Ask The Solar Expert Barry Cogbill!
My friend Barry now has a weekly radio program on KSRO radio. The station is based in Sonoma County. It’s called “The Clean Energy Show with Barry Cogbill” :-) He talks about solar power, energy efficiency, green jobs and other stuff each week!
The show airs Wednesdays from 12:30pm to 1pm on AM 1350, KSRO
He already has a few shows “in the can”. Listen to previous shows on the KSRO website.
My daughter is building a project for school that consists of (15) 6volt .250ma panels. She is wiring these in series-parallel as (5) strings of (3) to get 18V nominal at about 1.25A. The individual strings will have schottky blocking diodes before being paralleled and all fed into 5A MPPT controller/charger. My question is two-fold: 1) would bypass diodes be helpful (even remotely) across each 6V module? I have lots of 9A 45V Schottkys available so price is not a concern. But if one panel is bypassed, then the remaining 2 providing 12-14volts would be insufficient charging voltage and be way off from the other 4 strings of 18-21 volts. Or will it not help provide energy but only serve to protect any one cell from the other 2 dumping into it in a given string? 2) would minor voltage differentials present a problem between the strings if all are within a couple volts of eachother, between 18-21? Is there a way to better balance them or combine them to negate this effect using just one MPPT controller? Thanks!
Hi Shane. Sorry but I’m not sure. Keep asking around.