This year we tested our new 160 Watt SunPower cell solar panel with our integrated water heating system on a 6 week cruise in Northern Lake Huron at a latitude of about 46 degrees. We used an EP Tracer BN 20 amp MPPT Controller. The 160 watt panel provided plenty of power to meet our 70 amp hour per day requirements. The 160 watt panel was mounted using our CMP pole mounting system so I could tilt and rotate the panel to achieve optimum sun angle. I set the sun angle once and rotated the panel three times a day (morning, midday, evening) and figure I got about 30% more performance over a fixed horizontally mounted panel.
Operating statistics: Our power usage averaged approximately 70 amp hours or 850 watt hours in a 24 hour period. Our current draw was from a refrigerator/freezer running 24/7, our LED lights in the evening, cell phone chargers, laptop computer several hours a day and our radios and instruments during the day. Our windlass is only run when the engine is running so we don't include it in our power consumption calculation as the alternator quickly makes up for its power usage. We have a 75 amp Balmar alternator with a smart regulator. Our house bank consists of 3 flooded cell batteries giving us a total capacity of 330 amp hours. We started the engine to move anchorages about every three days. Results and findings: 1. Our battery bank was fully charged by 1 PM most sunny or mostly sunny days when at anchor. This is in contrast to 2 PM in last year using our 120 watt panel on a pole. 2. The EP Tracer BN MPPT controller with the remote display proved to be an outstanding piece of equipment. It was simple to program, easy to read, collected the appropriate data and was very efficient. It was exciting (I get excited about these things) to see 9+ amps being poured into the battery bank in the morning. It would be frustrating to see it only outputting and amp or two in the afternoon in full sun but then you realize it is doing its job. It fully charged the batteries in the morning and was in float mode topping off the battery bank in the afternoon. 3. Rotating the panel during the day, especially in the morning, significantly increased the power generation of the panel. 4. The data gathered confirmed that this panel configuration supplied all the power we needed and has excess capacity to catch up on battery charge from a string of cloudy days. 65. The panel was affected by shading as would be expected. Occasionally the panel was shaded by the back stay or the mast. While the shading was minimal, it degraded the performance by up to 40%. Data: At anchor Motor Sunny to Cloudy to Mostly Sunny Mostly Cloudy Average watt hrs per day 1,047 645 700 220 Average amp hours per day 55 40 60 40 Maximum watt output in 24 hours 1,210 770 1,210 770 Maximum amp hours in 24 hours 100 64 100 64 Observations: 1. The minimum watt hour output doesn't mean much because it is dependent on both the cloud cover and the state of charge of the bank as a result of alternator charging, 2. The maximum watt hours per day of 1,210 is not the maximum output capacity of the system in a 24 hour period because the batteries were charged by 1 PM so the controller shut down the charge from the panel. A higher drain on the house battery bank would have resulted in this number being higher. 3. Average amp hours per day is computed by dividing the watt hours by 12 volts. This is a ballpark calculation. 4. This configuration proved to have plenty of capacity for our cruising needs even without using an auxiliary flexible solar panel we store under a bunk. We did not use shore power to charge our battery bank for the entire summer. Solar Water Heater: We installed our new solar water heating system. It consists of a heat collector or heat exchanger mounted on the back of the solar panel, and a circulating pump. See our earlier blog for design considerations. The pump circulates water from the water heater through the heat exchanger on the panel. We used the same configuration on our 120 watt panel last year. Results: On sunny days at anchor we had warm water for showers and dish washing. The water temperature in our 6 gallon hot water tank would warm from 60 degrees to about 105 degrees in 2-31-2 hours on a sunny calm day. As expected, we confirmed that strong winds tend to cool the panel and reduce the heating efficiency as do clouds. Overall, the water heating system cools the surface of the panel by at least 20 degrees. This increases the efficiency of the panel since solar panel performance degrades as they are heated by the sun. Insulating the tubing running between the heat exchanger and the water heater significantly increased the efficiency of the system. In conclusion, the radiant energy water heating system works well on sunny days with both our larger and our standard sized panels. See our product section or read our earlier blog for details.
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We tested our new 150 watt polycrystalline solar panel on a 35 day cruise in the North Channel area of Northern Lake Huron. This panel was equipped with the prototype of our solar water heating system which will be addressed in another blog entry. The solar panel was mounted on our pole mounting system and was rotated toward the sun The boat equipment and cruising pattern was essentially the same as last year (See prior blog entries). We were powering a freezer/refrigeration system, instruments, laptop computer, radios, autopilot, windlass and LED lights. Data was gathered using the remote display on our EP 10 amp dual output solar controller. The solar panel performance met our expectations. Our house battery bank consists of three 120 amp hour flooded batteries.
Both battery banks were usually fully charged by 2 PM when at anchor and on mostly sunny days so we often had excess power. Data comparing the performance of the 150 watt solar panel with our 140 and 160 watt panels is presented below. Average amp hours per day produced under various conditions: 150 Watt poly 140 Watt, poly 160 Watt, mono 160 Watt, mono 2015 2012 2013 2014 Overall average output per day 49 amp hours 53 amp hours 48 amp hours 48 amp hours Sunny days 60 69 71 69 Mostly sunny days 56 50 50 56 Mostly cloudy days 36 35 37 39 Cloudy days 22 32 28 20 Avg. Output on days at anchor 60 62 61 51 Avg. Output when engine was used 42 43 44 45 Min amp hrs for a day 4 27 28 4 Max amp hrs for a day 84 74 77 76 Max amps output 11.8 amps 10.5 amps 11.5 amps 11.4 amps This data is intended to provide a general idea of what to expect from the solar panels under various conditions. The two primary variables are the amount of sunshine and the running of the engine (the alternator charges the batteries so the controller shuts off power from the panels). Because the panel was equipped with a water heat collector on the back, it may have run hotter on sunny days when the water circulation pump wasn't run thus degrading the performance by up to 10%.The average panel output on sunny days at anchor with no motoring was 67 amp hours. This was the second year we used the 160 Watt solar panel on a 35 day cruise in the North Channel area of Northern Lake Huron. The boat equipment and cruising pattern was essentially the same as last year (See prior blog entries). The solar panel performance was comparable to last year with a few minor exceptions. The data comparing the performance of the 160 Watt panel during 2013 and 2014 and the 140 Watt panel in 2012 is displayed below.
Average amp hours per day produced under various conditions: 140 Watt, poly 160 Watt, mono 160 Watt, mono 2012 2013 2014 Overall average output per day 53 amp hours 48 amp hours 48 amp hours Sunny days 69 71 69 Mostly sunny days 50 50 56 Mostly cloudy days 35 37 39 Cloudy days 32 28 20 Avg. Output on days at anchor 62 61 51 Avg. Output when engine was used 43 44 45 (We had more cloudy days at anchor this year) Min amp hrs for a day 27 28 4 Max amp hrs for a day 74 77 76 Max amps output 10.5 amps 11.5 amps 11.4 amps This data is intended to provide a general idea of what to expect from the marine solar panels under various conditions. The two primary variables are the amount of sunshine and the running of the engine (the alternator charges the batteries so the controller shuts the panels down). The test boat was running a freezer/refrigerator drawing 5 amps running 6 hours a day, LED lighting, laptop computer drawing 4 amps running 3 hours a day, radios drawing 3 amps running 8 hours a day, and instruments and autopilot when under sail and power. When at anchor on a sunny to mostly sunny day our batteries were at full charge by 2 PM so we usually had excess power. In an earlier blog entry dated 8/10/2011 I documented the performance of our 130 watt mono-crystalline solar panel on a 22 day cruise in the upper Great Lakes. In an August 2012 blog entry I documented the performance of our 140 watt poly-crystalline solar panel. This year I documented the performance of our 160 watt mono-crystalline solar panel on the same boat under similar conditions. The only variables were the weather and the running of the engine when moving from anchorage to anchorage (wind was on our nose quite often this summer). The number of days of each cruise varied so I an presenting average performance based on four weather conditions; sunny, mostly sunny, mostly cloudy and cloudy. Test conditions:
Test Results: Definition: amp hour – amps produced or consumed in one hour Average amp hours per day produced under various conditions: 130 Watt, mono 140 Watt, poly 160 Watt, mono Overall average output per day 54 amp hours 53 amp hours 48 amp hours Note: 160W had only 5 sunny days, 140W had 10 sunny days and 130W had 8 sunny days Sunny days 71 69 71 Mostly sunny days 51 50 50 Mostly cloudy days 46 35 37 Cloudy days 24 32 28 Avg. Output on days at anchor 62 62 61 Avg. Output when engine was used 35 43 44 (difference partially because 130W was often disconnected often when engine was used. Not so for 140W and 160W) Min amp hrs for a day 16 27 28 Max amps output 10.5 amps 10.5 amps 11.5 amps Interpreting the Results: Each solar panel performed about as expected. The average daily output was less for the 160 watt panel but it had half as many sunny days and comparable mostly sunny days. The 130 watt mono panel provided a slightly higher average output on sunny days and the 140 watt poly panel provided a higher average output on cloudy days. The max output of the 160 watt panel was an amp higher that the others. My sense was that the poly-crystalline panel was less sensitive to shading from the rigging but this is difficult to document. On sunny days, both solar panels often performed above their sticker rating of 130, 140 and 160 watts by as much as 50 watts (9.5 amps at 21 volts is 189 watts) . I believe this is due to the high quality of silicone crystals used. Observations: All three solar panels generally met our power needs for the duration of the cruises. We occasionally ran a small deficit of amp hours during an extended anchorage when cloudy but never needed to use the engine alternator to charge the battery banks except when motoring from place to place. On days when the engine was used we often had an excess of power generation from the 75 amp alternator and the solar panel. Choosing the right type of solar panel: Based on the performance data, each solar panel will perform adequately under most conditions. The 130 watt and 160 watt mono-crystalline solar panels are an excellent choice for boats in mostly sunny areas with little possibility of shading from the rigging. The 140 watt poly-crystalline solar panel is an excellent choice for areas with more partly cloudy and cloudy days and on boats where there is some shading from the rigging. |
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AuthorThomas 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. Archives
July 2024
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