Solar Panel Shadows and Bypass Diodes
The following data was collected from my 3x250W flat mounted solar panels on 1/16/15 in my storage area in the Phoenix area. The graph shows the significant transition as the sun just covers the 3rd r...
Forum Discussion
remember each cell is approx .5v ( i think )
36 cells equal 18v
shaded cells produce NO voltage, its very easy, to have a panel producing voltage too low to charge a battery, say only 10v or even 12~13v, won't charge anything unless that battery is near dead
but two panels in series making 10v each at DAWN, equals 20v into the controller
this means the controller can start charging the battery, even if its only an amp or two
this requires bypass diodes internal to the panel around the cells, so the amps go around the non producing cells
this is the morning "low light", tree shade , advantage of series panels,
your not going to get mPPT gains in morning, but you get the controller "waking up" before it would do so with PWM and parallel panels all showing 10v
or under a canopy, or trees
the disadvantage is when a series panel in the shade shuts down a whole string, because they are wired multiple panels for high voltage
i think i stated all that correctly
i know somebody will..be sure to let me know i got it wrong
36 cells equal 18v
shaded cells produce NO voltage, its very easy, to have a panel producing voltage too low to charge a battery, say only 10v or even 12~13v, won't charge anything unless that battery is near dead
but two panels in series making 10v each at DAWN, equals 20v into the controller
this means the controller can start charging the battery, even if its only an amp or two
this requires bypass diodes internal to the panel around the cells, so the amps go around the non producing cells
this is the morning "low light", tree shade , advantage of series panels,
your not going to get mPPT gains in morning, but you get the controller "waking up" before it would do so with PWM and parallel panels all showing 10v
or under a canopy, or trees
the disadvantage is when a series panel in the shade shuts down a whole string, because they are wired multiple panels for high voltage
i think i stated all that correctly
i know somebody will..be sure to let me know i got it wrong
