Josh: You've certainly given this a lot of thought. Don't overthink or overbuild it. KISS
If it were me, I'd go with two 100 watt panels back to a single $50 controller and keep the wiring as simple as possible. Keep in mind you're talking about a system that will deliver about 60 ah per day (12v). Frankly I wouldn't even worry about a load assuming you're wiring it directly to a battery bank of any size and not through a switch. You may also want to look at panels from RV stores which are usually identical but lack the boat related price. Check model numbers carefully if you go that route. Keep in mind the weight going onto the Bimini as 4 50 watt panels will nearly double the weight of 2 100w panels. You'll also double the mounting hardware, etc. Just my 2 cents. John Sent from my iPad > On Oct 14, 2014, at 5:43 AM, Josh Muckley via CnC-List > <cnc-list@cnc-list.com> wrote: > > 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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