Help with picking out a solar setup for my boat

Whoa !! Don't buy anything yet.

Boats have 2 major problems:

* Shadows from antennas, masts, stays, everything.

* Varied Sun angle. Do not mix port solar array with starboard array, needs 2 controllers, one for each array or shaded array will disable illuminated array.

* Corrosive water (salt water sometimes)

Sailboat (Yanmar 7.5hp engine that's likely) or Powerboat ? Live aboard or weekender ?

What are your trying to do - reduce engine run time ? Extend battery life ? Avoid running engine just to charge batteries ? You will NOT be saving any money adding solar.

Tell us more of what you need to accomplish, and we'll try to help with the best solution, which may or may not be solar.

It's a Cal 3-27 sailboat, I'll be using it as a liveaboard while I travel around the coastal US & Caribbean. I'll be living aboard for quite some time, very likely many years as I want to take it slow and enjoy my life while I do it. It's not much of an offshore cruiser so my sailing will be done in almost exclusively in fair weather and I like to focus on longevity of the other gear so pushing the boat won't happen, I'll be taking it slow and steady so I doubt salt water will be too much of a problem.

I need to be able to power my laptop and on occasions a low wattage gaming pc I built and any other general items that need power, vhf, sound system, sink pump, anchor light(LED), interior lights (all LED's). I'd like to be self sufficient as much as possible and won't have a car, I'll be staying at each anchorage from a few weeks to a few months depending on how much I like it and just traveling with the weather. Using diesel fuel seems like a bad choice to me especially considering engine maintenance so I'd like to limit the use of that as much as possible for anything other than motoring in and out of a channel. I'd like to avoid having 2 charge controllers as they are quite expensive. The only reason I said 2 to port and 2 to starboard was to even things out, since the array will only weigh like 90lbs or so total I could put them all on one side or probably even near the transom which will also be out of the way of most of the stays. I know even a small shadow can reduce the power generation of the panels significantly so I can mess with it until I get a nice spot.

If they is anything else I can answer so you can help me better please let me know.

I would look into wind for a boat. 2 good turbines will keep your batteries charged up better than solar I would think, at least that is the route people go here in Hawaii.

For use while sailing, a drag turbine is worth looking into for the same reason. Not much good when at anchor though, unless the tides are outrageous.

Besides the previously mentioned concern for shadows you really should think about a pure sine wave inverter for those electronics.

You also did not mention the Ah rating of those 12volt batteries. Knowing that will help determine what your daily watt hour use can be as well as how many panel watts you will need to recharge what you use every day.

And my final comment would be why go with solar when you will be staying in port most of the time? Does it cost that much to be connected to land line power?

Depends, among other things, on whether you are docked or just moored.

Ahh. Good point. He may just sit out in the harbor with no land line connections.

Thanks sun eagle, I was actually just looking stuff up about the inverters right before you posted it and realized that a pure sine wave would be better for technology onboard I was thinking about this one http://www.joyfay.com/800w-pure-sine...FeJF7AodzHEAlQ

I won't actually be staying in port (docking or mooring), I'll be at anchor away from any marina ideally all of the time so connecting to shore power can't really happen. I won't be sailing too much just a means for me to get from one anchorage to another and an occasional trip into the ocean to fish/dump holding tanks and just enjoy a good sail on a nice day.

I'm not sure of the AH on the batteries but they are Group 27, I haven't been on the boat too much yet as I just recently bought it and it's docked a good deal away from me and I don't have a car so I have to rely on friends, I would assume the batteries are about 90 AH each though. I know this is a little lower than I would want but I was just going to use them until they die or close enough and then upgrade to 4-6 of the same, that way they will all have the same amount of life on them. My laptop runs around 65W maximum and my gaming pc is about 200W maximum but only the laptop will see regular use and likely won't be running at max all that time and I can stop using it if necessary for long periods of bad weather with no sun. I know I never want to drop the batteries below 50% and ideally never below 75% but I also don't want to keep them topped up too long 95%+ constantly either so with this amount of battery power I'll probably be hanging out around 65-80 quite often and then tone down my usage from in relation to how far it drops. I've done quite a bit of research on all this stuff already and am kind of in a time crunch, I really just need help with wiring/connecting pieces to buy and if anyone has any ideas on cheaper products or knows some good websites that I might have missed. I'm sort of learning all the wiring/connect stuff on my own already though but still got some to look up and it's nice to have someone to double check things in case I miss something.

I've thought about wind turbines and might add a few eventually because the idea of 24/7 power generation does appeal to me but, the negatives for me are occasionally depending on what you get they can be noisy but they say you get used to the hum, and if I have a period of higher power consumption with solar panels if my batteries are already topped off I know I can spare it if the sun is still out with wind I don't know what will be coming and can only hope so I would have to drain the batteries a little and hope to replenish it later instead of right off. Also most ideal anchorage areas will have good wind protect which will lessen the amount of power I can get. So I'd like to stick with solar for now.

My concern about the size of the battery is that first it would be too small for your needs.

And second I wasn't sure if those 4 x 120 watt panels you wanted to buy would be to much or too little to properly charge the batteries.

A solar battery system needs to be balanced. Each part can't be too big or too small or something will fail which is most likely the batteries.

And those batteries should really never be discharged below 30% or their life is cut in half.

Before you purchase anything it would be better to understand what your daily watt hour load is and then size your batteries to meet your needs.

Yes I'm aware of the implication of dropping the batteries too low and will avoid that. Realistically my power usage can be pretty much whatever I need it to be, I have no electronics other than an LED anchor light at night that I can't just turn off and not use until I have more power. 24V times 90 amps = 2160 watts and never let them go below lets say 50% leaves me with 1080 watts of power, I'm sure there will be conversion losses somewhere so lets just knock off 20% for the hell of it which leaves me with 864 watts of power for the day or days if bad weather is around the corner. Laptop will not be processing intensive and will be the only primary thing I use often that consumes electricity, max is 65W but not at full capacity lets say about 30W per hour. Now lets say I use it for about 8 hours a day. That's 240 watts combined with other electronics shouldn't be more than 300W a day. That's almost 3 days with no power generation whatsoever before I drop into the danger zone and like I said I can tone down the usage and go without if necessary if it's constant bad weather.

480W of solar power with an MPPT charger should be more than enough to recharge the batteries and will allow me to use my gaming pc of around 200W during the day and still recharge the batteries.

As I said I'm only using these batteries until they are no longer in proper working condition at which time I'll be getting a larger battery bank of somewhere from 4-6 batteries probably 24V around 270A-300A and when I do that I may or may not install a small dc marine refrigerator of about 2 cubic feet capacity probably an isotherm 12V @ 2.5A but that's in the future and I'm looking to plan ahead a bit.

I'd be curious to see how you mount 480 watts worth of panels on a 27 foot boat. We got 320 watts on our 37 foot boat and on an ocean cruiser there is no room for any more. Ours are mounted on the arch and we broke one of them once when we got knocked down in a storm. And they don't produce anywhere close to ideal amounts of watt-hours because of the fact that they're never oriented right for the sun position.

So basically, I dunno about all your plans here. If you're going to be living aboard this boat the engine and alternator is your primary source of power. Solar is supplemental, not primary, because on a sailboat it don't work all that well.

I assume that you will be swinging on the hook in the harbor though on a mooring ball at the minimum? There's only a couple places we've been where you'd want to try to get your anchors to hold outside the harbor. And even then those places are touch and go. We got woke up by the anchor alarm off San Andres and found the wind and seas had picked up during the night and we were dragging anchor toward the rocks. So for long term liveaboard getting a transient slip inside the safety of the harbor is usually highly recommended. If you sail the Caribbean with a 27 foot boat and swing on mooring balls or simply drop anchor in the harbor you'll never get any sleep. Those harbors are crowded and every boat around you has generator going with air-conditioning.

I guess Mike already mentioned this, but you'll want your solar panels wired parallel. Some people put a separate controller on each solar panel on sailing yachts. We don't - we just got one controller for our two solar panels.

Also keep in mind when mounting your panels that you're talking about mounting them near the cockpit area. How do you plan on sailing the boat? I don't think there's enough room for one solar panel from the aft rail to the jib sheet winches on a Cal 27. At least not 120 watt panels anyway.

Not sure exactly where I will mount them yet. I've got a few places I was considering that would work, but like any cruiser without a giant arch to put them on, they'll just be off the side of the lifelines, propped up and easily removable for when I sail to a new area.

I know the amount coming out of them won't be what they're rated for I was actually expecting about half that from what I've read numerous places, which is still more than enough for me.

Activecaptain is a great site for looking up anchorages on the interactive cruising guide, lots of user reviews, there are many protected areas all over the place that are great for anchoring. I have a very large anchor for my boat size and it would take some serious wind and current to knock it loose and in even a roughly protected anchorage that's just not going to happen. I do however prefer to be alone as much as possible so I'll be travelling off the beaten path as much as possible but still expect to run into quite a few heavily populated anchorages.... I'll make it work.

No one ever seems to get that I'm not interested in a standard approach that mots people use, if I was I would waste my life working and then when I'm 67 retire and die all the while dreaming about doing something I've always wanted to do but will likely never get the chance to. I'm making quite a few luxury sacrifices most people couldn't imagine doing without and every step of the way I've been criticized about it. I don't know what makes people think I want their life because if I follow their advice that's all I'm going to get. I came here asking about connections and wire gauges and if anyone had any better ideas for the setup price-wise or knew some websites that were good. What I got were question, question and more questions and when I finally answered those questions all I got were criticisms. People telling me to get wind turbines, water turbines, people telling me to stay in a transient slip every night and use shore power, people telling me to use a 7.5 hp engine to generate power, next you'll tell me to just buy a generator. If I'm doing that, why sail at all why not get motor yacht. The amount of time and maintenance/parts that goes into an engine will surpass the cost of solar panels within a year. I've done the math! You know what else I've done, my own research because you all haven't helped a bit. Which is what I usually do from the start because every time I ever try talking to someone all I get useless rhetoric and criticism. I say don't worry about the battery bank I know it's too small I don't care how long it lasts I'm going to use it until it dies and the replace it and what does the next person say.... Hey dude, you're battery bank is too small! I don't know if you're all not reading or just so set in your ways that anything else is blasphemy.

But hey, if you want to criticize me some more instead of opening your mind and being accepting and help then feel free.

Things to also criticize me on:
I'll be using a sit-on-top kayak as a dinghy.
I'll be using that same kayak as an emergency life raft.
I won't have a job! I'm not contributing? Geez I must be a filthy lazy hippie for enjoying my life!
I don't have a windlass. Unheard of I KNOW, I'll probably crash into some rocks or other boats trying to get my anchor up! I'm just a danger to everyone at this point, lets hope I'm never near you right!?!?!?!

Lock & delete the thread, ban my account, it makes little difference at this point I won't be coming back I had to do the research on my own anyways. Better this way, don't know why I even bothered, what did I expect.... help?

Sounds like a plan to me. I don't know why the attitude all of a sudden. But if you don't like the advice and opinions of people that have already been there, done that then you should not have asked in the first place. Wire gauge is minor compared to the other problems you have already invented.

And yes - if you come into a harbor and see a yacht bearing the name "Kristin Kaye" - make sure you don't anchor anywhere close to it. I've already had the (dis)pleasure of meeting a couple of those sailors that had them anchors "that hold no matter what" and ending up with my anchor rode tangled in their prop.