Difference between SunPower SPR-E20-327 and X20-327?

[J.P.M.]

My system is 12.5kw approx. 38 Sunpower x20-327's....As for tilt and azimuth...No idea...

I am not BS'ing you..My peak sunny day was 74KWH....in May...during the summer I was mid 60's consistently.

Look at this screen capture for April 2nd...It rained that day and the system made 19.319KWH...I was shocked.

[ATTACH=CONFIG]5008[/ATTACH]

TM

FWIW, I believe you. I'd only suggest keeping in mind that some cloudy days are "sunnier" than others. Actually, there is a lot more day/day variability than most folks realize on all days, but particularly cloudy/hazy days for a boatload of reasons. Depending on system orientation/time of year, etc, a system's output on a VERY cloudy day ( low "clearness index" ~ = .15-.20) may be no more than approx. 10% of that if the same day was clear and cloudless (high "clearness index" ~ = .70 -.73).

[russ]

Gotta give PVWatts some credit, if you compare those numbers to what's in the system monitor that was linked in post #22, it is almost dead on.

Which means the panels in question perform about the same as any other panel.

[sensij]

From PV Watts for your location - PV Watts calls for 1525 kWh in October -

If Sunpower does what you claim it would be in the company advertising and not just from a salesman's mouth.

Gotta give PVWatts some credit, if you compare those numbers to what's in the system monitor that was linked in post #22, it is almost dead on.

[russ]

From PV Watts for your location - PV Watts calls for 1525 kWh in October -

If Sunpower does what you claim it would be in the company advertising and not just from a salesman's mouth.

Requested Location	Ladera Ranch CA
Weather Data Source	(TMY2) LONG BEACH, CA 36 mi
Latitude	33.82° N
Longitude	118.15° W
DC System Size	12.5 kW
Module Type	Standard
Array Type	Fixed (open rack)
Array Tilt	20°
Array Azimuth	180°
System Losses	14%
Inverter Efficiency	96%
DC to AC Size Ratio	1.1
Average Cost of Electricity Purchased from Utility	0.16 $/kWh
Initial Cost	3.70 $/Wdc
Cost of Electricity Generated by System	0.19 $/kWh

3.91	1,196	196
4.61	1,276	209
5.34	1,623	265
6.31	1,837	300
6.49	1,937	317
6.56	1,899	310
7.09	2,073	339
6.99	2,030	332
6.09	1,728	283
5.10	1,525	249
4.29	1,262	206
3.78	1,147	188
5.55	19,533	$ 3,194

[sensij]

Running simulations in SAM could help put the difference in perspective. Here is an illustrative example, your actual numbers are sure to be different!

Let's say you've got 2 strings of 8 Sunpower X20-327-BLK panelsv(5.232 kW). Under some assumptions (including 0.25% degradation), year 1 generates 9200 kWh, year 25 generates 8664 kWh.

Now, keeping the assumptions the same, except degrade at 0.5% annually, and build the system with LG 275N1C-G3's.
Bumping each string up to 10 panels yields a 5.4 kW system. Year 1 generates 9800 kWh, Year 25 generates 8689 kWh.

Another alternative in between is to use strings of 9 LG 300NIC-G3's (also 5.4 kW). Year 1 generates 9702 kWh, Year 25 generates 8602 kWh.

I don't have pricing for these three hypothetical systems and cannot tell you which is the best value. However, if I was shopping and considering the Sunpower panels, I am sure I would want to get proposals for the non-sunpower configurations too.

Interestingly, SAM choked if I tried to put more than 8 Sunpower panels in a string on the SE6000 inverter. It said the voltage was too high (526.16 V with 9 panels, 584.62 V with 10 panels). This kind of jives with the data sheets, which lists the inverter at 500 V max, and the Sunpower's at 57.3 Vmp, and 67.6 Voc. Tracy's system has already survived the year, and at least one string is pretty much south facing... is there anyone with more experience than I have that would like to speculate why this works?

[bcroe]

What does that mean? run at 10%? 10% of rated power?

Meaning, a 250W panel may be putting out 25W for 10 hours under cloud cover. Bruce Roe

[granders51]

I have seen my panels run at 10% all day long with no clear sky. But they aren't Sunpower. Bruce Roe

What does that mean? run at 10%? 10% of rated power?

[bcroe]

What do I stand to gain?

I have seen completely cloudy/overcast days where my system makes 20KWH in a day and cover almost 100% of my usage....less efficient system's would not produce that. Take it for what it's worth.....

Let's do this....in 5 years....let's compare output #'s? Everyone's a rock star in year one...Let's see what your system in producing 5 years from now...Bet the Sunpower panels lose less. TM

I have seen my panels run at 10% all day long with no clear sky. But they aren't Sunpower. Bruce Roe

[Jskeyes2]

Pretty interesting. I am going to follow up see if others haven input.

[granders51]

Did you install the P400 or P300 optimizers? If P300, you might be clipped some times. You should ask your installer to enable your public site so you can share. Unfortunately your link is for your private site which I can't see. But in terms of production, your AC W/DC W is 1.07e6/327/38 = 86.1. Mine is 480e3/4800 = 100. It's only been 2 months, so I can't say in 5 yrs what's going to happen. But at least the initial benefit doesn't seem to be power efficiency, but rather area efficiency.

Here is the public link to my system monitoring.

http://bit.ly/1wiPqDC

[granders51]

Did you install the P400 or P300 optimizers? If P300, you might be clipped some times. You should ask your installer to enable your public site so you can share. Unfortunately your link is for your private site which I can't see. But in terms of production, your AC W/DC W is 1.07e6/327/38 = 86.1. Mine is 480e3/4800 = 100. It's only been 2 months, so I can't say in 5 yrs what's going to happen. But at least the initial benefit doesn't seem to be power efficiency, but rather area efficiency.

p400's I am told.

[granders51]

Did you install the P400 or P300 optimizers? If P300, you might be clipped some times. You should ask your installer to enable your public site so you can share. Unfortunately your link is for your private site which I can't see. But in terms of production, your AC W/DC W is 1.07e6/327/38 = 86.1. Mine is 480e3/4800 = 100. It's only been 2 months, so I can't say in 5 yrs what's going to happen. But at least the initial benefit doesn't seem to be power efficiency, but rather area efficiency.

OK...I will ask...I thought you could see mine...let me check.

[granders51]

production

Maybe the best thing to do is compare production on different days...

Cloudy, sunny etc....System size is irrelevant...If you make x% of power on e day and then less 27% the next on a cloudy day....and I make only less 15% then there is something to be said about the equipment, No?

[thejq]

Did you install the P400 or P300 optimizers? If P300, you might be clipped some times. You should ask your installer to enable your public site so you can share. Unfortunately your link is for your private site which I can't see. But in terms of production, your AC W/DC W is 1.07e6/327/38 = 86.1. Mine is 480e3/4800 = 100. It's only been 2 months, so I can't say in 5 yrs what's going to happen. But at least the initial benefit doesn't seem to be power efficiency, but rather area efficiency.

[J.P.M.]

One thing I would say that is often overlooked...My Sunpower panels turn on early and make more power, even on cloudy day's or even rainy days than I would ever expect.....From speaking to my rep he says the power I am seeing is power that would never be generated from other, less efficient systems.

You usually get what you pay for....and with Sunpower I feel that it was money well spent...and in the long haul it was the best money spent.

TM

Pay your money, take your choice. A lot of other opinion feels differently for what seem to be pretty sound reasons and experience that sounds a lot more substantial than salespersons hype.