Low output ?

porkfarm
porkfarm Registered Users Posts: 19 ✭
in General Solar Power Topics #1
Howdy all..

I have 14 Schott Poly 225W on a top of pole with enphase inverters. It seems that I have yet to get above 197 watts. Today is a clear bright day, not to hot 76..

The inverters are the 210's .

My question is..

Why am I not seeing over 200Watts per panel? Best peak that I have gotten so far is 2.8KW out of a 3.15 array...

I have hosed them down to make sure they are clean. All panels are very close in output..

Is this normal ??

Thanks for your help..
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Comments

  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: Low output ?

    Where/how is the Wattage being measured?

    With typical system losses, you're not doing too badly. Normally a panel's average output is less than its nameplate rating. Often it's only 80%. The inverters will use a few more Watts to run (Enphase are about 97% efficient at best, I think - don't hold me to it). You're getting an averaged (I'm guessing measurement type) output of 87%. That's not bad.

    The only tweak I can think of is to check your panel angle: http://www.macslab.com/optsolar.html
    You might squeeze a few more Watts out, or you may have to adjust the angle too much per season to make it worthwhile.

    Others here may have better insight to this.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #3
    Re: Low output ?

    Yep... For my GT system (xantrex central inverter type)--77% is a good typical maximum output for my system. The most I have seen (I do not have a logging system) is ~86% -- and that is not very often at all (we live in a temperate climate):
    • 3.15 kW * 0.77 = 2.4 kW
    • 3.15 kW * 0.86 = 2.7 kW
    I don't wash my panels more than once a year (2nd story mount and need large ladder to access).

    The other issue is the accuracy of the reported outputs. I have not heard anything about Enphase's accuracy--but for Off Grid Charge controllers it is not unusual for them to read 5-10% high, and at times even 30% high. (my Xantex is reported to be around +/- 2% accuracy).

    So--from the numbers you have given--it sounds like you are getting the expected amount of power from your panels/system.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • porkfarm
    porkfarm Registered Users Posts: 19 ✭
    #4
    Re: Low output ?

    I am getting the reading from the enphase equipment itself. enlighten and comm device. Seeing as it is a top of pole, I do swing it to try to chase the sun.. ( yes.. I am a shwvinger like the Goldmember... )

    Installer set the angle, but I will check on it tonight.. I think I can go from 15 - 65 in 10 increments. I should be at 65 this time of year... This is a powerfab rack.

    Thanks for the input.
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  • drees
    drees Solar Expert Posts: 482 ✭✭✭
    #5
    Re: Low output ?

    You really using the M210 inverters? The Enphase compatibility list lists the M190 or D380 for 98% of the panels listed, including your Schott 225s.

    Anyway, for temperatures in the upper 70s, panel output close to 200W sounds about right from what I've seen.

    I know that this install in Tuscon, AZ has 6 of the Schott 225s installed on the lower-left array - the rest are Schott 170s.

    http://enlighten.enphaseenergy.com/public/systems/tL4K292
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  • johnl
    johnl Solar Expert Posts: 30 ✭
    #6
    Re: Low output ?

    I see that the "real-word" CEC PTC rating of the Schott 225's is 198.4 watts (as opposed to the nameplate STC rating under ideal laboratory test conditions).

    http://www.gosolarcalifornia.org/equipment/pv_modules.php
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  • RCinFLA
    RCinFLA Solar Expert Posts: 1,485 ✭✭✭✭
    #7
    Re: Low output ?

    M210 spec is 96% "peak" efficiency. The "peak efficiency" is usually at 50% to 80% of rated power. Probably about 94% at 200 watts input.

    Derate panels for sun heating and you are at about expected level.
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  • drees
    drees Solar Expert Posts: 482 ✭✭✭
    #8
    Re: Low output ?
    RCinFLA wrote: »
    M210 spec is 96% "peak" efficiency. The "peak efficiency" is usually at 50% to 80% of rated power. Probably about 94% at 200 watts input.

    Derate panels for sun heating and you are at about expected level.
    Many test results are available here: http://gosolarcalifornia.ca.gov/equipment/inverter_tests/summaries/

    I'm surprised that the Inverter isn't throwing out all sorts of low-voltage errors given that the M210's min/max MPPT voltage is 31-50V and it's min/max start voltage is 38-62V, and that the Schott Poly 225 Vmpp is 26.9V and it's open-circuit voltage is 36.7.

    It appears to me that the Enphase M210 should not work well at all with that panel.

    The M190 on the other hand should be above 94% from at least 40-190W AC output.

    I'm guessing that the OP actually has a M190 and not a M210.
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  • porkfarm
    porkfarm Registered Users Posts: 19 ✭
    #9
    Re: Low output ?

    I could be wrong on the 210, but looking at the inverts on the enlighten side, the device names started with 1210. device type 800-00038-r08. One would think that you could get the stinking model number off the report... but no..;)

    I have not seen any of the connections, but the electrician quickly said something about 3 phase ???

    Overall, I am getting about 19kwh a day avg.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #10
    Re: Low output ?
    porkfarm wrote: »
    I have not seen any of the connections, but the electrician quickly said something about 3 phase ???

    Can't imagine why. Enphase output is single-phase, 240 VAC. It's doubtful your house is wired for 3-phase, unless you live in Poland or suchlike; some countries do have 3-phase connections to everywhere. Maybe he was just trying to impress you with his lack of knowledge. :p

    Or maybe he was saying it wasn't 3-phase. :D

    Or maybe I'm crackers. :roll:
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  • drees
    drees Solar Expert Posts: 482 ✭✭✭
    #11
    Re: Low output ?

    Enphase does make 3-phase 208V micro-inverters too - probably mostly used for larger utility scale installs.
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  • porkfarm
    porkfarm Registered Users Posts: 19 ✭
    #12
    Re: Low output ?

    I looked at the units last night... they are 190's not 210's. so the iverter number 210 has nothing to do with the model type.
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  • drees
    drees Solar Expert Posts: 482 ✭✭✭
    #13
    Re: Low output ?

    That makes a lot more sense.

    Anyway, your panel output appears to be normal. You won't get close to the panel's rating unless it's cool out (below 70*F), low humidity, no clouds, near solar-noon, and the panels are facing directly towards the sun.
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  • porkfarm
    porkfarm Registered Users Posts: 19 ✭
    #14
    Re: Low output ?

    Great ! Thanks for the info.. I bet I come into those conditions in a few months.
    I will post results if I ever crack better than 2.9.. good to know that I am in range..

    Thanks again everybody..
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