The real cost of solar power?

[Sandero]

Alan,

What is a BIG engine? Where do you see the size when using a inboard diesel for generating electricity would make sense? The need for a genset usually means lots of electrical loads and this means a larger tricked out boat.. which would probably have a BIG diesel... no?

Perhaps a 25-35' boat doesn't even have all the electric loads, not the space for a generator and probably as a little engine.

No?

Jef
sv Shiva
Contest 36s

[coot]

Originally Posted by defjef

I am not sure why people who need power don't run their main engine... charge the batts, make hot water...

We have been assalted too many times by gensets and I have a severe alergy to them and the disturb my naps and my dinner and the quiet of the harbor. I think they should be prohibited or required to meet a sound limit. They do make insulated enclosures for them too.

I have a 54 HP main engine and a 4.2 KW generator. The main engine is substantially LOUDER, makes a greater volume of exhaust, and produces less electrical power (and therefore takes longer to charge the batteries). If you would be disturbed by my generator, you * really * don't want me using the main engine.

[hellosailor]

"What is a BIG engine? "
Aye, it's not a BIG engine unless you can stand up inside the cylinders, without taking your hat off.<G>

[Alan Wheeler]

Well.... I guess for me it's like this. I have a Perkins 6.354 as the main engine. I have a 5KVA genset. The main engine is going to use ruffly 8ltrs an hr at a high idle driving a generator. My 5KVA genset is a small single cylinder that runs on the smell of an oily rag. It costs only about $2K to replace. It' wouldnt even be worth rebuilding. Replacement is four easy to remove bolts and it lifts out and a new one drops straight in.
My main engine would cost a minimum of around $10K to rebuild and replacment would be $50K or more. It would take huge effort to remove with partial removal of the pilot house roof and a crane to get it out to rebuild. Personly, I would like that to be many many years away. The less I use the main engione, the better for me. So it just comes down to economics.

[Sandero]

Alan,

Fair enough... and how long can we expect a diesel used and not abused to last? Mine (36hp volvo) has been going for 21 yrs and I only last year had to do the top end. She's starting harder now, but when she's warmed up runs great and I DO use the engine for a batt charge, frig cool down and to make hot water on a daily bases when I am onboard.

My frig is engine drive and so is my hot water so a generator would do little more than top up the batts. Therefore it is not a good solution for ME.

If I had a 12v frig and another means to make hot water, I could ONLY use the engine for driving the prop! Not gonna happen. If I get 10yrs more out of the engine.. it has like I think 4,000 hrs I would be very happen and probably dead before the engine! (the ways things are going)

Jef
sv Shiva
Contest 36s

[hellosailor]

Jef-
"Fair enough... and how long can we expect a diesel used and not abused to last?" A good million miles with routine maintenance, about 15,000 hours, supposedly. In sailboat use...I hear 5-10k is more likely though. Assuming you can find an engine with an hour meter on it!

Wheels, who cheaped out and built your boat without an access hatch for the engine room?! (Never heard of Hartley on this side of the puddle.)

[Strygaldwir]

Originally Posted by hellosailor

Rossir-

Keith-
"I only saw full rated output for about 3 hours a day in the Bahamas." WOW. Only three hours?!

Yes! Only 3 hours. The issue is, our panel is mounted in a horizontally fixed aspect. So, we get rated output only when the sun is close to directly overhead. That's the bad news.

The good news is it produces usable energy over a lot more hours than I had expected. We got exceptional output over about a 6 hour period (I didn't run numbers, but my guess is about 85% of rated output), and we saw some output over more than a 12 hour period. The less than great news is that we have an MPPT controller that is largley responsible for the extended out put. In our case, that was a $350 option.

[rleslie]

Originally Posted by Strygaldwir

Yes! Only 3 hours. The issue is, our panel is mounted in a horizontally fixed aspect. So, we get rated output only when the sun is close to directly overhead. That's the bad news.

The good news is it produces usable energy over a lot more hours than I had expected. We got exceptional output over about a 6 hour period (I didn't run numbers, but my guess is about 85% of rated output), and we saw some output over more than a 12 hour period. The less than great news is that we have an MPPT controller that is largley responsible for the extended out put. In our case, that was a $350 option.

My experience with output and MPPT controller mirrors yours. We can adjust our panels but rarely do. Economically, solar is expensive. However, we are willing to pay the extra cost (above that of running our generator) to have the peace and quiet. Three days in a beautiful anchorage with no noise = priceless.

Roger

[maxingout]

Cost is only one part of the equation when you make decisions regarding the best way to generate electrical power for your yacht.

If you spend your sailing life in the tradewind belt anywhere around the world, you have almost unlimited energy at your disposal. You have both solar and wind power.

I have four solar panels that are now around twelve years old, and when I am in the tropics, I count on them to supply about 50 amp hours a day as long as it's not overcast. That just was not enough power for my catamaran without having to run engines to generate electricity.

I put one silent Aerogen 6 wind generator on my cat in New Caledonia, and to my surprise I went for six weeks without having to run my engine to charge my batteries. The trade winds were really pumping in New Caledonia.

When I decided to complete the last half of my circumnavigation with two more people on board using electricity for computers, autopilot, and other stuff, I added a second aerogen 6 windgenerator.

With the two aerogen 6 wind generators we had tons of power. In the tradewinds, we could get 300-400amp hours each day out of the wind generators when they both were working. Sometimes we would even feather one of the wind generators out of the wind because the electricity was just going into the dump resistors when they both were running. But when we had a couple of computers running, refrigeration going, running lights going, radar on, and autopilt working around the clock, those two wind generators did a fantastic job and there was no need to use the engines to generate electricity. I got to the place where I regarded my solar panels as a back up system that was there in case everything else failed. At least I could put some juice into the batteries to maintain radio communications and essential electrical devices if other electrical systems failed for some reason.

Generating electrical power on a sailboat isn't cheap, but most of the expenses are upfront expenses that you absorb ahead of time. If you know that you are sailing to remote locations where there will be lots of wind and sun, and if you know that you are going to be doing it year after year, then solar and quiet wind generators are hard to beat.

But if you are going on shorter cruises in less windy and sunny climes, then I wouldn't invest in wind or solar. For me, it would be a waste of money, not to mention the fact that my boat would probably look better without the solar panels and wind generators attached to the boat.

I do confess that I like having the two wind generators when sailing offshore. They keep me honest when I'm on watch because I look at the wind generators to see what is happening to the apparent wind. Those wind generators are always telling me what's going on without having to look at my calibrated wind instruments. It's just one more way of keeping track of how my catamaran is interacting with the wind and sea.

Cheers,

[CSY Man]

The less than great news is that we have an MPPT controller that is largley responsible for the extended out put. In our case, that was a $350 option.

Ya got a link for that MPPT controller?

Thanks

[roverhi]

MPPT controllers work great with identical multiple panels. Here they don't work much better than regular controllers with different sized panels. What is the loss in efficiency of MPPT controllers with mis-matched panels. Does it mean I'd have to sell my existing panel and replace with identical panels if I wanted to up the solar generation capacity with an MPPT controller.

Aloha
Peter O.

[rleslie]

Originally Posted by CSY Man

Ya got a link for that MPPT controller?

Thanks

Blue Sky Energy INC. - Solar Boost 2000E

[Strygaldwir]

Hmmm.... I have an Outback MPPT controller. It does not require the same panels. As a matter of fact you can even mix and match them in series and parallel. You just don't won't to exceed 100 volts of input, otherwise, the recommend additional controllers.

A google search on Outback MPPT or just MPPT solar will get you LOTS of hits.

[schoonerdog]

Regarding output, I lived at anchor being solely supplied by solar from the Chesapeake to Cuba and back for a year from 2001 to 2002 and carefully checked outputs. A basic rule of thumb I've personally come up with is for non directed panels facing straight up with no shade divide the panel watts by 3 and you will get a rough idea of the total amp hours you'll get per day. So 700 watts of solar panels will provide around 230 amp hours per day on a sunny day. From those latitudes (annapolis to cuba) if this total output of 230 amp hours is around 25% more than your daily consumption, you should have adequate power for rainy days, cloudy days, etc. My daily consumption is around 180 Amp/Hours so the 700 Watt array supplies enough power on balance for the entire year. This is living a full year at anchor in different places with just the solars providing power. I measured output during typical cloudy/rainy days we were producing still around 50% of the 230 amps, around 115 amps. During deficit days we still have enough power for refrigeration and freezer and can reduce lighting by using LED lights and still charge our batteries at nearly 100%.

[GordMay]

Originally Posted by schoonerdog

Regarding output,... A basic rule of thumb I've personally come up with is for non directed panels facing straight up with no shade divide the panel watts by 3 and you will get a rough idea of the total amp hours you'll get per day ...

Which roughly equates to the 4-hour rule of thumb ~ 12 Hrs of daylight / 3 = 4 Hours of output. Actually, your observation would more closely equate to an assumption of 3.5 hours peak output, depending upon latitude and season.