Fronius IG4000 Inverter

poleikleng
poleikleng Solar Expert Posts: 29 ✭
in General Solar Power Topics #1
I have a previous 2.88 kW ground mount array with a Solectria PVI2500 inverter and 16-180 watt Evergreen panels. I just had a 3.68 kW array installed using a Fronius IG4000 inverter. Under the same conditions the 2.88 array AC output is approximatley 2300 watts (noon time). The new array is also ground mount (16-230 watt Yingli panels) and the Fronius AC output is approximately 1950 watts. Is this a concern. Thanks

Poleikleng
· Share on Twitter

Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #2
    Re: Fronius IG4000 Inverter

    Can you measure the Varray and Iarray (middle of the day)?

    If you have two parallel strings of 8 panels each--Can you measure the current in each string (with a DC Current Clamp Meter)?

    Or disconnect one string, operate, then change over to the other string and measure.

    Since I am lazy--what is the Vmp/Imp of the array (panel specs). And what is the input rating of the GT inverter?

    What is your average high ambient air temperature?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
    · Share on Twitter
  • poleikleng
    poleikleng Solar Expert Posts: 29 ✭
    #3
    Re: Fronius IG4000 Inverter
    BB. wrote: »
    Can you measure the Varray and Iarray (middle of the day)?

    If you have two parallel strings of 8 panels each--Can you measure the current in each string (with a DC Current Clamp Meter)?

    Or disconnect one string, operate, then change over to the other string and measure.

    Since I am lazy--what is the Vmp/Imp of the array (panel specs). And what is the input rating of the GT inverter?

    What is your average high ambient air temperature?

    -Bill

    Bill,

    I do not have a DC current clamp meter and I do not have the skills necessary to take the measurements that you describe.

    Evergreen 180 watt panels: Vmp 17.1; Imp 10.53 (standard test conditions)

    Yingli 230 watt panels: Vmpp 29.5; Impp 7.8

    Today's ambient air temperature: 67 degrees

    Fronius IG4000 input rating: Max. DC input voltage 500 V or Max. usable DC input current 26.1 A; Recommend PV power 3000 - 5000 Wp (not sure this is what you specified?)

    Bill, in your opinion is the problem more likely the inverter or the panels?

    Thanks for your repsonse
    · Share on Twitter
  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    #4
    Re: Fronius IG4000 Inverter

    http://www.solarelectricsupply.com/Solar_Panels/Yingli/YL230P-29b.html

    http://www.fronius.com/cps/rde/xchg/SID-64B73706-38D0514C/fronius_usa/hs.xsl/2714_1477.htm

    It would have to be 8 x 2 on the stings ... I'd say that one of the strings isn't working or is wired wrong. Since you can't make the measurement, get the installer out and he needs to verify both strings are functional
    · Share on Twitter
  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #5
    Re: Fronius IG4000 Inverter

    From Solar Guppy's link to the Fronius link:
    Operating DC voltage range
    150 - 450 V

    Basically, 8x29.5=236 Vmp-array STC (standard conditions). So the input voltage looks OK.

    I agree with Solar Guppy--It looks like one string is not working (no current).

    I don't know about the Fronius--but many inverters will give you the Array voltage and current that the inverter input is "Seeing"... See if you can get that from your inverter.

    At some point--If you are going to do your own debugging--a "good enough" combination DMM / AC/DC current clamp meter like this one, is a good investment for $60. DC current clamps are very handy for working around DC power.

    If you have access to the DC wires (at the array, or else where), clamping the current meter around a single wire can tell you a lot about how each parallel connected string is working.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
    · Share on Twitter
  • poleikleng
    poleikleng Solar Expert Posts: 29 ✭
    #6
    Re: Fronius IG4000 Inverter
    BB. wrote: »
    From Solar Guppy's link to the Fronius link:



    Basically, 8x29.5=236 Vmp-array STC (standard conditions). So the input voltage looks OK.

    I agree with Solar Guppy--It looks like one string is not working (no current).

    I don't know about the Fronius--but many inverters will give you the Array voltage and current that the inverter input is "Seeing"... See if you can get that from your inverter.

    At some point--If you are going to do your own debugging--a "good enough" combination DMM / AC/DC current clamp meter like this one, is a good investment for $60. DC current clamps are very handy for working around DC power.

    If you have access to the DC wires (at the array, or else where), clamping the current meter around a single wire can tell you a lot about how each parallel connected string is working.

    -Bill

    Bill,

    Thanks for your response. I have contacted the installer. I will let you know the outcome. Thanks again for your help.

    Poleikleng
    · Share on Twitter
  • poleikleng
    poleikleng Solar Expert Posts: 29 ✭
    #7
    Re: Fronius IG4000 Inverter

    Bill,

    I have a DC/AC current clamp meter, what should I look for regarding current when I read the meter?

    Poleikleng
    · Share on Twitter
  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #8
    Re: Fronius IG4000 Inverter

    First, with the meter, experiment with setting up the DC current mode.

    DC meters have some sort of zeroing function because they use a transistor that is sensitive to magnetic fields, so it drifts around every 1/2 to several minutes from zero. Experiment on your car and its battery--Turn on the headlights and see that you have a reasonable current flow (probably close to 10 amps). Note that when you flip the meter 180 degrees on the cable, the +/- sign will change (meter will indicate direction flow of current).

    On your solar array... You should have two strings. Measure the current flow on each string... They should be within ~10% of each other (i.e., 5 amps and 4.5 amps--or closer). If off by much more than that, you have significant problems.

    You need to clamp one wire at a time--if you clamp two wires, you will get the sum of the current... For example, if you clamp the two + wires of your array, you may get 9.5 amps total (using the above example). If you clamp the +/- wires of one array--You will get 5.0a-5.0a=0a -- The current can add or subtract from multiple wires--depending on direction of current flow through the clamp.

    Current value wise--near high noon, clear day, panels pointing with in 10 degrees of the sun--you should see 80-90+% of Imp of the array (string). At times, you may see near 100% of Imp.

    If you see 1/2 or less of what you expect--you have a problem.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
    · Share on Twitter
  • poleikleng
    poleikleng Solar Expert Posts: 29 ✭
    #9
    Re: Fronius IG4000 Inverter

    Bill,

    We haven't seen the sun in a week but today at 2:00 pm the sun appeared briefly. I put the meter on one our Evergreen 200 watt panels, Imp 11.05 rated and the meter read 12.38 amps, I then put the meter on one of the Yingli 230 watt panels, Imp 7.8 rated and the meter read 4.07 amps. Clearly a problem?

    Poleikleng
    · Share on Twitter
  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #10
    Re: Fronius IG4000 Inverter

    I would say it appears so... Can you measure the current for each "string"--or was that total current (afternoon, some clouds about)? If you can measure the current in each string--that will tell you if one string is having problems or if it both.

    Current Readings are fairly temperature independent if driving a short circuit.

    However, the current is more variable with changing voltage.

    What are the Vmp's of the Evergreen vs Yingli panels? I believe the arrays should look like:
    • 8 x 17.1 volts = 136.8 volts
    • 8x 29.5 volts = 236 volts
    My 354 volt Vmp array runs between ~310-370 volts most days (hot to cold).

    The GT controllers have MPPT (maximum power point tracking) inputs that vary the input current to set the array voltage to maximize the:
    • Power max = Volts max power * Current max power
    You could be having solar panel problems or inverter MPPT tracking problems--it is hard to tell...

    If you can measure the current in each string--and the current differs (i.e., one string is 3.5 amps and the other is 0.7 amps--then there is a problem with the panels or array wiring.

    What voltages are you seeing for your arrays at the GT input?

    How are they wired (I think it is 8 panels in series, 2x stings for 16 panels total, on each GT inverter)?

    Vmp during the day is controlled by the charge controller and tends to go up when cool (less sun, cold and windy) and down when hot sun, hot weather, and little wind. If you see something else happening--It may be a GT inverter problem.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
    · Share on Twitter
  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    #11
    Re: Fronius IG4000 Inverter

    You need to measure each of the two strings on the Fronuis, not compare between the two seperate solar systems.

    On the Fronius, measure the DC current at each positive wire at the solar input of the inverter.

    What happened to the installer? wasn't he suppose to come on and verify the series strings?
    · Share on Twitter
  • poleikleng
    poleikleng Solar Expert Posts: 29 ✭
    #12
    Re: Fronius IG4000 Inverter
    BB. wrote: »
    I would say it appears so... Can you measure the current for each "string"--or was that total current (afternoon, some clouds about)? If you can measure the current in each string--that will tell you if one string is having problems or if it both.

    Current Readings are fairly temperature independent if driving a short circuit.

    However, the current is more variable with changing voltage.

    What are the Vmp's of the Evergreen vs Yingli panels? I believe the arrays should look like:
    • 8 x 17.1 volts = 136.8 volts
    • 8x 29.5 volts = 236 volts
    My 354 volt Vmp array runs between ~310-370 volts most days (hot to cold).

    The GT controllers have MPPT (maximum power point tracking) inputs that vary the input current to set the array voltage to maximize the:
    • Power max = Volts max power * Current max power
    You could be having solar panel problems or inverter MPPT tracking problems--it is hard to tell...

    If you can measure the current in each string--and the current differs (i.e., one string is 3.5 amps and the other is 0.7 amps--then there is a problem with the panels or array wiring.

    What voltages are you seeing for your arrays at the GT input?

    How are they wired (I think it is 8 panels in series, 2x stings for 16 panels total, on each GT inverter)?

    Vmp during the day is controlled by the charge controller and tends to go up when cool (less sun, cold and windy) and down when hot sun, hot weather, and little wind. If you see something else happening--It may be a GT inverter problem.

    -Bill

    Bill,

    Thanks for the response. With my limited knowledge my goal was to try and confirm there was a problem with the array/inverter. The installer was waiting for full sun conditions to test the array under load and he should be here early next week. We have had nothing but rain all week. I sense there is a problem but unfortunately I do not have the skills to trouble shoot the system.

    The array has a 4 x 4 grid. I did measure all the DC current on each panel and the worst conditon the measurements varied by .6 amps between the - and the + reading.

    I will let you know next week what the problem was.

    Poleikleng

    Hopefully I can learn some useful
    · Share on Twitter
  • poleikleng
    poleikleng Solar Expert Posts: 29 ✭
    #13
    Re: Fronius IG4000 Inverter

    It appears I have a bad inverter, will confirm this Tuesday with the manufacturer.

    Poleikleng
    · Share on Twitter
  • poleikleng
    poleikleng Solar Expert Posts: 29 ✭
    #14
    Re: Fronius IG4000 Inverter

    Confirmed, the inverter will be replaced.

    Poleikleng
    · Share on Twitter

Categories