You might be well advised to look at Sailboat Owners forum, where this has been discussed multiple times (e.g. here: http://forums.catalina.sailboatowners.com/showthread.php?p=1149325&highlight=solar%20panel). Also, a good read here: http://www.pbase.com/mainecruising/solar_panel.
There are various reports on using the cheap panels vs. the high quality expensive. Apparently, the expensive ones are most often produced in the same factory, on the same production line; however, they are thoroughly tested, so that all cells are working properly and produce equal amounts of energy. The cheap ones are the ones that did not make it through that QA. Don’t skimp on controller(s). There are well documented reports showing that some can deliver substantially more energy (15% or even 20% more), which is especially important if you are using the solar panels to top up your batteries. >From what I read, GenaSun controllers have the best opinion (price per >performance). Morning Star controllers (supposedly) are also quite good (this >is what I have). Some controllers offer dual battery connection (with 50-50 or 90-10 split). If I were doing it again, I would install a simple controller (going to the house side) and an Echo Charger to charge the starting (spare) battery, as needed. I don’t think you need a “dump load”, if you connect it directly to the batteries. If you use multiple controllers, you will have some fun in controlling them, as they would see the wrong voltage on the battery (they would see the combined voltage of all controllers; rather than the battery itself). However, I don’t think you need any diodes, as they all have this protection built in (so the battery cannot feed the panel). have fun Marek s/v “Legato” in Ottawa From: Josh Muckley via CnC-List Sent: Tuesday, October 14, 2014 5:43 AM To: C&C List Subject: Stus-List Solar panels and charge controllers Hey folks, I'm looking to add solar panels to my boat. I have a new hard top dodger that will be a great place to mount some flexible panels. I realize that attention will have to be given to the boom so that it's shadow it minimized. I've given consideration to the fact that some shadow is likely inevitable. My understanding is that one large solar panel can have a substantial drop in it's output or be completely disabled if only a relatively small shadow is cast. As such I am planning for 4 smaller 50w panels instead of 2 100w panels. The idea being that a small shadow will only disable 1 or 2 of the panels at a time. This design also adds reliability such that a mechanical or electrical failure of a single panel doesn't disable the entire system. Additionally, a smaller panel is easier to replace and cost less. To ensure reliability I was also planning to NOT creat an array of series and parallel panels going to one controller but rather each panel to its own controller. I believe the current recommendation is to use MPPT over PWM? There is a wide range of prices for panels and controllers but I'm having a hard time determining which ones are a good value. I know you get what you pay for but over paying is silly. At the boat show, 50w, semi-flexible, >20% efficient, monocrystalline panels were going for as much as $500! I've seen charge controllers as high as $250. I know there are a few ebay haters here but the comparable panels I found were $125 and 20A MPPT controllers for $11 with free shipping. Is there something I'm missing? Besides disparaging comments about ebay or about me being cheap, does anyone have any insights about the design or component selection. I was originally pursuing a multi-channel controller but it seems no one makes them. When using multiple (4) controllers do they need to be diode separated from the battery? What about the dump load? I plan to use a single 200w resistive heater. Would it need to be diode separated from each controller? Thanks, Josh Muckley S/V Sea Hawk 1989 C&C 37+ Solomons, MD -------------------------------------------------------------------------------- _______________________________________________ This List is provided by the C&C Photo Album Email address: CnC-List@cnc-list.com To change your list preferences, including unsubscribing -- go bottom of page at: http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com
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