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Topic: Solar Panel output exceeds specified Isc currents (Read 198 times) previous topic - next topic
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Solar Panel output exceeds specified Isc currents
I just installed a Go Power PWM-30 (2013 version) with an Eco-Worthy 100W  polycrystaline panel on a '88MB.
Since the Magnatek 6336 fuse panel was full I installed 30 amp tap on the 6 ga. battery wire terminal and set up a sub panel with a 30 amp main fuse. The Solar Controller(30amp) and the Propane/CO detector(5 amp) are fused from the sub panel(marine variety).  I have 10 ga. wiring to the solar panel with 30 amp fuses at each end.  I did this because the battery is on the right side and the converter and refrgerator vent are on the left side. 
As it was operating I notice the displayed current on the PWM controller was diplaying 6.7 amps. The Solar Panel Isc is listed as 6.11 amps at the mid day sun.  The displayed voltage was 12.7 to 14.4 volt range and the converter was turned off the night before with little overnight usage.  At that  point the solar panel is exceeding the Isc by 10%.

Will exceeding the Isc currents be an issue for the panel?


Rodney
1988 Mid Bath
Re: Solar Panel output exceeds specified Isc currents
Reply #1 –
When I installed solar on my camper, the monitor showed that I was charging the single marine deep cycle battery to beyond its capacity. I don't recall the exact numbers, but I was concerned.  The battery didn't get hot or bubble, but nevertheless I called the company that made the monitor and asked to talk to a tech.  I ended up talking to a very knowledgeable young man who confided that the feature showing capacity on the monitor wasn't accurate, but the rest of the monitor could be trusted.  I wasn't filled with confidence, but didn't have any problems either. The system worked fine for us for the next year and is still cranking out current for my daughter.

Good luck.

HD
2014 27 MB
Towd: Either the Jeep Wrangler or trailer containing the BMW R1200GS and 2 E-bicycles
Happy wife=Happy life
Re: Solar Panel output exceeds specified Isc currents
Reply #2 –
HD,
I have the same problem current for the children!!!

Being a Mechanical Engineer near Silicon Valley, I suddenly realized electronic components come in 20%, 10%, 5%, 1% tolerances.  So 10% over might not be too bad.
Rodney
1988 Mid Bath
Re: Solar Panel output exceeds specified Isc currents
Reply #3 –
Quote from: rodneyhelfrich  - 
I just installed a Go Power PWM-30 (2013 version) with an Eco-Worthy 100W  polycrystaline panel on a '88MB.
As it was operating I notice the displayed current on the PWM controller was diplaying 6.7 amps. The Solar Panel Isc is listed as 6.11 amps at the mid day sun. 
Will exceeding the Isc currents be an issue for the panel?
The wiring you install is adequate for 6-amp.
The slightly high amperage input is a good thing, assuming the controller is calibrated correctly.
The Go Power PWM-30 is a lower end controller and may not be as accurate as a more expensive model.
Testing the current flow with a accurate ammeter is your best way to verify the output reading.

Larry
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
Re: Solar Panel output exceeds specified Isc currents
Reply #4 –
Quote from: rodneyhelfrich  - 
The Solar Panel Isc is listed as 6.11 amps at the mid day sun.  The displayed voltage was 12.7 to 14.4 volt range and the converter was turned off the night before with little overnight usage.  At that  point the solar panel is exceeding the Isc by 10%.

Your solar charge controller is listed as a MPPT controller, so it tracks the maximum power point of the panel, and does a DC-DC conversion to maximize charge current for the actual voltage output. Your panel is not actually exceeding its maximum power current (nor the sc - short circuit current), but the current output of your charge controller is higher than its input current. To check, multiply the output current by the output voltage to get the output power. Then divide this by the input voltage from your panel to get the actual current output of your panel. This will be slightly off by the conversion efficiency loss of your charge controller.

Steve
2004 FL
2013 Honda Fit
 
Re: Solar Panel output exceeds specified Isc currents
Reply #5 –
Thank you for your input!
Rodney
1988 Mid Bath