effectiveness of solar & wind

[sailaway21]

I am pretty sure I have read about the decreasing efficiency of solar panels with age. And while it might take twenty years to fully deplete their effectiveness, I doubt many will find them desirable at 50% effective. In the quantities needed to produce significant power I think their margin utility is questionable. Probably explains why all our roofs are not covered with them.

The Honda does offer a lightweight and quiet alternative that cranks out 'reliable' amperage without the fickleness of the sun. I would expect it to last as long as the average boat motor. My 20 year old Honda lawnmower is currently sitting out in a semi-marine environment, albeit frozen, and I fully expect it to answer the bell as it has for the last twenty years.

All of the ocean racing teams are using water generators and I find it surprising that we hear little about them here. They offer a good amount of amps and minimal drag on the boat. They seem to be the best form of "free" energy. But of course you need to be making way to use them. Between the wind generators and solar panels, not to mention the wind vane steering, some boats are starting to look more like "Ice Station Zebra" than boats.

Here's an idea to get the dog scratching his ears: with all that lead we are hauling around in various designs of keels it occurs to me that we've got about 75% of a battery's components bolted to the bottom of our boat. Any thoughts on replaceable keels for mass produced cruising boats? Every ten years you replace your keel and recycle the old one? That would be a heck of a storage cell. Not the least of which we could combine the fin versus wing, and series versus parallel debate into one thread. Maybe this belongs over in "Perfect Boat".

[Cruisingdad]

sailaway,

As far as the keel... you laugh, but some aspect of that could be plausable. Why not? Of course a hard grounding would not be pretty for the environment, especially if it was battery acid spilling onto a reef.

As far as the wind generator, as a liveaboard/cruiser, I will tell you why it would not work well for me: you have to be moving! We spend the majority of our time anchored somewhere and exploring. Both wind and solar are passive and work in either environment. Water gens make a poor solution for the typical cruisers I know. THe racers are not anchoring for weeks on end somewhere (well, hopefully (smile)). They are hauling butt to cross the finish line. Thus, a water gen is a better solution.

Here is another "fun" little exercise we can play with. No one take any offense. THis is just quick numbers I threw out:

My solar cost me (even adding in the wire and radar arch and everything): $7,500. Sounds like a lot of money for something that only puts out a budgeted 150 amps/day. Let's cost compare that to a generator, the cheapest one we can.

Wind: For the sake of argument, let's say it is only 80% efficent, only works 80% of the year, and only runs for 80% of the years they say it will. THat means that my amps/dollar = (150ah*.8)(365days*.8)(20yrs*.8)/$7500. THis equals 560640 (total amps)/ $7500 (total cost). That equals 74.75 amps/dollar.

Generator.

Let's not use a "real" marine generator like a Fisher or Mastervolt or Westerbeke. They are a solid $15,000 and solar would blow them away. Let's use a Honda generator (as was your example). Let's say you find it on Ebay brand new and ready to go for $800. Let's say it is the new and improved model and never needs an oil change, never needs any maintenance, will never break down, and does not need any special cords to connect - basically, it comes straight out of the box and runs for 20 years without anything but gasoline. Let's also assume gasoline never goes up a penny. It stays at @2.50 forever, no inflation. Let's say you have put the coin into your batery system and only have to run your generator every 3 days for a gallon a day (4-6 hours on a gasoline generator at 1 gallon total).

In order for that same generator to compare to the solar, it will have to run for 80% of 20 years. It will run every three days. It's comparable cost is $800 for generator + $2.50 (cost of gas) * 16 years (number of years it will run) * 365/3 (days in the year/# days it will run). THis equals:

$5,666.67 to run your generator. You will have purchased 1,946.67 gallons of gasoline. In the end, your generator is cheaper by: $7,500 - $5,666.67 = $1,833.33.

Now, what happens if you take out the cost of my radar arch from that equation? Many people do not go to that expense. They simply strap them on the top of their davits or their stanchions. Many people get arches and never even go solar - so was that completely fair?? That means the new cost comparrison is ($7,500 - $3,300) - $5,666.67 = ($1466.67). That means the generator cost you $1,466.67 to run. You just made money on solar.

Now, what if you DO have to change the oil on your generator? WHat happens if you DO have to service other parts? What happens if gas DOES cost more that $2.50 gallon over time? What happens if you DO have to run it more than once every 3 days? What happens if it DOES burn more than a gallon every 4-6 hours? What happens if you DO get bad gas (come on, be realistic... I sure have gotten bad gas). And let's not forget this:

RRRRMMMMMMMMMMMMMMM in the middle of a quiet anchorage. THe birds fly off. THe fish find another home. Your neighbors hate you. The vibration. The nasty fumes. And most of all: YOU HAVE TO BE THERE THE WHOLE TIME, EVERYTIME, YOU WANT THAT POS TO CHARGE YOUR BATTS.

Nah. I have been around too much. I hate those things. THere are other benefits with going with a generator (kinda like, running your air conditioner, which is why I have a diesel genny that is quieter and more efficient and does not require my boat to be lined with red gerry cans down both sides eroding with the sun). But, there are many positives to solar too. The initial bill is tough to swallow. The catch phrase is IF you keep your boat that long. Almost none of us do and will NEVER realize the cost benefit of solar. Thus, they should go green for the other reasons mentioned.

This was just meant as a fun excercise, so please take it as such. We can nit-pick each other on the details, but I have tried to be more than fair (or at least I thought I have). Is solar worth it?? That is what each person has to decide for themselves, I guess.

Smile.

- CD

[cpcohen]

Solar panels _work_ on any boat. They are not a "complete solution" for most boats.

From experience -

We have a Morgan 36 Out Island, without refrigeration. We have a computer, heavily-used SSB, mix of flourescent and incandescent cabin lighting.

There are two 55-watt panels on the hardtop, and one 75-watt movable panel, usually on the lifelines or foredeck. No fancy mounts.

Solar-panel regulator is a Xantrex Trace 12 (I think) -- PWM-type, user-settable voltage. [PWM regulators need lots of ferrite chokes around them -- otherwise, the SSB is unusable during the day.]

The engine alternator is rated at 55 amps, and I run it at below 50. There are four golf-cart-size 6-volt deep-cycle batteries (two Rolls, two off-brand).

In west-coast Mexico and Costa Rica, at anchor, we ran the engine once per week for a few hours.

The solar panels were very, very useful. They didn't supply _all_ our power needs, but they did a lot to reduce engine-hours. I love them.

Your results may vary. We were in very sunny, low-latitude locations.

Charles

[Cruisingdad]

Charles,

Are your panels connected in series or parralell? If series, can you connet another panel, onle larger, to help replenish more of your juice? WIll your charger support it?

A nice thing about the MX60, for example, is that you can use multiple panels of varying size. They are all wired series. It takes the volts and reduces down to your bank volts with applicable current. Thus, adding more power to your system is as easy as buying another panel and putting it into the system. You basically have nothing else to deal with: a panel plus accompanying wire.

Just thoughts.

- CD

http://store.solar-electric.com/outpowmxmp.html

[Idiens]

Thanks for the good thoughts CD.
I have my heaviest electrical load at night en-route: nav-lights, autohelm, radar, classic instruments, FLS, cabin lights, etc.. That's where I see a towed generator having some advantage. Currently, I just run the engine occasionally to recharge en-route, plus a bit of solar during the day.
I don't want to run my Honda genset, it makes more noise than the engine and produces less power, plus I don't have a good stable location for it in a seaway. I have only used it when moored, with it at the furthest end of a long extension cord and when I had dying batteries. So it is really ballast. I suppose with aircon and deep freeze in a hot climate, a built-in soundproofed genset may have something going for it.
All the wind generators I have heard of - I have heard, on other boats, in the dead of night, maybe someone makes a really silent one.
Fuel cells are coming onto the market, they are supposed to be quiet, but the current ones guzzle a lot of something odd, the most acceptable being camping gaz. Perhaps they are the future for the gensets.
I wonder about having two big alternators on the engine and a suitable charge controller with big AGM batteries. For coastal hopping, the engine usually gets run an hour a day. With a couple of 110 A alternators, theoretically one could pump 200 Ah back.

[Cruisingdad]

Idiens,

If you are running your main to charge your batteries, it is tough on the main. However, while underway, why wouldn't you??? I think Balmar has the market on this, with their correponding 3stage charger that connects to their alternator. I was reading in CF that their low end (100amps) are really made cheaply, but I cannot comment. I would hesitate putting a really large one on my engine (other than the fact I do not need it) because of the power loss.

As far as making a passage... all bets are off. A water gen could be awesome in thos circumstances. My electrical usagae goes way up offshore because of radar, chartplotter, autopilot, etc. I am assuming others have the same problem. Using a system that connects to the prop shaft and spin it (like the lagoonn 420) would be nice in the future.

Regarding a diesel generator, like a Fisherpanda or a Mastervolt, I can comment on both as I have owned (1st was a FP, now a MV) both. They are quiet and just sip the diesel. Very effiecent and I could run my fp in an anchorage and you would never know it. It had plenty of power for one 16k btu ac and full battery charger or full batt charger and hot water heater or full batt charger and mw. Other combinations would shut it down. The MV seems a bit different. It will take an overload, but will shut itself down when it starts getting hot. It likes to run at about 80%. However, comparing a 15k Mastervolt diesel generator to a gasoline honda is apples and oranges, so I will leave it there.

- CD

[camaraderie]

Idiens...two big alternators on most sailboat marine engines will prematurely wear out the bearings due to load and side pull needed. Thats 8HP to drive them too!!

[Idiens]

HI CAm - I'm surprised Yanmar sells the kit then - but maybe they sell more engines that way

[camaraderie]

Yup...when you go to a double belt rig and have that much HP pulling you have a tremendous side loading cause te second pulley is further out on the shaft too.

[christyleigh]

Originally Posted by camaraderie

Yup...when you go to a double belt rig and have that much HP pulling you have a tremendous side loading cause te second pulley is further out on the shaft too.

Cam - I would think that if you have the engine room - room with some creative idlers to get the two alts as close to pulling 180 degrees from each other as possible you could pretty much negate the bearing issue. Also if you have some HP to spare such as on a motorsailor it may be a winable situation. I'm pretty sure I have read out on the NC list about some who have 2 running. I'm not saying they are not doing some damage or that it is necessarily a win - win situation but I just wanted to throw that out here as a little more food for thought