Comparing Our New 160 Watt Solar Panel with Our 130 and 140 Watt Panels

Solar Panel Performance Comparison Across 22-Day Great Lakes Cruises

In previous entries, I documented our solar panel performance on Great Lakes cruises: a 130-watt mono-crystalline panel in August 2011, and a 140-watt poly-crystalline panel in August 2012. This year, I tested a 160-watt mono-crystalline panel under similar conditions. The main variables affecting output were weather and engine usage, as we often motored into headwinds. Each panel’s performance is averaged across four weather conditions: sunny, mostly sunny, mostly cloudy, and cloudy.

Test Setup

  • Battery banks: 315 Ah and 105 Ah deep-cycle wet cells
  • Refrigeration: 5 amps, ~6+ hours daily due to cooler weather
  • Navigation: Laptop drawing 3 amps
  • Lighting: LED throughout
  • Panel management: Typically connected to the controller while motoring
  • Controller: Dual battery bank solar controller, which stops charging when batteries reach full charge
  • Tilt and rotation: Panel angle set to ~45 degrees, rotated ~3 times daily for optimal sun exposure
  • Anchoring routine: We anchored for 2–4 days at a time and did not use shore power

Results Summary (Average Amp Hours Produced Per Day)

Condition 130W Mono 140W Poly 160W Mono
Overall average 54 Ah 53 Ah 48 Ah
Sunny days 71 Ah 69 Ah 71 Ah
Mostly sunny 51 Ah 50 Ah 50 Ah
Mostly cloudy 46 Ah 35 Ah 37 Ah
Cloudy 24 Ah 32 Ah 28 Ah
At anchor 62 Ah 62 Ah 61 Ah
Engine in use 35 Ah 43 Ah 44 Ah
Min day 16 Ah 27 Ah 28 Ah
Max output (amps) 10.5 A 10.5 A 11.5 A

Note: Fewer sunny days impacted the 160W panel’s overall output.

Analysis

All panels met our power needs, with occasional slight deficits on extended cloudy days at anchor. The 160W panel’s higher maximum output (up to 11.5 amps) and overall efficiency align with its rating, though performance was tempered by fewer sunny days. Interestingly, the poly-crystalline panel was less affected by shading, making it advantageous in partly cloudy or shaded conditions.

Recommendations

  • Mono-crystalline (130W and 160W): Ideal for sunny areas with minimal shading.
  • Poly-crystalline (140W): Better suited for partly cloudy or shaded environments.

Overall, each panel type can meet power needs under varying conditions, but selection should account for expected weather and shading.

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