~ $25 at bookstores/Amazon for a newer/revised ed.

Read it and after that get familiar w/ something called PVWatts and you'll probably have as much necessary knowledge as most solar peddlers.

Given that usage, which is actually pretty low compared to the U.S. average, depending on your location, if you a decent solar climate, a 4 STC kw system might well produce ~ 6,000 kWh/yr. of your usage. For a lot of reasons, that may (or may not) be the most cost effective size.

I've got a PV system. It's not cost effective, and probably never will be, but that's not why I have it. Given my usage and the way I designed it, I knew it would probably never break even. I didn't do it for cost effectiveness, but I'm different than most folks in that respect.

My annual usage is quite similar to yours and every situation is different, but even if I'd sized and designed my system for max. cost effectiveness (again, which I didn't do) with what would have been, at the time of startup, a priori knowledge of future actual usage and production, I'd still be about 6 years from a positive ROI.

Or, put another way, if instead of putting what would have been ~ $11,300 (after tax credit) into a 4.2 STC kW system in Oct., 2013, I'd have simply put the funds into an S & P 500 index fund, I'd now have ~ $25,700 worth of 500 index fund. If I'd have done that, my total electric bills (because I would have no PV) for the same period would have been pretty close to $11,950.

That's an oversimplification because it leaves other factors in a serious time value of money cost analysis such as lost investment income on the (assumed) reinvested bill savings, or the bills being paid w/after tax $$'s and tax consequences of the S & P returns either way, but most of those and other things are rolled into why I'd still be ~ 6 years or so from break even. Still, $25.7K - $11.3K is a fair chunk of change to make a mistake with. A good market and I might never break even. A poor(er) market and it may break even some day.

Solar peddlers will estimate low on annual system production for several reasons, some of which make a certain amount of sense, but mostly because doing so makes it easier for peddlers to B.S. solar ignorant customers into buying more than they need or is in their (the customer's) best interests. Oversize as you please, but if you do, I'd respectfully suggest at least know where oversizing begins and what it will cost in terms of economic penalty.

The Dummies book, and after that PVWatts will help eliminate or at least help reduce the consequences of what's currently your Achilles heel in solar energy knowledge and help you get a safer, better and more cost effective design as well as helping to spot peddler B.S.

What's your zip ?

Thx!! My zip is 94536

[Wannaretireearly]

To me the question is what is the total cost of a 5.5kW system from other vendors versus the total cost of of a 8kW system from Tesla. I admit I am in the minority in terms of seeing value in overpanelling a system. I agree with @RichardCullip that if you see some growth in your consumption with an EV it could be a good hedge.

Hi - the quotes from 2 or 3 others are roughly $20k for LG panels for a 5.5kw system. 16 panels.
The powerwall prices have been roughly around 12 to 15k incl installation.

This is where Tesla directly seems cheaper. But I am worried about bait n switch. I haven't seen a contract yet.

I would love to see input from Tesla solar customers in the SF bay area. I'm in zip 94536

[Ampster]

Hi - the quotes from 2 or 3 others are roughly $20k for LG panels for a 5.5kw system. 16 panels.
The powerwall prices have been roughly around 12 to 15k incl installation.

This is where Tesla directly seems cheaper. But I am worried about bait n switch. I haven't seen a contract yet.

I would love to see input from Tesla solar customers in the SF bay area. I'm in zip 94536

The best place for that would be the teslamotorsclub.com forum. That site is independent from Tesla. There are honest opinions there and quite a lot of Bay Area contributors. Of course there are Fanboys as well but as to your last question I think you will get an honest answer based on facts.This is new pricing for Tesla. One recent situation reported there is that a customer put in a new solar ready 200 Amp panel and was told by Tesla as they were getting ready for the install that they had to replace the panel. Several people gave him some contacts to escalate to a higher supervisor but I haven't checked to see how it was resolved.
Good luck. You are asking the right questions. You can message me over there with the same handle.

[Wannaretireearly]

The best place for that would be the teslamotorsclub.com forum. That site is independent from Tesla. There are honest opinions there and quite a lot of Bay Area contributors. Of course there are Fanboys as well but as to your last question I think you will get an honest answer based on facts.This is new pricing for Tesla. One recent situation reported there is that a customer put in a new solar ready 200 Amp panel and was told by Tesla as they were getting ready for the install that they had to replace the panel. Several people gave him some contacts to escalate to a higher supervisor but I haven't checked to see how it was resolved.
Good luck. You are asking the right questions. You can message me over there with the same handle.

Excellent. Thanks Ampster!

[solar_future]

All Tesla solar panel systems now cost the same per-watt regardless of size of the system. The video says the cost is $2.01 a watt before incentives. https://www.youtube.com/watch?v=BNgLhShBA4g. So a 4 KW system now costs $8,200 vs $10,000 before. The 8 KW systems goes for $16400 vs $16000 before.

[SunEagle]

All Tesla solar panel systems now cost the same per-watt regardless of size of the system. The video says the cost is $2.01 a watt before incentives. https://www.youtube.com/watch?v=BNgLhShBA4g. So a 4 KW system now costs $8,200 vs $10,000 before. The 8 KW systems goes for $16400 vs $16000 before.

What it did not make clear to me was if these are the standard solar panels or the solar shingles. If it is the panels then it sounds like a great buy.