Usefulness Of MPPT Technology
This isn't a trick question. I wish to take a "Short Course" in the reality versus hype of MPPT control... Users who have MPPT and can report real-life experience... Let's say I get a pair of panel...
Forum Discussion
The biggest factor will be the approximate 16% reduction in panel wattage output due to the 90°F temp. Assuming 1 kW/m^2 irradiance and zero angle of incidence, panel output would be about 302 watts. As PT said, (sufficiently) large wire between panels and MPPT controller is critical. Assuming a 2% loss between panels and controller and a controller efficiency of 96% (most MPPT controllers will be 95% to 98%), controller output will be 302*.98*.96 = 284 watts. That would equate to 23.2 amps at 12.25 volts.
Doubling the panel output voltage will allow you to use smaller wire between the panels and controller or will reduce losses for the same size wire. However, the MPPT controller is slightly less efficient when converting from higher voltage to lower output voltage.
The effect of the angle of sunlight or angle of incidence is independent of type of controller. It has the effect of decreasing the size of the panel or decreasing the apparent irradiance. The calculation is the cosine of the angle of incidence. At 0° (pointed right at the sun) the panel has full output. At 60°, the panel has only 50% output.
I have had only one brand of controller so I can't comment on different brands. My setup is almost the same size as your example and I have quite often gotten more than 24 amps, but I don't often see 90°F in Colorado.
Doubling the panel output voltage will allow you to use smaller wire between the panels and controller or will reduce losses for the same size wire. However, the MPPT controller is slightly less efficient when converting from higher voltage to lower output voltage.
The effect of the angle of sunlight or angle of incidence is independent of type of controller. It has the effect of decreasing the size of the panel or decreasing the apparent irradiance. The calculation is the cosine of the angle of incidence. At 0° (pointed right at the sun) the panel has full output. At 60°, the panel has only 50% output.
I have had only one brand of controller so I can't comment on different brands. My setup is almost the same size as your example and I have quite often gotten more than 24 amps, but I don't often see 90°F in Colorado.
