Dixie Dime's original solar wiring consisted of two strings of nine 105-watt Pannels each wired in series resulting in well over 200 volts per string but low current. Though the panels totaled 1890 watts the max output we ever saw was just under 1400 watts when the sun was directly overhead. We had hope to install 2000 watts of panels on her originally, but sadly commercially available solar panels don't always efficiently cover all the real estate available on the cabin top with hatches and such. These panels were feed into a pair of Victron 250-85 Smart Solar controllers with one for the forward panels and one for the aft. We discovered that the shading of the forward array caused by the heat pump, radar dome and small mast forward were not only causing a drop in the strings output but also causing hot spots on some of the panels. In fact, it caused the buss to burn through the panel and even damage the painted surface below but strangely the panel still made power. Evidently the unshaded panels in the string were pushing enough current to cause a problem in the shaded ones. This buss burning didn't result in the circuit breaker kicking on that string.
The decision was made to modify the wiring and upgrade the forward four panels that were prone to shading and add an additional Victron controller. The aft seven panels per side were wired in series and attached to their own Smart Solat 250-85 controller. These two controllers were originally oversized for redundancy but have plenty of reserve capacity and either one could handle all 14 panels. The slight crown of the cabin top makes it more efficient to have two controllers to maximize the MPPT tracking. To recap, in the new configuration the port side panels except for the front two will be attached to one controller and the starboard side minis the forward two will be connected to another controller. The front four panels, two per side were replaced with shade tolerant type N panels. These panels have 27 diodes each and were wired in 2P2S configuration so hopeful the current or voltage will not be high enough to damage them when shaded. These new type N panels were connected through new wiring to a separate Victron Smart Solar 150/35 bring the total number of solar controllers on Dixie Dime to three.
So far with limited testing we are maxing out at about the same wattage but total yield per day is up due to higher efficiency in early morning late afternoon. The stated capacity of the installed panels actually dropped by 20 watts with the 100s replacing the 105s. I believe the new setup will allow another 500-600 watts per day to be harvested as well as stop the hot spot and burn panels.
