ST2000 and solar panel output.


Gus Spagnotti:
I need some help, I have a older ST2000 Suntie with 4 24vdc Sharp 165w panels 2 pv input legs into the inverter.
For a total input wattage of 165w x 4 = 660w right? The inverter only display 300w - 320w
even on the best solar days. I live in Nebraska with big blue skies, no fast moving clouds. I'm I wrong I my math?? Any thoughts would be Great.

roland funk:
do you have a small Voltmeter to check the Voltage of your PV modules ??
According to description the ST2000 has 52-85V DC input and 240V AC output.
This requires in your case 2 strings each of 2 serial connected PV modules. So the combined Voltage per string should be 2*34 Volt rated (2*43 Volt open circuit) if there is no wrong wiring.
So half the performance could be lost if:
(1)you join all 4 modules serial so excess (doubled) DC Voltage is wasted.
(2)The AC output of ST2000 is 240V (I am not from the US so no idea where/when you have 120V and when 240V in the grid) - is there some output Voltage selection in your ST2000 ??
No idea what happens if your input DC Voltage or output AC Voltage is just doubled and therefore 50% power wasted -- If this is possible at all and the inverter is not blowing up or shut down before.
--- Sorry just some stupid ideas and more questions than answers .....

Thomas Allen Schmidt:
Curious, have you changed out this ST2000 in this post for the ST 1500 that you mentiond in your recent posting?
I have not been able to locate documentation on ST's only STXR's.
What does your installation/owners' manual say is the minimum and maximum Vdc input?
Is it possible that the display is showing the PV source wattage one "leg" at a time? Or is it supposed to show the total of all PV source input wattage?
I have a tendency to pride myself from time to time on being able to troubleshoot problems. As an eletrician, I do service work in residential, commercial, and industrial.
The differance here is I can't be there in person to look at your picticular troubles.
But I can tell you that part of my success with troubleshooting relys on process of elemination and dogged determination.
Am I correct in asummimg the there are two "legs" of PV soure input? and that both of these are producing there rated or close to there rated output when disconnected from the inverter?
Is the inverter mounted in a place where cool than ambient air can flow accrossed its heat sinks? Good documentation is a big plus when dealing with a manufactured electronic/electrical product.
Are the PV source wire sizes correct for the distances between PV array, combiner, disconnect, and inverter? What type of wire is it? THHN, USE2, etc. , etc.


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