Solar Panels With Bypass Diodes

[CA_Traveler]

This graph shows the positive effect of bypass diodes with clouds and leafy shade. There are 3 30V (about) serial panels with 3 bypass diodes each which results in each bypass diode controlling about 10V of panel output.

The morning starts with overcast clouds and full solar panel array voltage output (about 90V) in the limited light.

At 8:37 the clouds departed leaving leafy shade covering the panels resulting in 6 bypass diodes conducting and 3 of the panel sections producing power at 30V. As the shade changes on the panels the panel voltage increases to 40, 50, 60 and 70V.

At 9:27 all of the shade is off of the panels and the panel voltage is 90V. The MPPT controller continues to optimize the panel output as the sun continues to rise.




The panels are flat mounted and the sun is rising.

Note: Bypass Diodes have the effect of 9 independent serial panel sections. When there is a shadow on one section that section is bypassed – ie the effect is like a short for that section and it bypasses the amps of the other sections. One bypassed section results in 8/9 of the voltage, two sections in 7/9 of the voltage, etc, however the panel amps are not effected. I’ve seen charging with only 2 sections or 20V. Bypassed sections do not have to be in the same physical panel.

[CA_Traveler]

Updated graph.

[CA_Traveler]

agwil,

They are a common 30V type panel - ie 60 cells. The 3 panels are connected in series hence 90V. The controller is the Morningstar MPPT 60 which handles a maximum input voltage of 150V.

The actual panel is Cynergy 250W Endora Ultima Series sold by Solar Blvd.

My install.

[time2roll]

agwill, see my signature link as it is about the same.

[agwill]

Please sir if you would explain what type or brand of solar panels you are using. I have never heard of that high of voltage use before and what is the make of the controller. Just trying to learn. I understand three panels in parallel at 30 volts feeding controller with lots of current to charge battery's at 14 volts out. I am a little slow to understand.