1. Panels in a multi panel system with panels wired in parallel should have a diode in series with each panel, but many panels come with an incorporated diode and adding another one will just waste power. The manufacturer's documentation will say it there is a diode incorporated since that is an added feature.
2. There is no problem hooking up multiple panels to the same charge controller so long as you stay within maximum ratings. Multiple controllers should work fine, but at an added cost. Quality controllers are not particularly failure prone, but I get you desire for redundancy as a matter of principle. 3. I have had good experience with Morningstar controllers, and my choice was influenced by recommendations from several people. Whatever you purchase, get a decent one, and if it has at least a few LEDs to indicate the controller's state and the battery state of charge then you probably won't need a separate battery monitor. A battery volt meter and a current meter for observing charge rate, will be sufficient in my experience. I can't really see that a separate monitor would be of any use unless it can at least keep a running total of the ampere hours delivered to the battery. 4. MPPT controllers will squeeze a bit more current out of your panels but at an increased cost of purchase. Different panels have different efficiency ratings, and all else being equal, will cost more in proportion. 5. My experience with bimini mounted panels last winter is that on a sunny day at anchor you can expect the maximum mid-day charging rate to be about 1/2 the panel ratings, and the total ampere hours for the day to about 3 times the maximum amp rating total for the panels. (You never get the rated output of a panel unless it is pointing squarely at the sun.) To put it another way, with 2 100 watt panels rated at 7 amps each, we got around 7.5 amps at noon hour with both panels in parallel and at the latitude of Miami. This worked out to better than 45 ampere hours per day with the setup we had. Combined with a small wind mill, it was enough to keep the ice box refrigeration going without having to run the engine for a couple of weeks. Steve Thomas ----- Original Message ----- From: Josh Muckley via CnC-List To: C&C List Sent: Tuesday, October 14, 2014 5:43 AM 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
_______________________________________________ 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
