Over Sizing Panels to Inverter?

[Murby]

Did you oversize your panels to your inverter? Seems that they are recommending up to 125% more panel capacity than inverter capacity... So now I'm thinking of putting in 6000 watts of panels on a 5000 watt inverter.
Any of you do this? How is it working out?

One other question, assuming the cost per watt remained the same, would you rather use higher power panels and fewer of them, or lower power panels but more of them?

Seems to me that the higher power panels might be newer technology? Maybe more reliable? But lower power panels would provide more redundancy...

[ButchDeal]

Did you oversize your panels to your inverter? Seems that they are recommending up to 125% more panel capacity than inverter capacity... So now I'm thinking of putting in 6000 watts of panels on a 5000 watt inverter.
Any of you do this? How is it working out?

Array being larger than inverters is the standard. How much depends on the situation though.

One other question, assuming the cost per watt remained the same, would you rather use higher power panels and fewer of them, or lower power panels but more of them?

BAD assumption. The price will NOT be the same for higher efficiency modules. (you stated higher power there are two ways to get higher power, higher efficiency and larger modules i.e. 72 cell vs 60 cell).

Seems to me that the higher power panels might be newer technology? Maybe more reliable? But lower power panels would provide more redundancy...

They are the same technology.
Reliability , they pretty much all come with 25 year warranty on production.

[Wy_White_Wolf]

....One other question, assuming the cost per watt remained the same, would you rather use higher power panels and fewer of them, or lower power panels but more of them?...

If cost per watt is than same then I would look at which one fits best in the string voltage needed by the inverter.

WWW

[Murby]

If cost per watt is than same then I would look at which one fits best in the string voltage needed by the inverter.

WWW

I don't understand that statement. The SMA inverter wants a minimum of 150 volts to a max of 600.. Since all the panels from the various brands seem to all produce between 30 and 40 volts each, I don't understand what you mean by matching string voltage to the inverter.. Would I be wrong to say that my inverter would be perfectly happy with anything between 300 and 500 volts?

[ButchDeal]

I don't understand that statement. The SMA inverter wants a minimum of 150 volts to a max of 600.. Since all the panels from the various brands seem to all produce between 30 and 40 volts each, I don't understand what you mean by matching string voltage to the inverter.. Would I be wrong to say that my inverter would be perfectly happy with anything between 300 and 500 volts?

The voltage and power production vary with temperature and wind (cooling ) as well as light angle (time of day, pitch, azimuth). So you need to insure that the voltage of the strings are sufficient for the expected weather conditions and array layout. Further most string inverters have a better efficiency at particular voltages, and many have multiple MPPT inputs, so the strings can be divided up (or not) among the inputs as needed.

Now on the original question about the module efficiency (power) different types of modules have different temperature curves as well as other aspects such as some are better at converting diffuse light to energy than others. If say you lived in a place with a lot of diffuse light (Washington state maybe) then you would want to use the modules that are better with diffuse. If you live in a place with very hot temperatures you might want to use modules with better power at high temperatures.

Of course there are many other things that homeowners like:
Black on Black modules (more expensive, a bit less efficient, worse high temp handling)
Made in US (more expensive)
Black frame (slightly more costly)
etc etc.

[Murby]

The voltage and power production vary with temperature and wind (cooling ) as well as light angle (time of day, pitch, azimuth). So you need to insure that the voltage of the strings are sufficient for the expected weather conditions and array layout. Further most string inverters have a better efficiency at particular voltages, and many have multiple MPPT inputs, so the strings can be divided up (or not) among the inputs as needed.

Now on the original question about the module efficiency (power) different types of modules have different temperature curves as well as other aspects such as some are better at converting diffuse light to energy than others. If say you lived in a place with a lot of diffuse light (Washington state maybe) then you would want to use the modules that are better with diffuse. If you live in a place with very hot temperatures you might want to use modules with better power at high temperatures.

Of course there are many other things that homeowners like:
Black on Black modules (more expensive, a bit less efficient, worse high temp handling)
Made in US (more expensive)
Black frame (slightly more costly)
etc etc.

Thank you very much! Now I have to digest this for a while and see how it works into my current plan.

[Spektre]

Higher power panels would use less roof space and require less racking and installation time, assuming you can fit them on your roof.

If anything, I've noticed lower cost/watt on the higher output (and 72-cell) panels, so why not go with them?

[Mike90250]

The SMA inverter wants a minimum of 150 volts to a max of 600.

That's just to operate, often the MPPT tracking is a smaller window, say 250 - 420V or something, that's what my XW-GT had.

[ButchDeal]

If anything, I've noticed lower cost/watt on the higher output (and 72-cell) panels, so why not go with them?

at wholesale 72 cell and 60 cell are almost identical cost ($/watt) with 72cell being just a bit more. They are difficult to handle though and do not come in Black on black, as well as few of them have black frames.
There would generally be a little less racking for 72 cell installations and everything else is almost the same. So it just isn't worth the added labor costs and often difficulty fitting the larger modules.

within the 60 cell modules we price shop for ones that we can get good deals on for a reasonable period of time (at least 3 months) and try to have all the bases covered (low cost, Black on Black, mono, US, high performance, HIT).

[jflorey2]

Did you oversize your panels to your inverter? Seems that they are recommending up to 125% more panel capacity than inverter capacity... So now I'm thinking of putting in 6000 watts of panels on a 5000 watt inverter. Any of you do this? How is it working out?.

I currently have 9680 watts of panels on 8700 watts of inverter. (111%) Haven't come close to maxing the system out.

[Murby]

at wholesale 72 cell and 60 cell are almost identical cost ($/watt) with 72cell being just a bit more. They are difficult to handle though and do not come in Black on black, as well as few of them have black frames.
There would generally be a little less racking for 72 cell installations and everything else is almost the same. So it just isn't worth the added labor costs and often difficulty fitting the larger modules.

within the 60 cell modules we price shop for ones that we can get good deals on for a reasonable period of time (at least 3 months) and try to have all the bases covered (low cost, Black on Black, mono, US, high performance, HIT).

Why does everyone like black on black? Black heats up faster and heat is an issue for solar panels. Also, what does HIT stand for?

[solar pete]

Many customers like the look of the black on black panels because it looks cooler (to them anyway)

[ButchDeal]

Why does everyone like black on black? Black heats up faster and heat is an issue for solar panels. Also, what does HIT stand for?

Heterojunction with Intrinsic Thin layer

[J.P.M.]

Many customers like the look of the black on black panels because it looks cooler (to them anyway)

efficiency is only a secondary issue for some with aesthetics trumping cost effectiveness. Pay your money, take your choice.

[dex]

People like BOB for the looks and HOA's will only allow BOB around here.

I have 72 cell all black panels. Guess it's a unicorn!