Marine applications

System · March 2008

I'm contemplating installing a wind/solar charging system on a sailboat. I have room for a couple of 200 plus watt panels and an air x wind charger. I'm thinking MPPT for a controller, probably that outback 60.

So my questions are as follows:

- What name brand or model of panel is going to hold up best in the marine environment?

- How will the wind generator (which is internally regulated) interact with the solar charger?

- What effect will happen when adding another charging source. Other possible sources would be..

-- Onboard 100 amp alternator on the diesel engine while motoring.
-- Generator charging through the Freedom inverter/charger.

Thanks for helping a newbie.

George

Solar Guppy · March 2008

Re: Marine applications

Sailboats are tough, with the constant varable shading, Mppt is close to useless in this application, and for this wattage, an MX60 uses more power than it can havest via the mppt feature ( it has a high idle draw and is intended for large, not small arrays

Best thing you can do is just use a pwm controller and wire all the solar panels parrallel. No tracking to get messed up, and all available energy goes into the batterys ... something like a Xantrex C40 or Morningstar Tristar would be my choice.

niel · March 2008

Re: Marine applications

me thinks we have another racer. even if not the pvs could back you up if stranded out in the waters somewhere.
for durability the thin films like unisolar are up there, but if no physical stresses to the pvs are possible then any will work. i think the airx is a waste at this point. multiple charging sources would not be a problem to the pvs for if the battery is charged then it will not feed a charge to it.
the way around the shading is to parallel pvs on differing sides of the boat as at least one of them will output power.

System2 · March 2008

Re: Marine applications

I am also interested in any reply or suggestions one can give on this question. My interest comes from a houseboat standpoint, with easily 300sqft of deck area available on a 38ft houseboat, why not pull from the grid forever ? It would seem everything is already in place to make the conversion including a gen set and inverter for those less than optimal days or am i missing something ?

Thanks

BB. · March 2008

Re: Marine applications

First, how much electricity do you need... Winter? Summer? etc...

Next, do you want on-grid or off-grid power? On grid power with Grid Tied Inverter is about 77% efficient (wrt solar panel name plate rating + GT inverter losses; and off grid power is roughly 53% efficient (need more panels to drive the same load).

Where are you at? Naples Florida? Then use this link to calculate how much solar panels you will need (default is 77% efficiency which is good for predicting Grid Tied power). You will have to decide if you want the panels flat (less wind resistance, less power, more cleaning, works with boat not at dock in fixed position) or tilted (more power, self cleaning, but you need to point the boat in one direction during the day to catch sun) or adjustable/tracking (adjustable get optimum winter/summer power, tracking probably not for a boat).

And, since you now know how much power you need. Take your daily average and multiply it by 6x for the size of storage batteries (3 day of storage to 50% discharge level max for long battery life).

Size for the charge controller (MX60 type MPPT). Pick voltage (12 vdc OK for low power systems, 24 vdc typical for mid sized systems, 48 vdc for high power systems, least amount of copper needed for system).

Install it all and connect to your generator / battery charger and inverter...

Should about do it... Costs of off grid (battery backed) power, probably more than $1.00 per kWhr... How much is your power at the dock? If you go grid tie, you might qualify for Florida's $4.00 per watt (panel rating) rebate and cut your costs by 1/2 or more). Grid tie power costs with rebates, probably under $0.15 per kWhr...

-Bill

System2 · March 2008

Re: Marine applications

Thanks for the responses. Amount of energy needed will exceed any amount we can make with the panels and wind. So. We do need wind and solar and the alternator on the engine will have to make up the difference. The panels will mount onto a very sturdy "hard top" that does not flex so what I'm getting is any panel will work. Now... about the MPPT controllers. If we are not going with that type of controller, what voltage output panel should we go for. Available space is approximately 80 inches by 75 inches so a couple of 200 or 220 watt panels will fill the space nicely. Shading is always a question but when the boat is anchored and the boom is centerline the shading is not as much of an issue.

BTW anyone who can afford to keep a boat in Naples these days can afford the shore power!

heh heh Although I did spend a lot of time anchored out nearby in Goodland... probably one of the last little old Florida places we could still do that... sigh. This boat will be cruising in the tropics and the trade winds and will rarely be at dock. While at dock the Freedom inverter/charger takes care of all power needs.

With this new information... any more ideas? Still think the MPPT is a waste of time/money?

George

Solar Guppy · March 2008

Re: Marine applications

Mppt an hot tropical weather with shading is a waste of $$$. The panels when hot will be pretty near the optimum voltage anyways so no gain for mppt.

Get 12V panels, wire them all in parrallel to a Xantrex C40 ( get the optional display ). A very rugged and feild proven unit. Also the emi from a C40 is minimal as when the pwm kicks in for absorb or float, its at ~240hz

Most mppt units ( sans the Xantrex XW60-150 ) are very noisy emi wise and will likey cause issues with onboard radios

niel · March 2008

Re: Marine applications

thatboatguy,
if your needs are that great then you may need a bigger boat to put all of this stuff into. any shading will be a detriment to the pvs' output so that is also reason to scrap a wind generator that won't output more than pvs anyway. even going with the most efficient pvs it may not work for you if you can fit more of the lower high efficency pvs into that required space and the higher output pvs will have glass making them a bit more breakable too. you have me wondering if you aren't going to run a pirate shortwave radio station or something from the seas.

tourist,
if you got the money you can do it if you want to. i don't think you'll find a houseboat qualifying for rebates though.

n3qik · March 2008

Re: Marine applications

Instead of a C40, why not go with a C60 controller. This will give room to grow.

Solar Guppy · March 2008

Re: Marine applications

Yeah, the price differnece is so little go with the Xantrex C60 ( with display )

Telco · March 2008

Re: Marine applications

Too bad the flexible cells designed to be worn as clothing aren't available quite yet, you could oversew the entire sail with it and turn the whole sail into a giant solar collector.

If you are constantly cruising, but not in a race, is this an instance where a towed water turbine might work? I suggested this before for a racing boat, but that was voted down as too much of a drag, but for a non-racing boat might be worth investigating.

Marine applications

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