Help Me Plan Out a Solar Installation - Page 2 - Boating, Sailing and Cruising Forum: For Cruisers

Maren · #11 (**permalink**) 06-18-2009, 10:23 AM

Quote:

Originally Posted by Sully

A very interesting and varied set of replies. Thank you to all.

I am just learning about solar in many ways, so a lot of this reading was helpful. I didn't know if the panels could be daisy chained, now I do - knowing I have to watch out for over voltages on my charge controller. I'm learning.

Also, Whimsical has a good overall idea there that I hadn't even considered. I wasn't considering breaking my idea of how to charge into bulk, absorption and float stages. Genius! This is probably the best way to think about it. It make perfect sense to allow the batteries to drop to 50% on the worst of the worst weeks and use something with more heft to charge them at that level because they will accept a charge faster. This is brilliant! Thanks!

Thinking along those lines, I don't need a Honda at all. All I need is (didn't scallywag say this??) a cheap bulk charger hooked up to my current genset to dump any/all power from it right into the batteries.

My boat is set up as a 12V boat (12v refer, 12v everything), so I have to go with keeping batteries topped off rather than say, an engine driven refer.

Maren, you did interpret the post correctly. I had only run into a little spot of trouble in FL one week where it was very cloudy and hot. Other than that, I haven't had to use the current generator at all. Also, this year we will be going South. We're not wintering over. The wife wants to be warm.

I will give this some more thought... I enjoy keeping my batteries topped off at all times because I don't like buying new batteries. The extra solar would keep them topped off. I'm also with SanderO on not liking the noise of the genset or the gas, oil, used oil, etc... you have to store. We won't be tying up to any more docks for at least a year, since we are going South.

Guess I have to keep noodling this one out...

Let me ask a brief question: If you were to add another one or two batteries, would you solar/wind array be able to keep it topped off in decent conditions? If so, I would think that would be a decent solution, in conjunction with the above. Except for the detail of needing to keep all batteries of the same type and age.

Sully · #12 (**permalink**) 06-18-2009, 11:02 AM

Quote:

Originally Posted by shu

For myself. Since I do not have any solar at this time I will be getting some when I can afford it. Untill then and after if necessary, I will boost my state of charge with the onboard eng/alt. which makes more sense to me than spending a lot of money on something I do not normally need.

That makes sense for you, Shu. I understand. I look at it a little differently.

I tend to look at the "over the long haul" total cost instead because I'm trying to plan out for the next 10+ years.

Running my engine is the absolute most expensive $ per unit energy cost. It uses a good amount of diesel, uses the engine itself which would cost a fortune to replace, it's bad for a diesel to run without a load (glasses the cylinder walls), requires fuel filters, oil filters, going to docks to get fuel, belts, hoses, etc... etc... It makes sense in a temporary sense, like getting a loan does. But... you'll pay more over the long haul.

That's why the engine idea is wrong for my application. It's certainly the cheapest today, but in a couple years, the costs will kick in like a turbo. I'd like to save my engines so they last for the rest of my life. I have only a few hundred hours on them and with proper care, I could make them last a lifetime.

The engines I have now go for close to $10K a piece. Replace these in 5 or 10 years from running them with no load all the time and I'm looking at probably $15K-$18K a piece after inflation. $1000-$1500 for solar panels or $1000 for a Honda generator are both significantly cheaper.

Sully · #13 (**permalink**) 06-18-2009, 11:07 AM

Quote:

Originally Posted by Maren

Let me ask a brief question: If you were to add another one or two batteries, would you solar/wind array be able to keep it topped off in decent conditions? If so, I would think that would be a decent solution, in conjunction with the above. Except for the detail of needing to keep all batteries of the same type and age.

I suppose the answer would be yes, but only in ideal conditions.

I say this because right now I am increasing computer usage and as it is, the current setup gets into a declining charge over a week of bad weather.

What happens is I am short about 30-50AH a day in foggy/nasty weather. Over the course of the week of nasty weather, I end up going lower and lower, but usually recover. I just don't have the extra margin I feel I need to be working on my computer from the boat.

SanderO · #14 (**permalink**) 06-18-2009, 06:29 PM

You might consider an Asus notebook which is low power and cheap too. Laptops are great but they suck juice.

Felix · #15 (**permalink**) 06-19-2009, 08:20 AM

There's a simple, relatively cheap solution.

You say that you're 25% short on cloudy days. Get an MPPT controller for your existing solar panels. They really do boost the output 20-30%. I have the Blue sky 2000e for $220 that shows current into the controller and current out to the batteries.

Presto! Problem solved! :-)
just kidding, I know it's never that simple.

Tulliana · #16 (**permalink**) 06-20-2009, 04:08 AM

I would second the MPPT controller as we also have a Bluesky unit. The 2000e unit will only handle 350w so you would have to go for the bigger unit if you already have 250w and you want to expand on that.

It sounds as though you have similar weather there as we get here in the UK so its important you look at the nominal voltage of the panels. We are using 2off Kyocera 135w panels. The calculation of what to expect out of a panel is quite simple:
(Nominal voltage / Rated Watts) x hours of sunshine.
For the UK we use 4 hours, the Med 5 hours and the Tropics 6 hours.
On your 125w BP panel based on 4 hours a day you should get: -
(125w / 17.4) x 4 = 28.75 Ah per day / panel.
On my Kyocera 135w it comes out at: -
(135w / 17.7v) x 4 = 30.5 Ah per day / panel.
(These figures are estimates and any form of shading can cut them down dramatically)
Take a good look at the panels available in the market and do the above calculation before you commit to any new panels.

I'm no expert and have no affiliation with any of these companies but I hope the above helps.

It might pay you to work out an electrical usage sheet for your set-up. As a guide here is ours (its not an exact science, but I know ours isn't too far out) http://www.tulliana.adaero.co.uk/res...ower+Usage.xls

George R · #17 (**permalink**) 06-20-2009, 07:29 AM

Andy,(side note, off subject)
Great web site about your adventures. I like the spread sheet comparing the different cats.

Sully · #18 (**permalink**) 06-20-2009, 12:06 PM

Quote:

Originally Posted by George R

Andy,(side note, off subject)
Great web site about your adventures. I like the spread sheet comparing the different cats.

I'd have to agree! Great power spreadsheet and good ideas about MPPT controllers. I'll have to seriously look into this stuff. I guess I should put some more effort in to do this correctly rather than just doing a fudge factor.

Thanks!

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