Amp Question

Hi All. New here. I have 14 solar panels, each rated at 240 watts (30.2 Vmp, 7.95 Imp) being fed into a Frontius Primo 6000 Watt grid tie inverter. With the sun perpendicular to the panels, I've only been able to get 800 watts at the most from the inverter readout. The usual is anywhere from 300-500. I have tested each panels voltage and get ~25 to 27 volts. I should be producing at least 3000 Watts. The cable run from the panels to the inverter is ~60ft. I also used a DC amp clamp on one of the cables as it goes into the house and was getting around 0.9 amps. This is baffling me. Is it possible that a panel can produce its rated voltage but not its rated amps. Our house uses a lot of amps so the need is there I just don't understand. I would sincerely appreciate any help.
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https://www.solar-electric.com/fronius-primo-6000-watt-grid-tie-inverter.html
14x 240 watts (30.2 Vmp, 7.95 Imp)
Are the panels wired 1x series string of 14 panels?
-Bill
Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.
5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
To me, assuming there is no shading and they are hooked up in a single string that you have a panel with a couple bad internal strings or diodes, I think normal 60 or 72 cell panels are made up of 3 strings of cells with diodes;
A single panel with bad strings will limit the whole string of connected panels.
- Assorted other systems, pieces and to many panels in the closet to not do more projects.
Bill. Thanks for the reply. That is the correct inverter. The 14 panels are wired as one string. The inverter salesman advised me to use one string as the inverter required a certain amount of voltage to start. Two string would not be enough.
There is no shading whatsoever on the panels.
Photowhit, I appreciate your comment. How would I troubleshoot the strings or diodes? If each panel puts out the rated voltage, could I still have a bad panel?
Thanks again, I do appreciate the input.
Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.
5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
I'm trying to think of something like a 24 volt DC motor, I think some battery tool motor might work, but they don't draw enough wattage unless under load them selves. Something that you could take with you to put a load on the panel and measure output.
I'm pretty stumped, They make specific DC heating elements for diversion loads, some sort of pure resistance load, like a heating element. An AC element would run at about 1/16th the wattage with 30 volts DC than 120 volt AC so even a 1500 watt heater wouldn't draw enough to test a panel.
I guess just shorting them out, the wire will act as a heating element, and measure the current circulating. I understand the current will flow, and I can't understand why this wouldn't be a valid test, but don't know. There really isn't much resistance.
Any one have any ideas?
- Assorted other systems, pieces and to many panels in the closet to not do more projects.
1) Voc with DMM in Volts mode
2) Isc with DMM in Amps mode
The bad panel will be obviously different than the good panels.
No other external "load" is required
Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
Also, any shading, including power lines, can dramatically reduce output.
If your rated Vmp~30 volts, then Voc should be closer to ~35 volts.
What is the brand/model of your panels?
-Bill
BB. The DC voltage coming into the inverter is ~600. I was wrong in my earlier comment that the panels put out around 25 V. They put out about 32V. No shading. The panels are:
UpSolar UP-M240P
Vmp 30.2
Imp 7.95
Voc 37.6
Isc 8.40
- 30.2 volts * 14 panels = 423 volts (cold/bright day)
- 30.2 volts * 14 panels * 0.81 hot panel derating = 342 volts (hot/noontime sunny day)
Your system should not be reading 600 vdc at all during anything near normal operation.-Bill
Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter