I mounted our new 140 watt polycrystalline solar panel and tracked its performance for four days in northern Lake Huron, Michigan. Fortunately, I experienced different weather conditions each day so there is some data to compare the 140 watt panel to the 130 watt monocrystalline panel. The panel was tilted at a 30 degree angle and rotated three times during the day; morning, noon and late afternoon. The panel was partially shaded by the back stay during the late morning. This seemed to degrade panel performance by about 1 amp. When pointed toward the sun during a clear sky period, the panel produced between 8 and 9.6 amps, considerably higher than its rated output. The controller recorded a max output of 10.6 amps. This is very impressive and shows the Class A silicone wafers are clearly worth the added cost over Class B wafers. Power consumption was from refrigerator/freezer, computer, lights (LEDs) and radio. The house battery bank was negative 28 amp hours after four days. Had the sunny day been the last day, the battery bank would have been fully charged. Below is the data:
Amp Hours Weather
Day 1 80 AH Sunny all day
Day 2 62 AH Hazy, partly cloudy all day
Day 3 31 AH Cloudy, overcast, rain until 5 PM
Day 4 56 AH Hazy, partly cloudy, no clear sky all day
The 140 watt polycrystalline panel performance is comparable to our 130 watt monocrystalline panel.
The panel performed above its rated output by 1-2 amps.
Performance during cloudy and hazy periods was very good.
The 140 watt panel appeared to have less sensitive to shading than the 130 watt panel.
Relative solar panel size: the 140 watt panel is smaller than the 130 watt panel by only 3 square inches.
The performance of our 130 watt solar panel is documented in an earlier blog entry below.
I will publish additional data as it becomes available.
Thomas Trimmer has been cruising with his Ericson 38 sailboat on the Great Lakes for over 20 years. He has pioneered the use of solar energy for wilderness cruising. He is continually designing and building equipment to simplify and enhance the cruising experience.