Need advice on older Sunpower panels - Under $3.30/watt

[pizzam]

Hi everyone, new to the forum. I've just started getting quotes for a solar panel system. And some searches led me to this forum. I have a couple questions and was looking for opinions on this system. I'm in NH if that helps.

So right now it seems like one of the better quotes I've gotten is for either a 18 or 20 panel system using Sunpower's E19-320 watt panels. The local installer said there is a great deal on these panels right now. They are offering them even cheaper than Solarworld 285 panels. So I've gotten 2 quotes for the Sunpower system, 18 panels for $19,000 or 20 panels for $20,900. Both are pre-credits/rebates. They also come with Sunpower microinverters.

The 18 panels is based on my current annual usage of 6,500 kwh. The 20 panels is maxing out the space on my roof.

My first question is that it looks like Sunpower E19-320 panels are older. Any issues/comments going with these older panels? They seem to be better than what I have been offered so far (Solarworld 285 and Suniva 285).

Second question. Am I crazy for thinking I need 20 panels? I have an infant now and I'm sure as the family grows we will use more electricity. Also, the tax credit will go away soon I figured it might be worth taking advantage of. And I don't know if it's an issue to expand in the future with mixing different panels, etc. Also with the price of the current panels. It just seems like a good deal for a Sunpower system. After all credits it is an additional $1,300.

Thanks.

[J.P.M.]

Something doesn't sound right. For starters make sure all those prices are before tax credit, not after. Sunpower stuff is usually about $4.25 or more per Watt, pre tax credit. E320's are older, but that shouldn't have a large bearing on efficiency or quality, provided they're not sloppy seconds or used. For that price, if regular stock, they should have been gone long ago or never hit the market as insiders would know about them and snap them up.

If in the U.S, what's your zip ? That's a pretty big system for 6,500 kWh/yr. load for most of the U.S. Gross oversizing is a waste of money and materials. Run PVWatts for your location and keep in mind that conservation is always more cost effective than PV solar.

Download and read " Solar Power Your Home for Dummies." Get educated before you go further and don't rush things.

[brewbeer]

6,500 kWh/yr is about 18 kWh per day, which is close to what I use on average. A 6.4 kW system doesn't seem to be too large if you have shading issues. As your family grows, so will your power consumption. How long do you think you will be staying in the home? If you plan on moving in the near to medium term, think carefully about the solar system as it may not give you a net positive return on your money before you move.

[pizzam]

Something doesn't sound right. For starters make sure all those prices are before tax credit, not after. Sunpower stuff is usually about $4.25 or more per Watt, pre tax credit. E320's are older, but that shouldn't have a large bearing on efficiency or quality, provided they're not sloppy seconds or used. For that price, if regular stock, they should have been gone long ago or never hit the market as insiders would know about them and snap them up.

If in the U.S, what's your zip ? That's a pretty big system for 6,500 kWh/yr. load for most of the U.S. Gross oversizing is a waste of money and materials. Run PVWatts for your location and keep in mind that conservation is always more cost effective than PV solar.

Download and read " Solar Power Your Home for Dummies." Get educated before you go further and don't rush things.

Yes, that price is pre-credits. I emailed the installer to confirm that they are new panels. But if it true, it's like getting Sunpower for non-Sunpower pricing. When you say it's a big system, are you referring to the 18 panels or 20 panels?

And I plan on staying in this house for another 10 years if not longer.

[J.P.M.]

When you say it's a big system, are you referring to the 18 panels or 20 panels?

No. I'm referring to the idea that the system you are contemplating may be, depending on your location, oversized. For example, a 5,760Watt system in my area, with reasonable orientation and not much shading, will produce something like 9,500 to maybe 10,000 kWh/yr. If you were my neighbor, you'd be leaving money on the table by oversizing the system by 50 % or so. If in Seattle, for example, the same system, orientation and shading will produce about, 6,500 - 7,000 kWh/yr.

That's why I asked what your zip is. Also, given the tone of your questions, why I suggested the book. Download it for free and spend a couple hrs. reading, particularly the part about conservation. Then get more quotes and think long term quality in a vendor, not low initial buck.

It may be that the S.P. 320's are a legit deal, but if something seems too good to be true, it usually is too good (to be true). Caveat Emptor.

The Wattage of each panel and their number is less important than total wattage. A loose analogy: You want to buy about 5,760 lbm. of rocks for ballast and you pay for them by the lbm. Do you care if each rock weighs 285 or 320 lbm ?

[pizzam]

I am in NH. 03060. I did check out PVwatts per your recommendation. I wasn't sure what some of the inputs were so I left most of them as is and it calculated 7,500 kWh/yr. I would guess my location is very similar to Seattle.

So, this deal seems legit. I was also skeptical which is why I posted here. The vendor is also one of the larger installers here. They provided me with three pages of references. And on solarreviews.com they had the most reviews. And they seem to have been around the longest. I did get 3 other quotes besides this one.

I also did download the book and will be reading it tonight. Thanks for your input, advice and direction.

[J.P.M.]

I am in NH. 03060. I did check out PVwatts per your recommendation. I wasn't sure what some of the inputs were so I left most of them as is and it calculated 7,500 kWh/yr. I would guess my location is very similar to Seattle.

So, this deal seems legit. I was also skeptical which is why I posted here. The vendor is also one of the larger installers here. They provided me with three pages of references. And on solarreviews.com they had the most reviews. And they seem to have been around the longest. I did get 3 other quotes besides this one.

I also did download the book and will be reading it tonight. Thanks for your input, advice and direction.

For my part, you're welcome. Read the PVWatts help/info screens for better understanding of what it can and cannot do. Question everything everyone says, including and maybe particularly me. You're about to spend $20 K. Get informed. Again, Caveat Emptor.

Good luck.