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sleevemedia

Member
Jul 1, 2020
57
41
Orlando
it's the difference between these two panels. if the panels can be seen from the street, the truly black ones look a LOT better.

OK, but the panels on the right are not on offer from Tesla, so that's what threw me off. OP said the panels are black and a bit more decorative than Tesla, that's what made me comment about the blackness of the Q.Cells Tesla uses.
 

astrorob

stealth performance M3
Aug 27, 2014
484
116
oakland, ca
OK, but the panels on the right are not on offer from Tesla, so that's what threw me off. OP said the panels are black and a bit more decorative than Tesla, that's what made me comment about the blackness of the Q.Cells Tesla uses.

sure, but i thought there was talk of installing a sunpower PV system with powerwallls upthread. so those high output and black panels are the differentiator for sunpower over tesla.
 

bkp_duke

Well-Known Member
May 15, 2016
5,551
19,376
San Diego, CA
sure, but i thought there was talk of installing a sunpower PV system with powerwallls upthread. so those high output and black panels are the differentiator for sunpower over tesla.

Yeah, and the Sunpower are substantially more efficient as well, in addition to having a lower annual degradation rate.
 

astrorob

stealth performance M3
Aug 27, 2014
484
116
oakland, ca
Yeah, and the Sunpower are substantially more efficient as well, in addition to having a lower annual degradation rate.

true.i should calculate what mine is. it's a little difficult since i've only cleaned the panels once and also i have 5.4kwh of panels against a 5kw inverter so some of the degradation is probably hidden. i did a back of the envelope one day and i got about 5% cumulative over the 5yr since install.
 

sleevemedia

Member
Jul 1, 2020
57
41
Orlando
Yeah, and the Sunpower are substantially more efficient as well, in addition to having a lower annual degradation rate.

Share the math, please? All I've found so far is companies that sell SunPower and compare the SunPower 415 against the Hanwha 315. If SunPower installers need to go to those extremes to make their point, I'm not interested in their pitch.

I see a .25% degradation and an expected 92.7% performance at 25 years for SunPower. That's a good number for anyone who expects solar panels they buy in 2020 to still be on their roof in 2045, or 2040, or even 2030. Solar chemistry is not mature, and my ROI is 6.7 years. When I rip and replace the Hanwha panels in 2030~35, they will have lost 5-7.5%, aka, have 92.5 to 95% of their initial performance. Because my ROI is 6.7 years, I don't really need to think about the panels in their 16th-25th years because they will have been donated to charity by then.

Generally, in any technology that still has innovation velocity, the sweet spot is two to three tiers down from bleeding edge due to propensity to upgrade during the useful life of the product. This is the case with CPUs and video cards. A lot has happened to solar in the past 20 years, and now it's accessible to a scrub like me. But when I look out 10 years, I expect to be able to buy a replacement system with lower cost, more efficiency and less degradation with a short enough ROI that the decision is like buying 4 new tires.
 
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sleevemedia

Member
Jul 1, 2020
57
41
Orlando
sure, but i thought there was talk of installing a sunpower PV system with powerwallls upthread. so those high output and black panels are the differentiator for sunpower over tesla.

Still not following. Who uses the fugly ice cube tray panels? Sunpower? The panels Tesla sells are solid black.
 
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bkp_duke

Well-Known Member
May 15, 2016
5,551
19,376
San Diego, CA
Share the math, please? All I've found so far is companies that sell SunPower and compare the SunPower 415 against the Hanwha 315. If SunPower installers need to go to those extremes to make their point, I'm not interested in their pitch.

I see a .25% degradation and an expected 92.7% performance at 25 years for SunPower. That's a good number for anyone who expects solar panels they buy in 2020 to still be on their roof in 2045, or 2040, or even 2030. Solar chemistry is not mature, and my ROI is 6.7 years. When I rip and replace the Hanwha panels in 2030~35, they will have lost 5-7.5%, aka, have 92.5 to 95% of their initial performance. Because my ROI is 6.7 years, I don't really need to think about the panels in their 16th-25th years because they will have been donated to charity by then.

Generally, in any technology that still has innovation velocity, the sweet spot is two to three tiers down from bleeding edge due to propensity to upgrade during the useful life of the product. This is the case with CPUs and video cards. A lot has happened to solar in the past 20 years, and now it's accessible to a scrub like me. But when I look out 10 years, I expect to be able to buy a replacement system with lower cost, more efficiency and less degradation with a short enough ROI that the decision is like buying 4 new tires.

I don't have to share the math, you did it right there. 0.25% degradation vs. the 1% or higher.

Plus, the rate of solar innovation is FAR LOWER than that in the integrated circuit filed ( i.e. CPUs and video cards). Simply put, you picked a bad analogy.

You are seriously going to rip panels off your roof in 15 years or less? Historically, if you look at how panel efficiency improves, it is on the average of 1-2% every 5 years for the high end panels, and over the past 10 years we have seen things plateau (i.e. the X21 panels on my roof are only superseded by the X22 panels, and both of those have been out 5-10 years, in fact SunPower's latest panel is no more efficient than the X series, it is just a bigger footprint to get to a higher panel wattage).

My panels need to last till I replace the roof in 25-30 years, even though with SoCal power rates the ROI on them is 5 years, then I will hope there is a nice integrated product like Tesla's solar roof (but at a better price point and with higher efficiency).

I seriously question anyone that is going to rip panels off their roof in under 10 years. I doubt that there will be a significantly better product available at that time, unless you compare apples to oranges and make the move to solar roof for aesthetics.
 
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astrorob

stealth performance M3
Aug 27, 2014
484
116
oakland, ca
Still not following. Who uses the fugly ice cube tray panels? Sunpower? The panels Tesla sells are solid black.

i didn't know that - have never seen a tesla installation. thought that upthread someone had put forth sunpower as an alternative because they couldn't get black panels from tesla.
 
So here is where Tesla is frustrating. They sent me an unsolicited redesign because the history on the house is less than one year and they are saying the load calculator is only coming up with 9100kWh / year in use. I can understand that based on the history but the house I'm in is new and we knocked down the house that was on the lot thus I thought the load calculator would help me out.

Here's what I entered into the load calculator and I may be missing some things
2 electric cars (I haven't been home charging them because 1 I got a week ago and they other and charging at 12 amps sucks. I've since installed a wall charger and I am very happy). I'll drive the S ~11,000/yr and the Y about half that.
3340 sq/ft home that is 5 beds 5.5 bathrooms a total of 16 finished, lighted, heated, a/c rooms (including bathrooms)
2 3.15 ton a/c units
12 wash loads per week
swimming pool gas heated but the filter uses plenty of electricity.
2 refrigerators
dishwasher
one electric oven
coffee maker, toaster oven, electric fryer, microwave
3 computers
6 TV's > 27"
high voltage landscape lighting
without running my pool (just finished or charging my cars) my bill was over 1200 kWh in June.

So I call Tesla and they say well you should be fine because the load calculator says so. Two other independent installers told me it would more like 17,000 kWh to support my annual consumption. I don't see the point in investing 43,500 bucks to support 50% of my energy use. This really sucks. I'm guessing one of the independent contractors may fight harder with the utility. I'm getting backed into going with another party purely over Tesla not wanting to review the load calculator and tell the utility that the history is meaningless.

edit: checked my meter. My June bill was marked est that my meter should say 12257 on July 1st. I don’t think that’s going to end up being true because today 7-23 14834 which is 2577 kWh so far in July. Could be I’ve starting charging two cars here but that would also make a 340 dollar bill.
 
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Southpasfan

Member
Jun 2, 2019
464
606
Pasadena
It does suck. I don't know that I would assume an independent installer would fight harder. The size of the system is something that the homeowner has to approve, whether its Tesla or someone else. I would bet that its the same fight either way. But it is your fight. You are fighting to spend more money. However, in my experience with contractors their incentive is to do the least amount of work possible to leave the client happy. Not a second more. Not saying a well done job is not the result, I'm just saying that this issue boils down to time spent arguing with a utility.

I anticipate a similar situation as we just moved and, due to two EV's probably anticipate more use than the historic use of the people who just sold us the house.

We will see. Let me put it another way, Telsa on my facts are $20k less. That's hundreds of hours of my time. Hundreds. Not a couple.
 
It does suck. I don't know that I would assume an independent installer would fight harder. The size of the system is something that the homeowner has to approve, whether its Tesla or someone else. I would bet that its the same fight either way. But it is your fight.

I anticipate a similar situation as we just moved and, due to two EV's probably anticipate more use than the historic use of the people who just sold us the house.

We will see. Let me put it another way, Telsa on my facts are $20k less. That's hundreds of hours of my time. Hundreds. Not a couple.
I don’t mind calling but they said they won’t reconsider it. Thus I’m either SOL or go elsewhere. I have a quote from a SunPower dealer that’s only about 7k more after taxes. That’s comparing to the larger system I did with Tesla. I’m also confused based on what I told them how they came up with that load calculation.
 

Southpasfan

Member
Jun 2, 2019
464
606
Pasadena
I am a bit unclear about who they is - who "won't reconsider it?" If its the utility, I'd ask who to talk to myself and throw some time at it. I can't believe that Tesla won't reconsider it.

I don't even know you, but you may be your own best advocate here. Far better than any installer employee. From Tesla or anyone else.
 

MP3Mike

Well-Known Member
Feb 1, 2016
16,422
38,289
Oregon
I know that @MorrisonHiker was limited, by the utility, in the size that they could installed based on historical usage, even accounting for new EVs in the household, and that after a year of additional usage data they were able to show that they used more and got the utility to approve installing additional capacity.

I think more people will run into this as the COVID/WFH situation has people driving/charging less which will reduce the usage and limit the size of the system that the utility will approve. (Even if things change and they start driving more, it will take a year to get the usage back.)
 
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I am a bit unclear about who they is - who "won't reconsider it?" If its the utility, I'd ask who to talk to myself and throw some time at it. I can't believe that Tesla won't reconsider it.

I don't even know you, but you may be your own best advocate here. Far better than any installer employee. From Tesla or anyone else.
Tesla doesn't want to redo the load calculations and resubmit them. Their rep told me it is what it is and asked me to e-sign the revisions. I can't see spending that for half my energy production because adding later will be more expensive than doing it up front. There has to be an error in what they collected during the phone discussion. Given what I've written how could that be an average 800 kWh / month? Moreover I am seeing an average usage of 1451.5 kWh. I'd hate to have to wait till next year to do this because the tax credit is being reduced. Two other installers calculated the loads used at 17.5 kWh which is inline with the actual data I am seeing on my meter.
 
I know that @MorrisonHiker was limited, by the utility, in the size that they could installed based on historical usage, even accounting for new EVs in the household, and that after a year of additional usage data they were able to show that they used more and got the utility to approve installing additional capacity.

I think more people will run into this as the COVID/WFH situation has people driving/charging less which will reduce the usage and limit the size of the system that the utility will approve. (Even if things change and they start driving more, it will take a year to get the usage back.)
Here's the issue. The house that had my current address I knocked down almost two years ago. We didn't have electricity in here until last ~May 2019 and the usage wasn't very much. The house was finished in November 2019 but I didn't spend anytime (3 visits total none overnight) until April 6th 2020. So yeah the heat ran and I turned on and off some lighting and the alarm but no occupancy. This was all explained. In fact to support it my C/O wasn't even granted until March 2, 2020.

April, May, June and July (MTD) averages 1451 kWh. the only month under 1000 kWh is April and it was 980 kWh for the limited days I was here.

Thus, we went through load calculations and I can't believe they could only just 800 kWh / month given what I've outlined. It's just not worth doing given what what they are offering me with no opportunity to review the load calculations over again. I'm guessing a small installer would put more effort into this, thus costing me more, but in the end getting me what I want.
 

Southpasfan

Member
Jun 2, 2019
464
606
Pasadena
Well, its either the old "ask to speak to a supervisor" move or go with another installer. It seems strange to me, that someone at Tesla would balk at redoing load calculations. Read through a bunch of these threads and some people have like ten revisions of the entire plan - from the number of panels to the structure of the wiring to the number of powerwalls etc. etc.

This is, in a way, "customer service" but the question is this. Say you go with another installer, who submits the plan you want and gets it approved. Well hold on a second, again, the problem is the magnitude of savings. If another installer can get it approved? Why? They're not bribing someone.

It doesn't matter if its an hour of time arguing with Tesla or an hour of time arguing with the utility. Its still only an hour. I'd be worried (convinced, actually) that I spent an extra ten grand when all I had to do was talk to someone else at Tesla.
 

bkp_duke

Well-Known Member
May 15, 2016
5,551
19,376
San Diego, CA
With Tesla definitely ask to speak to a supervisor.

I had a 4th Powerwall installed, which was a referral award that comes with $1000 in "installation credit". The agent was INSISTING that the install labor of $2500 minus the $1000 credit would leave me with $1500 to pay out of pocket.

Once I escalated the issue, and showed them that 1) we had pre-wired for a 4th powerwall, so this would be an easy installation, and 2) that they are not providing the gateway which they would normally do with a referral, the supervisor agreed that all installation costs should be covered out of the $1000 credit.

It does pay to be the squeaky wheel with Tesla Energy.
 
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MP3Mike

Well-Known Member
Feb 1, 2016
16,422
38,289
Oregon
I can't see spending that for half my energy production because adding later will be more expensive than doing it up front.

Is it really? (Barring the tax credit that goes down next year.) Tesla charges per watt and there isn't any bulk/size discount that I am aware of. So putting 50% now and 50% later would likely either cost the same of less. (Since solar prices seem to go down over time.)
 

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