Can M215 micro inverter deliver more than 215 W AC?

[LeRoy]

I've looked at several threads here and there seems to be conflicting information on this subject.

My main concern is whether an M215 paired with a 250W (STC) panel can deliver more than 215 watts of power. Is it a moot point since a 250W (STC) panel will rarely, if ever, deliver more than 215W?

Thanks.

[bonaire]

I think the max is about 215-220W AC. It seems normal to go with 215's with bigger modules. That way, when you're not at the peak, the higher-efficient module can gather more than a module that has a max rating of say 230W on a 215 microinverter. If a 250W module costs the same as a 240W, get the 250W, obviously. Enphase calls this "oversizing" the module. Enphase says to use a max module DC peak power rating of 270W per module.

There are larger 72-cell solar pv modules in the 300W to 330W output capacity. For those, you can choose PowerOne 300W micro-inverters, or perhaps their 250W microinverter for some of the 260W to 280W 60-cell modules. Even string inverters are typically oversized a bit. You can setup 7500W of modules on a 6500W inverter, for example. I have 8.16KW of modules running through two PowerOne Aurora 3.6 (max AC output is about 3840W as they are 16A * 240V max AC). On my inverter panels, I have seen 4011W max but I believe that may be the DC power and not what is on the AC side.

Enphase says "output power: 215W" http://enphase.com/products/m215/ but that is the maximum power, not constant, of course.

The 215 may allow higher 220W - maybe some users with Enphase installed can comment on what their monitoring software is showing?.

The older 190 microinverter clipped at 199W.

If you have no shading issues and can have a straight array without funky mixed angles, a string inverter may still be a noticable lower price per Watt installed, for a project, versus micro-inverters. If you save $500-1000 on the overall installation, I can't see ever getting that back in extra electricity as marketed by the micro-inverter companies. Some string inverters, like the PowerOne Auroras, have two MPPT controllers within rather than one so they are in between the single "combined string" inverter and micro-inverters for efficiency potential. It's all about price of the system, return on investment and the viability of the companies standing behind the products (whether they will be around to support the warranties should a part fail). Enphase has lots more debt and is not a profitable company yet. PowerOne has no corporate debt. I went with PowerOne for that reason. They're #2 to SMA in worldwide market share.

[Naptown]

It is rather a moot point.
With dirt, weather, heat etc you will generally only ever get about 90% of the STC out of a panel.
Now consider that the inverter is 95% efficient and the 215W rating is based on the OUTPUT not the input, do the math.

[BadgerBoy]

My M215's produce 225 watts and when its sunny all day and cold, they clip for 3 hours somedays. Take a look: https://enlighten.enphaseenergy.com/...stems/32Ks9027

[Naptown]

My M215's produce 225 watts and when its sunny all day and cold, they clip for 3 hours somedays. Take a look: https://enlighten.enphaseenergy.com/...stems/32Ks9027

Without knowing more about your system it is hard to tell from the Enphase site exactly what is going on.
So Panel make and wattage and orientation of the arrays Note you have arrays in several orientations. It is hard to tell as we cannot see the individual panel output per panel on an hourly basis from the link provided. (no permission

[BadgerBoy]

Not much sun the last couple days. Maybe you are not familiar with the Enphase system. You should be able to see real time production continuously throughout the day. The 6 panels on the right are Trina 220's with M190 inverters. The West array are 8 Helios 240's on the left and 4 Helios 250's on the right with M215's. When its sunny at this time of year, they actually clip for 4 hours, the M215's at 225 watts, and the M190's at 199.

[BadgerBoy]

oh, and orientation. They are at 173° azimuth and at 70° vertical for the winter. The reflection from the snow on the field in front of them helps. The 173° is optimal for our location as verified by PVWatts. We have often morning sun and afternoon clouds. Also, when you think about it, panels are cooler in the morning and can produce more because of that, so a southeast bias is beneficial. We lower the vertical angle in the spring. My panels are also on PVOutput.org if you look for them under the name "Power from Above".

[Naptown]

oh, and orientation. They are at 173° azimuth and at 70° vertical for the winter. The reflection from the snow on the field in front of them helps. The 173° is optimal for our location as verified by PVWatts. We have often morning sun and afternoon clouds. Also, when you think about it, panels are cooler in the morning and can produce more because of that, so a southeast bias is beneficial. We lower the vertical angle in the spring. My panels are also on PVOutput.org if you look for them under the name "Power from Above".

That is the reason they are clipping. For 90+% of the world this is not an option. The albeido effect on cold panels is driving the output up way beyond the rated output of the panel. (Remember how they are rated at STC) with the reflection from the snow you could be getting upwards of 1600-1800 Wm² irradiance on them.

[peakbagger]

I will testify that cold clear winter days with snow on the ground clips my 2000 watt Fronius central inverter at 2102 watts (per the readout). My max voltage also can be pretty interesting first thing in the AM. I expect more than few first time designers have blown it on their string voltage calculations by not accounting for the lowest temp.

[Naptown]

I remember taking a code class from John Wiles a few years ago. He commented that they had a night where the temps in NM were 15d colder than the record previously. He was expecting a number of cooked inverters.

[Vic99]

Here in MA, I've had emphase's 215 microinverters on 25 Suniva 255W panels since October. They seem to clip at 225, although I had a single reading of 226Wf in early February. Seems that the reflectivity of snow drives up production. My most productive day has been Feb 15th.

[leepoffaith]

I have 40 250w Suniva Panels with microinverters that were just installed December 1st. I've had a few instances where 1 or 2 panels will show 226w production, but in general they max out at 225w. I'm in Florida, so I have no snow to reflect, but cool weather does help. I had the best day of production thus far (54.7 kWh) on February 17 because it was roughly 38 degrees in the morning and only got up to about 55 during the day. There wasn't a cloud in the sky this day. 25 of my panels face almost exactly east and the other 15 face almost exactly south. If you have any questions, let me know and I'll try to answer them the best I can.