From truck camping to an RV

[Amy@altE]

Bummer, I think I lost my weather window, lots of pre-production setup time was needed, and a thunder storm in moving in.

[Amy@altE]

Not a perfect test, but it was at least something. It's pretty overcast out, so I didn't record anything, but.... I have two 12V panels, one 100W and one 50W. I measured short circuit current (Isc) of each separately, and then wired in parallel. Again, lousy sunlight, but consistent. 50W measured .27A, 100W measured .59A. If you add them together, you get .86A. When I measured them wired in parallel, I got .85A, so virtually no loss. It does make sense, as they each have their own independent path wired in parallel. If the sun ever comes out again next week, I will do the same but with with them connected to PWM and MPPT charge controllers. Until then, just a data point.

[Electwistery]

Thanks Amy,
That was what I was suspecting when putting this system together , at this point I am trying to get my layout put together as far as where everything will go (fuses, cabling, breakers, inverter controller trimetric ect..) I also picked up some aluminum angle to make panel mounts from but still not sure how they will be put together yet

Thanks Again
Electwistery

[Amy@altE]

I've been promising a video showing mismatched solar panels for 3 months now, finally got some done, more coming soon. Spring weather did not cooperate with me. Go to YouTube and search "mismatched solar panels". I have same volts but different amps, and different volts and amps. I'll be doing different volts with same amps shortly (really).

[inetdog]

I've been promising a video showing mismatched solar panels for 3 months now, finally got some done, more coming soon. Spring weather did not cooperate with me. Go to YouTube and search "mismatched solar panels". I have same volts but different amps, and different volts and amps. I'll be doing different volts with same amps shortly (really).

Well produced videos, Amy!

One tiny observation about the first test:
When you did each panel individually the battery voltage was about 12.5-12.6. When you combined the panels in parallel the battery voltage was 12.8. So the wattage was 2% or so better than you would think if you compared only the amps going to the battery.


Any idea why, even with that correction, the wattage was lower than the sum?
Resistance of feed wires? More amps means more I²R losses.
Different efficiency of the MPPT CC at higher power?

[Amy@altE]

Sorry for the delayed answer. I'm not sure about the why of some of the results. Of course the solar resource (the sun) is variable, so it could be as simple as the sun wasn't as bright at that time. I didn't have my insolation meter going at the same time. I'm making improvements to my setup, and will be doing more videos soon that will include more test points and meters. We'll be doing some product bake-offs, and larger systems. It's going to be fun. I'll let you know when they are done.