Help with an undersized inverter used in my system!

[PseudoCode]

Greetings!
I

[russ]

Comments are in bold in the text - if anyone has a beef with a company it is best to not mention dealer/installer names as this fellow correctly did.

Russ

[QUOTE=PseudoCode;45225]Greetings!

On these sunny days we miss out on a good 5 hours of additional production wasted due to the undersized inverter. If you graph our power production it

[Wy_White_Wolf]

Was this a purchase or a lease?

[Naptown]

Perhaps a call to MDVSEIA and registering a complaint with them, Montgomery County department of consumer affairs and the Better Business bureau. A call to the contractor alerting them to these wouldn't hurt. Maybe get their attention.

http://www.mdv-seia.org/index.html this is SEIA's website
They have no email contact info on the site that I could see.

[Naptown]

Comments are in bold in the text - if anyone has a beef with a company it is best to not mention dealer/installer names as this fellow correctly did.

Russ

You're ruining all my fun

[PseudoCode]

Was this a purchase or a lease?

bought it.

[Ian S]

Besides taking them to court, does anybody have any suggestions/thoughts as to how I can get them to provide us with the correct inverter? This is a 9 month old system! One final thing, the company charged us by panel watt as a package deal (we had no say in the inverter size) so we are being taking advantage of with the inverter bottleneck by never actualizing all of our potential panel power.

It sure seems the company screwed up and should make it right. If they don't, I'm not sure it makes financial sense to take them to court. Complain to BBB and see how that goes. If it still doesn't work then give poor ratings on sites like yelp. Even if you can't get satisfaction, others will get forewarned of poor customer service.

Hey, maybe Naptown would give you a deal on trading the inverter in for the right size one.

[Naptown]

OK all joking and kidding aside.
After further thought on this
Here is the reality of the situation.
We are just past the time of year that the sun is directly perpendicular to your panels. this is the time of year when you have two things going for you.
1- the sun is in its position most perpendicular to your roof meaning that the angle of incidence is very low and will produce the most power.
2- The cool weather is keeping the cells cooler thus they are producing more power.

Once the sun gets higher in the sky and the temperature rises to the typical 85-90 degrees your panels will not be putting out nearly as much power as they have been. Add the higher humidity levels during the summer and further losses in peak power. We have also had a large number of cool very low humidity days this spring.

So now that we are headed for lower peak power till fall (which is generally not as good as spring as it is warmer.) you will probably not see this happen much any more this summer.
How many days did the inverter clip to max power.

I would imagine that overall the contractor and manufacturer are not too far off in their estimation of 1% loss.

[Ian S]

Naptown's probably right. Still, it's seems a stupid corner to cut - difference in price of the inverters is only a couple hundred $$. Makes you wonder what other corners they cut or mistakes they made.

[PseudoCode]

OK all joking and kidding aside.
After further thought on this
Here is the reality of the situation.
We are just past the time of year that the sun is directly perpendicular to your panels. this is the time of year when you have two things going for you.
1- the sun is in its position most perpendicular to your roof meaning that the angle of incidence is very low and will produce the most power.
2- The cool weather is keeping the cells cooler thus they are producing more power.

Once the sun gets higher in the sky and the temperature rises to the typical 85-90 degrees your panels will not be putting out nearly as much power as they have been. Add the higher humidity levels during the summer and further losses in peak power. We have also had a large number of cool very low humidity days this spring.

So now that we are headed for lower peak power till fall (which is generally not as good as spring as it is warmer.) you will probably not see this happen much any more this summer.
How many days did the inverter clip to max power.

I would imagine that overall the contractor and manufacturer are not too far off in their estimation of 1% loss.

To give you an idea of how much clipping occured by the inverter! For the past 297 days we had 117 days of clipping (i.e. days where the inverter maxed out in its DC to AC conversion @ 5,110w AC). That's 40%!

Thank you to everyone with their suggestions! Keep'em comming and for folks looking at a new system
please pay attention to the inverter dc/ac rates to make sure your getting what you pay for.

[PseudoCode]

Naptown's probably right. Still, it's seems a stupid corner to cut - difference in price of the inverters is only a couple hundred $$. Makes you wonder what other corners they cut or mistakes they made.

I agree with the cost cutting however our installer insists that Sunpower charges the same price for both the 5000m and 6000m inverter.

[Naptown]

To give you an idea of how much clipping occured by the inverter! For the past 297 days we had 117 days of clipping (i.e. days where the inverter maxed out in its DC to AC conversion @ 5,110w AC). That's 40%!

Thank you to everyone with their suggestions! Keep'em comming and for folks looking at a new system
please pay attention to the inverter dc/ac rates to make sure your getting what you pay for.

I would have expected maybe 10 -15 days not 117
It is worse than I thought.

[PseudoCode]

I would have expected maybe 10 -15 days not 117
It is worse than I thought.

That's the problem I'm having with the installation company & SunPower. They keep going back to the PV Watts estimate for my system (which results in much lower energy production values) and ignoring the actual system production values which I downloaded from the Sunpowermonitor.com site for my PV system. The actual production numbers clearly show the problem. I thought that I covered everything during our contract talks prior to the written agreement for our PV system. The cost of the system is based on DC panel watts which I am never going to realize due to the inadequate inverter they installed. Yes for a handful of months during the year the system does not clip/max out and I view the expected parabola curve and I realize that I will never attain over 6,000 w AC (assuming I have the correct inverter) from my 6.21w DC set of panels. But when you invest so much money into a system, I'm out there cleaning the panels of pollen and removing snow to ensure optimum operating its unforgiving for a company to short change on the inverter.

[Ian S]

To give you an idea of how much clipping occured by the inverter! For the past 297 days we had 117 days of clipping (i.e. days where the inverter maxed out in its DC to AC conversion @ 5,110w AC). That's 40%!

Thank you to everyone with their suggestions! Keep'em comming and for folks looking at a new system
please pay attention to the inverter dc/ac rates to make sure your getting what you pay for.

Just FYI: I saw the ASCI graph in my email notification but not here. Anyway, I use a great little screen capture freebie called Screenhunter that captures to jpg according to an area you can select with the mouse. I know the Sunpower software gives a nice bar graph and you could have attached a jpg of it quite easily. It looks like that particular day, it might have clipped 20-25% of your generated kWh.

[PseudoCode]

Just FYI: I saw the ASCI graph in my email notification but not here. Anyway, I use a great little screen capture freebie called Screenhunter that captures to jpg according to an area you can select with the mouse. I know the Sunpower software gives a nice bar graph and you could have attached a jpg of it quite easily. It looks like that particular day, it might have clipped 20-25% of your generated kWh.

Thank you for pointing out the image attachment feature. This is a day from March clearly showing the clipping at 5,110w AC generation for several hours. I highlighted the missing energy and will use basic calculus to determine the area under each curve in an attempt to identify/quantify the amount of power that was not realized.

SunPowerImage1.jpg