Solar system in Las Vegas

[lanb]

Looking to go solar for a 11500 kWh/year capacity system.

Here are the initial quotes I have gotten

6.72 DC kW with 21 Solarworld 320 panels with Solaredge inverter producing 11503 kWh/year - $21,821 ($3.24/kWh)
Warranty is 10/10

5.886 DC kW with 18 SunPower 327 panels with SMA inverter producing 11118 kWh/year - $25,528 ($4.33/kWh)
Warranty is 25/25

Now the questions -

1) Does that look like fair pricing ?
2) The installer mentioned that Solarworld 320's are way back ordered and wants to substitute with 280's (more panels).
He said that 280's are built with better cells. True or False ?
3) I have been reading about the risk of solarworld proprietary optimizers and what happens if they go out of business.
Is it possible to install solarworld panels without optimizers and just a string inverter ?

Thanks for all the helpful info here !

[lanb]

Bump

Bumping up the post for answers

[sensij]

Looking to go solar for a 11500 kWh/year capacity system.

Here are the initial quotes I have gotten

6.72 DC kW with 21 Solarworld 320 panels with Solaredge inverter producing 11503 kWh/year - $21,821 ($3.24/kWh)
Warranty is 10/10

5.886 DC kW with 18 SunPower 327 panels with SMA inverter producing 11118 kWh/year - $25,528 ($4.33/kWh)
Warranty is 25/25

Now the questions -

1) Does that look like fair pricing ?

Hard to say without more details, but for a straightforward install, yes, that looks like competitive pricing. The discrepancy between kWh estimates is worth understanding better. Two arrays with similar kW ratings will have similar kWh output. Either Sunpower is overestimating or the Solarworld installer is underestimating. Spend some time with PVWatts and see if you can come up with your own estimate. Try dropping the loss factor from the default 14% to 10%, or perhaps less.

2) The installer mentioned that Solarworld 320's are way back ordered and wants to substitute with 280's (more panels).
He said that 280's are built with better cells. True or False ?

Well, the SW320's are 72 cell panels, so if you scale that to 60 cells, it is something like a 265 W panel. The 280's are 60 cell panels, so in that respect, they should have higher cell efficiency (meets the definition of "better"?). I don't really see anything wrong with subbing the 280's, if the roof layout works for either 72 cell or 60 cell panels.

3) I have been reading about the risk of solarworld proprietary optimizers and what happens if they go out of business.
Is it possible to install solarworld panels without optimizers and just a string inverter ?

Yes, Solarworld panels can be installed with a string inverter.

[lanb]

Thanks for the info sensij.

I will play around with pvWatts to get the kWh estimate.

BTW, both quotes are from the same installer/company.

[lanb]

Manufacturing post count 8

[lanb]

Manufacturing post count 9

[lanb]

Manufacturing post count 10 !

Hurray !!

[inetdog]

Manufacturing post count 10 !

Hurray !!

Congratulations lanb, although some Moderators might take exception to your method of running up the count and delete some of the duplicates, putting you back below 10.

[lanb]

Thanks for the upvote and not deleting my posts

I was on the fence about this but then had to send a PM and was just 3 posts short !

[lanb]

BTW, I ran pvwatts and a 6 to 6.5 kwh system is what is required for my usage.

On another note, some of the companies in Las Vegas are promoting sunpower panels claiming that
the surface metal on the other panels are bad for the LV heat due to constant expansion and contraction.

Any truth to that, which warrants the higher premium for SP ?

Solarix - Can you check your PM please ?

[paul65k]

BTW, I ran pvwatts and a 6 to 6.5 kwh system is what is required for my usage.

On another note, some of the companies in Las Vegas are promoting sunpower panels claiming that
the surface metal on the other panels are bad for the LV heat due to constant expansion and contraction.

Any truth to that, which warrants the higher premium for SP ?

Solarix - Can you check your PM please ?

I've said this before and I'll say it again;

As long as you are using quality products and have a quality system installed there is no need to pay a premium for supposedly "Highest" quality panels for the following reasons:

• Your utility will make no differentiation in the amount of credit you receive for power produced coming from a premium panel
• When/if you go to sell your home no one will pay you more for your "Highest" quality panels, the value will be strictly associated with your recent/past experience of what your bills look like at that point in time.
• Warranties are only as good as the company and industry as a whole do in general and NO ONE can say for sure what any of the current companies will look like once the government subsidies get realistic from a purely business perspective........I personally like companies that do more than just Solar (LG comes to mind) but who really knows......companies that were once dominant in the field and part of much larger companies (Sharp as an example) are now out of the residential solar business so who really knows for sure.

I for one think the best advice is to find an installer that has the best track record...........not to be confused with having the best salespeople. Talk to at least 5 of their installed customers who have at least 2 year old installations and see what they have to say about the claims made by the salespeople.........solarreviews.com is a good place to start and 1:1 contact with previous clients is even better

[lanb]

Inverter question

After deciding to move away from the optimizer/micro inverters , I got another quote for solarworld panels with string SMA inverter.

Here are the specs :

22 280W SolarWorld panels connected to an SMA SB7000US-12 inverter for 6.2kW DC system producing 10,800 kwH/year

Now , after reading the posts here, I am thinking that using a SMA SB7000TL-US-22 would be better than
the SB7000US-12 because 14 of the panels will be on the south and 8 on the west (2 strings of 11 panels).

The designer/installer says that "the string sizing is not as versatile and doesn't work as well for the
TL series as it does for the US-12" and the US-12 will accept multiple strings and will work fine for this setup.

I also came across this - sunny-design-polystring-configuration/.

Here is the compare of the various SB7000 - SB 7000 compare

Am I overthinking the dual MPPT advantage ? Is a SMA SB7000US-12 good enough for my situation ?

Comments ?

[inetdog]

The one thing that I have to contribute to the process is that you should not, unless using micros or optimizers, put panels with different facing directions in one string.
You will have to have unmatched string sizes and the inverter must accept that imbalance between the inputs.
In addition, of course, the two strings will not be at max production at the same time, so you may be able to run with a smaller inverter than the straight sum of panel wattages would suggest.

[lanb]

Yeah I was wondering about that too - putting two strings of 11 each unless there is some max wattage reason.

Like you said, I would think the west (8) would all be one string and the south (14) would be on another string.

One question - what is the max number of 280W panels that the SB7000 can support on one string ?

[gogreenmakegreen]

Own your system for free Its true and real

Looking to go solar for a 11500 kWh/year capacity system.

Here are the initial quotes I have gotten

6.72 DC kW with 21 Solarworld 320 panels with Solaredge inverter producing 11503 kWh/year - $21,821 ($3.24/kWh)
Warranty is 10/10

5.886 DC kW with 18 SunPower 327 panels with SMA inverter producing 11118 kWh/year - $25,528 ($4.33/kWh)
Warranty is 25/25

6

Now the questions -

1) Does that look like fair pricing ?
2) The installer mentioned that Solarworld 320's are way back ordered and wants to substitute with 280's (more panels).
He said that 280's are built with better cells. True or False ?
3) I have been reading about the risk of solarworld proprietary optimizers and what happens if they go out of business.
Is it possible to install solarworld panels without optimizers and just a string inverter ?

Thanks for all the helpful info here !

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