Sales Engineer from Boulder, CO

[crxvfr]

Enphase ....

Every time I turn around I hear of a new gadget. Can you use these microinverters on more than one panel so long as you don't go past voltage or amperage limits? Say you have an array of 42 panels that are in columns of 3. 14 columns. Can you have a microinverter for each column? If you have MPPT microinverters, can you use them with a charge controller? ...or are they only for net metering.

EDIT ADD: Nevermind, found out via google.

[trbizwiz]

Hey there - just wanted to let you know my array is CSI 230s, and I do see outputs of 199 watts from the Enphase M190 micro-inverters. It's been cloudy and hot this week along our area of the Front Range. I am wondering if my panels are a bit dusty but I think the lessened output is a result of the clouds and heat. Perhaps in September the numbers will inch back up.

Csi is Canadian solar right?

[Walt_Solartown]

Hey there - just wanted to let you know my array is CSI 230s, and I do see outputs of 199 watts from the Enphase M190 micro-inverters. It's been cloudy and hot this week along our area of the Front Range. I am wondering if my panels are a bit dusty but I think the lessened output is a result of the clouds and heat. Perhaps in September the numbers will inch back up.

[Mike90250]

.....

@Walt are these in a shady area? Are they dirty?, Do they not point true south, or is the angle wrong? Why would you suspect the output is lower than the projected 180 watts?

They are roof mounted I suspect. And you get the sun angle that the roof is at.
For fixed arrays, there will be about a 15 minute "sweet spot" daily, as the sun is most perpendecular to the array. You can't change the roof angle/pitch, or the house orientation, so the panel's sweet spot may be at 2:30 pm or 11:45am

My west faceing GT array peaked about 3pm. I have max power for about 6 days each June, then it degrades.

[trbizwiz]

Maybe I am late in the game and have not read all the post. If you use an enphase inverter for each panel, then mixing panels should not be a problem. It is the mixing of panels in strings and parallels is where the problem occurs.

OK with that said if you have a 230 watt panel, and the most you have ever seen it produce is 130 watts something is wrong. 230 watts is likely the STC rating which is not real. However the PTC or real world power should be around 80 to 90% of the STC rating. So if you have a 230 watt panel. I would expect to see 185 to 200 watts at solar noon on a bright sunny day.

The 130 watt number comes from walts post above. If you click on the link it takes you to the enphase website. The 10 panels ranged from 127 to 131 at around noon mountain time.

@Walt are these in a shady area? Are they dirty?, Do they not point true south, or is the angle wrong? Why would you suspect the output is lower than the projected 180 watts?

[Sunking]

Maybe I am late in the game and have not read all the post. If you use an enphase inverter for each panel, then mixing panels should not be a problem. It is the mixing of panels in strings and parallels is where the problem occurs.

OK with that said if you have a 230 watt panel, and the most you have ever seen it produce is 130 watts something is wrong. 230 watts is likely the STC rating which is not real. However the PTC or real world power should be around 80 to 90% of the STC rating. So if you have a 230 watt panel. I would expect to see 185 to 200 watts at solar noon on a bright sunny day.

[trbizwiz]

Probable not as close as you think. This is why you should never mix panels.

Even with their individual inverters?
Do you think if these were arrays of 10 panels each, that one array would have significantly different numbers than another other than the factor of 5 (currently 2 panels changing to 10 panels makes the factor of 5)
Or , would you think this would illustrate the weakness of the enphase single inverter for single panel design as opposed to mounting panels in a string and connecting to a central inverter? I have been under the impression that enphases design was more efficient than the other, maybe this disproves that??

[Sunking]

The 130 numbers are off of Walt's array as what it is producing right now using some 230 watt panels among other wattage rated panels in Colorado. Ironically all the panels regardless of rated wattage are very close in output,

Probable not as close as you think. This is why you should never mix panels.

[trbizwiz]

The output per panel is as per standard conditions - the right way to do things.

It is up to the consumer (since they are assuming a minor engineering function) to understand how standard conditions relate to the real world.

Your 230 to 130 numbers are not correct - the numbers have been supplied by Mike previously.

The planet green thing shows someone's mixed up way of trying to be different and by that person's definition - better. Reminds me of an old song, 'wishing & hoping'!

The 130 numbers are off of Walt's array as what it is producing right now using some 230 watt panels among other wattage rated panels in Colorado. Ironically all the panels regardless of rated wattage are very close in output, with the lowest rated panels producing the highest wattage. Since it was around noon mountain time when I saw those numbers, I have to assume that is peak for this time of year. So I am guessing mathematically Mike is correct, and I am guessing circumstantially Walt's enphase report is correct.
The Canadian snow theory seems to add credence to the planet green guys theory.
Please don't mistake my comments as argumentative. I am just really trying to make sense of everything.

[russ]

The output per panel is as per standard conditions - the right way to do things.

It is up to the consumer (since they are assuming a minor engineering function) to understand how standard conditions relate to the real world.

Your 230 to 130 numbers are not correct - the numbers have been supplied by Mike previously.

The planet green thing shows someone's mixed up way of trying to be different and by that person's definition - better. Reminds me of an old song, 'wishing & hoping'!

[Mike90250]

It appears, that 230 watt panels only output around 130 watts. So much for truth in advertising.
What sort of conditions would it take for those 230's to output anywhere near their posted wattage?

Hold the panels at 70F, use a calibrated 1 Sol flash tube. (about $80,000)
Flash the panels. They will output 230W!

Or live in Canada, at -30F, with reflection off snow, you will get 260W, or more.

Heat, haze and oblique sun angle are the enemy.

[trbizwiz]

very interesting results

I guess this fully explains my other question I have been asking in other posts, about using the M190 on 230 watt panels. It appears, that 230 watt panels only output around 130 watts. So much for truth in advertising.
What sort of conditions would it take for those 230's to output anywhere near their posted wattage?
Even so it appears your monthly average will be in the 330 KWH range. That seems decent. That would off set my utility bill by $31. I can only imagine what that system could do if it produced peak wattage!!

Side note, I saw a show on planet green one time and the guy had an overhead panel mounted face down, then he had a solar reflector on the ground facing the inverted panel. He had a low tech sun tracking system that somehow used buckets of water to cause the reflector to track the sun and project the solar energy (light) onto the solar panel. He claimed it made the panel much more efficient. He demonstrated it by attaching a fan to the panel facing directly at the sun, then he inverted the panel facing the solar collector and the fan sounded and looked to run much more quickly. He gave percentages of how much more or less efficient either setup was, but I am terrible at remembering intricate statistics.

[Mike90250]

......
If you're interested in Enphase check out this installation recently completed - we put up 2 Sharp 224s, 2 Solon 220s, 2 Schott 220s, 2 Trina 230s and 2 Yingli 230s. The Yinglis weren't comissioned on the same day so their lifetime output is a bit skewed. I find the daily output most telling. http://enlighten.enphaseenergy.com/p...stems/K7595568 - perhaps this will sway people toward one panel over another though it is not entirely scientific. It is what we did to understand some of the differences between panels.

Very nice comparison between panels. I like being able to run the daily slider and see the power as the panels wake up. I'm amazed they all track so well (from what I can see).

[trbizwiz]

That's a great idea. Giving people the chance to see different panels in action in the same environment. I'll take a look myself.

[Walt_Solartown]

Hello Russ - I'm fine to call myself a salesman. I've taken a good bit of training but as I do not have an engineering degree I don't want to mislead people. My previous career was 'QA Engineer'. I've installed several arrays but won't support my family on the roof alone - which is why I started selling them.

If you're interested in Enphase check out this installation recently completed - we put up 2 Sharp 224s, 2 Solon 220s, 2 Schott 220s, 2 Trina 230s and 2 Yingli 230s. The Yinglis weren't comissioned on the same day so their lifetime output is a bit skewed. I find the daily output most telling. http://enlighten.enphaseenergy.com/p...stems/K7595568 - perhaps this will sway people toward one panel over another though it is not entirely scientific. It is what we did to understand some of the differences between panels.