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. This year I documented the performance of our 140 watt poly-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). Also this panel performance was documented over a longer period of 34 days. Test conditions:
- The boat has two deep cycle wet cell battery banks; 315 amp hours and 105 amp hours.
- The boat has holding plate refrigeration which draws 5 amps. The weather was very warm so the frig compressor ran more than usual; 8+ hours a day. The lap top computer was used for navigation and draws 3 amps. All lights are LEDs.
- When motoring, the panel was usually connected to the controller.
- The dual bank controller shuts off power from the panel when the batteries are fully charged. i.e. After 3 or more hours of motoring.
- The Remote Display of the dual bank controller was used to collect all the data.
- Our mode of cruising was to anchor for 2-4 days at a time and move on to another anchorage. We did not dock and use shore power during the cruise.
- The tilt angle of the panel was rarely changed; usually about 45 degrees. The panel was rotated for optimum sun angle on an average of 3 times per day.
Definition: amp hour – amps produced or consumed in one hourAverage amp hours per day
produced under various conditions: 130 Watt, mono 140 Watt, poly
Overall average output per day 54 amp hours 53 amp hours
Sunny days 71 69
Mostly sunny days 51 50
Mostly cloudy days 46 35
Cloudy days 24 32
Output on days at anchor 62 62
Output when engine was used 35 43 (difference because 130W was disconnected often
when engine was used. Not so this year for 140W)
Min amp hrs for a day 16 27
Max amps output 10.5 amps 10.5 ampsInterpreting the Results
Both solar panels performed as expected. Their average daily output was about equal. 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. 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 and 140 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:
Both the 130 watt solar panel and the 140 watt solar panel 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 used 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, both solar panels will perform adequately under most conditions. The 130 watt mono-crystalline solar panel is 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.
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.
We haven't been just sitting around waiting to the water to soften up here in the Midwest. We've been working on enhancing our products and finding the latest and greatest technology.
Our 90 watt solar panel had been such a popular high performer that we went back to our supplier to see if they could provide us with a higher wattage panel for our top-of-pole mounting system. We specified a solar panel that was Class A-9 quality polycrystalline with an efficiency of 16.5% efficiency or higher, sealed and robust for the rigors of marine use, a nearly square shape for our top-of-pole application, and at a cost our customers could afford. They met our request and came up with a 140 watt polycrystalline high performance panel that measures roughly 39 X 39.5 inches and uses the same design and construction technology as our 90 watt panel. We have them on order with an expected delivery date of early May.
We anticipate that the 140 watt panel will perform about as well as our popular 130 watt monocrystalline panel in full sun and outperform our 130 on a cloudy day or when partially shaded. This will make the panel ideal for northern climates where those sunny days just don't happen every day. We plan on publishing a complete analysis by mid to late June.
Also stay tuned for our introduction of several new LED lights.
Only recently has LED technology advanced to the point of offering brightness and reliability that meets or exceeds that of traditional bulbs and at an affordable price. Cruising mariners know that cabin lighting can consume a significant amount of electrical energy. Fortunately, cabin lighting is simple and relatively inexpensive to modify to achieve energy savings; simply change the bulb.
Advantages of LED lamps include:
Some information to help you select the proper LED lamps:
- Low power consumption (10% of comparable halogen and incandescent bulbs).
- Low heat generation with high system efficiency.
- High reliability and long operating life to minimize maintenance (our built in voltage regulator is key).
- LED’s contain NO polluting material (mercury) and facilitates easy lamp recycling.
- LED lamps can be configured to be as bright or brighter than halogen and incandescent lamps.
- The light from LED lamps does not distort colors.
Our customers interested in reducing their power consumption frequently ask us about LED lighting. We at Custom Marine Products have extensively researched LED lighting technology and decided to offer the highest quality replacement LED lamps from the best manufacturers we could find. Our marine grade LED replacement lamps are designed to replace both halogen and incandescent bulbs commonly found on boats and RV's. All of our replacement LED lamps are equipped with a built in voltage controller (Buck Power Converter) to compensate for the variable voltage that occurs in the marine environment being powered by storage batteries. This circuitry ensures maximum brightness and maximum operating life. Now our customers can equip their boats and RV's with a lighting system that will use only 10% of the power of halogen and incandescent bulbs and provide equivalent or brighter light.
- Color - LED replacement lamps are available in various colors including red, cool white and warm white. Cool white lamps are very white or blueish in color and provide the maximum light. Warm white lamps have a slight yellow tint much like incandescent and halogen bulbs. They are about 5-7% less bright and more closely match traditional lighting.
- Brightness - The brightness of LED lamps is measured in lumens. The greater the lumens, the brighter the lamp.
- Reliability - The nature of boat electrical systems is to have voltage spikes and variable voltage depending on the charge of the batteries and the power generated by charging systems such as alternators, shore chargers and solar panels. This variation in voltage is often the key factor in LED lamps failing. Thus, the necessity for a built in voltage regulator called a DC/DC constant-current converter also called a Buck Power Converter. All of our LED lamps have one. See Idiots Guide to LED's by Jeff Field at http://lib.store.yahoo.net/lib/yhst-54258538930337/IdiotsGuide.pdf for more information.
At other places on this blog and on our web site we talk about how to determine the size of solar panel (how many watts) you will need to meet you power consumption requirements. Once you know your panel size requirement there are some things to consider in selecting a solar panel.
Panel Type - There are many articles written on the two types of solar panels; monocrystalline and polycrystalline. Monocrystalline panels are made up of single crystal silicon wafers. Polycrystalline panels are made up of silicon that has a multiple crystalline structure. There are pros and cons to each type of panel. Monocrystalline panels have a higher output per square inch in direct sun but are very sensitive to shading and output will degrade faster on cloudy days. Monocrystalline panels are not as sensitive to being shaded and output will not degrade as much on cloudy days. At CMP we offer both a polycrystalline and a monocrystalline panel.
Panel Crystal Quality - Because we have a confined space on our boats, we need to have the maximum output per square inch from our solar panels. The quality of the silicon crystals used to make the panel is a key factor in determining the panel output. Crystals are passed under a fixed light and graded as to their output (1-10). Grades are grouped into classes. Class A crystals are grades 8-10, Class B crystals are grades 4-7 and so on. Crystal quality follows a bell curve; there are many more Class B crystals than Class A. We at CMP specify only the best Class A crystals for use in our panels. Less expensive Class B and C panels are often used on land based solar farms where space is not an issue.
Panel Shape - The largest market for solar panels is commercial applications where many many panels are mounted on a roof or in a field. These panels are usually rectangular in shape often twice as long as wide. This shape is often not ideal for marine application. Often a more square shape is preferable, especially for pole mounting.
Choosing the right panel for your needs will require study and/or discussion with panel experts.
The following is the result of testing the CMP130 watt monocrystalline solar panel with the top-of-pole mount and dual output controller cruising for 3 weeks in the North Channel of northern Lake Huron. The panel mounting system is shown on our Gallery of Installations; the Ericson 38. (Well, somebody has to do it. :-) ) Test conditions:
Test results – raw data for solar panel output:
- The boat has two deep cycle wet cell battery banks; 240 amp hours and 120 amp hours.
- The boat has holding plate refrigeration which draws 5 amps. The weather was very warm so the frig compressor ran more than usual; 8+ hours a day. The lap top computer was used for navigation and draws 5 amps. Most lights are LEDs.
- When motoring, the panel was usually disconnected from the controller so the smart regulator would get an accurate reading of the battery bank condition thus achieving max output from the alternator.
- The dual bank controller shuts off power from the panel when the batteries are fully charged. i.e. After 4 or more hours of motoring.
- The Remote Display of the dual bank controller was used to collect all the data.
- Our mode of cruising was to anchor for 2-4 days at a time and move on to another anchorage. We did not dock and use shore power during the three week cruise.
- The tilt angle of the panel was rarely changed; usually about 45 degrees. The panel was rotated for optimum sun angle about 4 times per day.
Date Amp Conditions of the day Hours
7-7 46 At dock, shore power on
7-8 39 Motored 4 hours, partly cloudy
7-9 17 Motored all day, cloudy tried solenoid
7-10 26 Cloudy, motored 1 hour, sun 5-6 hours
7-11 55 Mostly sunny, travel day – under sail
7-12 64 Mostly sunny, at anchor
7-13 79 Mostly sunny, at anchor, reset meter when rewired batteries
7-14 70 Mostly sunny, at anchor, panel not turned for part of the day
7-15 49 Cloudy morning, sunny afternoon, motored for 2 hours with solenoid on
7-16 51 Mostly sunny, motored 2 hours with solenoid on, topped off batteries
7-17 34 Mostly cloudy, at anchor all day
7-18 47 Mostly cloudy, motored 2 hours
7-19 20 Hazy, cloudy, motored 2 hours
7-20 71 Sunny, at anchor
7-21 80 Sunny, at anchor
7-22 67 Mostly sunny, ran engine 1.5 hrs, topped off batteries
7-23 39 Mostly cloudy, at anchor
7-24 73 Mostly sunny, at anchor
7-25 68 Mostly sunny, at anchor
7-26 16 Hazy, cloudy, motored 4 hours, topped off batteries
7-27 26 Cloudy, hazy, motored 9 hours, batteries charged
7-28 42 Mostly sunny, motored 2 hours with panel connected, batteries charged
Definition: amp hour – amps produced or consumed in one hour
Average amp hours per day produced under various conditions:
Overall (22 days) 54 amp hours
Sunny days at anchor 71
Cloudy days at anchor 37
All days at anchor 62
Days engine was used 35Max amp hrs for a day 80
Min amp hrs for a day 16
Max amps output 10.5 amps
The 130 watt panel generally met our power needs for the duration of the cruise. We occasionally ran a small deficit of amp hours during an extended anchorage but never used 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 130 watt solar panel.
The solar panel is very sensitive to cloudy days and to shadows. The panel output on sunny days exceeded it rating. This is the nature of mono-crystalline solar panels.
Several fellow mariners have reported their engine Tachs sometimes give sporadic readings with the needle bouncing around. I recently had a similar experience on my boat and did some research. Most high output alternators with smart regulators and many solar panel controllers charge batteries using a technology called Pulse Width Modulation (PWM). The Tach uses PWM to determine the alternator (and thus the engine) RPM. The two PWM sources may, at times, create an interference. Thus the sporadic readings on the Tach.
The solution to this is disconnect the solar panel when the alternator is running so the controller doesn't function. This can be easily done by putting a switch in the positive wire leading from the solar panel to the controller. Alternatively, you could put in relay (closed when no powered) on this wire and wire it so the relay is open when the engine is running and closed when it is not.
There is another very good reason to put a switch in the panel to controller wire. The smart regulator reads the battery charge condition and sets the output of the alternator accordingly. If the solar panel is producing power, the regulator will see the net of the battery charge plus the panel output and thus may prematurely put the alternator in float mode. this will result in getting limited performance out of that big expensive alternator.
The Kyocera KC85T is a solar panel we have recommended for pole mounting on boats with moderate power requirements. It has been very popular with our customers. Unfortunately, Kyocera no longer manufacturers this panel. To serve our customers, we are having a similar panel manufactured to our specification. This panel is the same dimensions as the KC85T, is rated at 90 watts, and is a polycrystalline Class A marine grade solar panel. This panel has a 10 year manufacturer warranty and a 10 year warranty from CMP. Out tests indicate that this panel is an excellent performer. It is now in stock and can be ordered through our web site with or without our custom top-of-pole mounting system.I recently mounted the 90 watt panel on my boat in the Great Lakes to see how it compared to ym KC85T. The results were impressive. The 90 watt panel produced 5.5 to 6 watts consistently on sunny days (rare this Spring) and achieved a max output of 7.3 amps. It will easily produce 35 amp hours a day.
We also now offer a 130 watt solar panel which has the same dimensions as our 120 watt panel. It is ideal for pole mounting because it only weighs 24 pounds and is shorter and wider than standard panels of similar power.If you have a need for smaller panels on your boat, check out Atom Voyages. James offers a top-of-pole mounting system that is ideal for panels in the 50 to 65 watt range.
The amount of power needed while cruising depends on many factors including the energy used by appliances and lighting, the output of the engine alternator, the climate and the length of time away from shore power. These and other factors will determine the amount of solar power and thus size of the solar panel(s) you may need. Working with Ed Foster of foster-wills.com, we have developed a worksheet to assist you in inventorying your on board power generation and consumption and estimating you solar power requirement. Print out our Solar Power Calculation Worksheet
and use it as a guide to figuring out your power generation requirement. From this you can get an idea of what your solar panel options might be. Hope it helps!
We are often asked about the impact of wind resistance on solar panels mounted on a pole when the boat is under sail or when it is blowing a “hooley” out there in heavy seas. This is a valid concern. Anytime you put something in the way of the wind on a boat there are bound to be consequences.
It is important to note that none of our customers to date have reported a problem with wind resistance nor have we had a problem on our test boats.
Fortunately, an adjustable pole mounted solar panel offers numerous options to address wind resistance. Some of our customers have reported that they tilt their panel to a horizontal position in a blow to minimize wind resistance. Other customers have replaced the single nut and bolt that attaches the panel to the pole with a locking pin or lynch pin. In a blow, they simply pull the pin, unplug the panel and stow it down below. Other customers just leave the panel alone and don’t worry about it.
The panel is usually tilted at a 30 to 45 degree angle to achieve optimum sun angle. This alone reduces wind resistance by over 50% relative to a panel in a vertical position perpendicular to the wind (not sure why a panel would ever be in a vertical position however). Also, it is important to consider that the boat is moving smoothly with the waves thus enabling a relatively even airflow over the panel. In addition, the panel can be rotated so achieve some potentially beneficial results. With the top of the panel tilted into the wind, the unit will tend to put a downward force on the stern. With the panel bottom into the wind, it will tend to put a lifting force on the stern.
What is the weak point in the system in a heavy wind? Looking at the system as a unit, it is apparent that the pole, the tilt mechanism and the braces attaching the panel to the tilt mechanism are plenty strong. The brackets attaching the pole to the stern rail are plenty strong. Our tests have proven this to be a fact. The only remaining point of potential failure then is the stern rails. We have seen boats with very strong well anchored stern rails and boats with rather dubious stern rail anchoring systems. Each boat owner must assess the strength of the stern rails and determine their ability to support the stresses of a pole mounted solar system. It could be that lateral braces connecting the pole to the deck or to the bimini frame are necessary.
The size of the panel is directly proportional to the amount of potential wind resistance. We recommend mounting a panel no larger than our 120-130 watt panel which measures approximately 49 X 32 inches on a boat with strong well designed stern rails. The Kyocera 85 watt panel measuring approximately 40 X 26 inches is ideal for our smaller panel system. See other blog entries for an analysis of the performance of this panel.