panel wire AWG to controller
Ok so the ts-MPPT-60 is on its way, I put the card board cut outs on the roof just to make sure the panels fit as I thought and now on to more planning. I check a few voltage drop calculators for t...
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Here’s another example of the effective use of serial panels and bypass diodes from data that I collected at the rig storage area. The 3x panel Voc is 90V (actually 91.74V). With full shadows on 2 panels and 1/3 of the third panel I was getting 16V from the array and the battery was being charged. That’s expected as each panel has 3 bypass diodes so 7 diodes were conducting for about 3.5V (using 0.5V per diode) loss. So the expected 20V panel output (1/3 with a shadow) is 20-3.5=about 16V+.
Then with full sun on one panel the array voltage was 28V+ as expected. This should be equivalent to a test involving turning the 2 panels away from the sun. To me when dealing with 30V panels the loss of a maximum of 1.5V for 3 bypass diodes is well worth the tradeoff for the additional 10V or 20V with partial shading on a given panel.
For the above test Click Here.
From my research I decided to mount the panels high enough to eliminate any significant rig shadows. With basic north south rig orientation there are no shadows on my flat mounted panels. With the worst case rig orientation there are no shadows for any sun elevation above 10 degrees at sunrise or sunset, so rig shadows are insufficient.
And while not planned I’ve now collected data from 2 different shadow situations, both leafy shade and full shade and both show the positive effect of bypass diodes.
Then with full sun on one panel the array voltage was 28V+ as expected. This should be equivalent to a test involving turning the 2 panels away from the sun. To me when dealing with 30V panels the loss of a maximum of 1.5V for 3 bypass diodes is well worth the tradeoff for the additional 10V or 20V with partial shading on a given panel.
For the above test Click Here.
From my research I decided to mount the panels high enough to eliminate any significant rig shadows. With basic north south rig orientation there are no shadows on my flat mounted panels. With the worst case rig orientation there are no shadows for any sun elevation above 10 degrees at sunrise or sunset, so rig shadows are insufficient.
And while not planned I’ve now collected data from 2 different shadow situations, both leafy shade and full shade and both show the positive effect of bypass diodes.
