Confusion re module rating, microinverter rated output power, and PVWatts.

[ImInPhxAZ]

I'd ask for an updated quote with iq6. Remember the panel rating is peak output also. Perfect conditions, perfect angle. Pop one panel in pvwatts with the orientation you plan to see some real world and look at hour by hour. Chances are you won't miss much.

[inspron]

from a reputable local company.

I would question the assertion this installer as being reputable. How big is your system and what city are you in?

If you are very far north, it is possible that M215 could work since you are unlikely to achieve outputs in excess of 215W even in the summer with the 290W panels.

But if you are in the south, this pairing sounds like your installer trying to dump old inventory of microinverters now that IQ models are out.

[J.P.M.]

Thanks, I will have a look. Here is the Enphase video that recommends pairing the M250 with a 330W module: https://www.youtube.com/watch?v=Vx0dzxvfw4M. I don't know why the reputable company I have the quote from paired the M215 with a 290W module, but that is what they did.

Perhaps your opinion of their reputability is not warranted. Happens all the time.

[J.P.M.]

J.P.M., did a search for Solar Power Your Home for Dummies in a free format and it looks like all the links have been disabled! Just an FYI

OOPS ! You seem to be correct. Guess we'll need to spend 20 bucks for the 3d ed. The free ride is over.

Thank you for the correction and information.

Even at $20 or so, still a value.

J.P.M.

[ButchDeal]

Thanks, I will have a look. Here is the Enphase video that recommends pairing the M250 with a 330W module: https://www.youtube.com/watch?v=Vx0dzxvfw4M. I don't know why the reputable company I have the quote from paired the M215 with a 290W module, but that is what they did.

That is over 3 years old. It would be far better to par a 330w with the newer Q series or even better to go with solaredge.

[wexcellent]

J.P.M., did a search for Solar Power Your Home for Dummies in a free format and it looks like all the links have been disabled! Just an FYI

[wexcellent]

Thanks, I will have a look. Here is the Enphase video that recommends pairing the M250 with a 330W module: https://www.youtube.com/watch?v=Vx0dzxvfw4M. I don't know why the reputable company I have the quote from paired the M215 with a 290W module, but that is what they did.

[J.P.M.]

Understand that a module's STC rating will rarely be achieved in day/day operation and why, and you will be on the way to ending your confusion.

Read the PVWattts help/info screens, including the part about DC to AC size ratios. Also, download a free but somewhat outdated copy of "Solar Power Your Home for Dummies" from the net, or get an updated hardcopy at bookstores/Amazon for ~~ $20. Some of the scales of solar confusion will fall from your eyes.

All that said, an M215 micro seems undersized for a 290 STC Watt module. The 250 Watt micro seems like it would be a better choice for a 290 Watt module, but still undersized for a 330 W module.

[wexcellent]

Hi, I am a newb trying to design and install my own grid-tie system. I have seen this addressed in some other posts but it is still confusing to me. I have a quote to install Enphase M215 microinverters with Hyundai 290w modules from a reputable local company. The M215 spec sheet says that they are rated for 215W continuous power (225W peak). I watched an Enphase video on their newer M250 microinverters which said that they were best matched to a 330W module, even though they are rated for 250W. I don't understand why this is. I am assuming that when I go to PVWatts and put in my DC system size that this is based upon the rated wattage of the module I am using (290W). But how does this make any sense when the microinverter I am using has an output of 215W (AC)?

Thanks for your help, you guys rock!