Only Solar

[schoonerdog]

sunpower is the best, but I don't think they are easily available from most solar panel resellers.

[FreeSail]

Has anyone noticed how much in cost a charge controller has jumped ? Three months ago many were below $300 now most are above $450.

[Pelagic]

Sorry Gord, didn’t mean to give you that editing work

The Sunpower A300 solar cells are actually made here in the Philippines and I can buy the finished modules via their Australian re-seller Solar Sales.


What I need to clarify with those of you with Solar experience is what are the priorities in making the decision on what to buy?

Is it temperature co-efficient or shading tolerance or should you just go for maximum efficiency which the SunPower seems to have.

The solar panels will be placed on a dedicated rack to be built above the stainless davits
That clear un-shaded area is approx 160cm long x 240cm wide.
Since I will build the rack to suit the panels I need to decide which modules to purchase first.

My goal is to maximise the amount of solar energy for that area in Tropical temperatures which would be used to feed my AGM house bank 24volts (total 1040AH)

My consumers are high so I am not expecting this to be my only charging solution but it should keep my 4 isotherm fridges from draining the house bank when no one is onboard

From the product range on the Sunpower website 3 of the Sunpower 215 would fit nice but I don’t know if that is the right choice?

My questions?

1) The 215 is not a nominal 24v but with MPPT controllers now is that still an issue?

2) If not an issue, which controller would you recommend for 3 x 215 modules for 24volt battery charging?

3 ) Is there an alternate solution that anyone could advise me of using different modules for that approximate area?

Thanks!

[hellosailor]

Follow the links to Sunpower's web site. They are targeting solar "roof tiles" and while they make a number of terrestial products--they offer none for marine applications or portable use. EL gives no crtieria for how "best" was designed, but in this (marine) market, Sunpower might be the WORST, since none of their products is for the market at all. (Bearing in mind, even some of the companies with long warranties for marine use, have cut them back radically after finding out how many panels fail in salt spray.)

[Pelagic]

Thanks Hellosailor,
I understand what you are saying that the manufacturers are not supporting marine applications any more.

So given that we are on our own….. what would be your criteria today in buying approx 5-600 watts of Solar panels to fit into the space above these dingy davits?

The company voted by EL “best value” SunTech in China will allow me to buy direct (no dealer in the Philippines) and they have a number of products like this with 24v nominal output

http://www.suntech-power.com/products/docs/STP_260S_Vb_DEC_2007.pdf

What would be most suitable for our marine application in the Tropics?

[hellosailor]

I don't know who serves the Phillipines and have to think it is way cheaper to buy locally than to have panels shipped in to you. Either way, I'd look at the list of suppliers who are established firms (BP, Mitsubishi, etc.) and then from that list sort it again for who will offer a warranty in marine use. I think several of them still offer 25-year warranties for sailors.

I wouldn't be surprised if the Chinese produced "best value" in terms of dollar cost. There have been some recent horror stories documenting the way some of their solar panel plants have been dumping toxic waste--instead of paying for proper treatment and disposal of it, the way the competition does.

Even if I say "that's their problem not mine" it still could become my (your) problem, if the company isn't around to service that warranty, should you need it. Of course, if their panels come out to half the price of the others...it may be worth gambling.

Either way, you need to find out what's available locally, at what price.

[Pelagic]

Unfortunately, nothing in the Philippines is established as those who know this entertaining country are familiar with their national mantra…. “Sorry sir, out of stock!”

No dealerships have evolved as not enough of a market (other than foreign subsidized solar projects that line the agents pockets) so I pretty much have to bring in stuff from overseas, with China or Japan being the closest.

Getting back to priorities: (obviously due diligence in finding a manufacturer with a decent reputation)
· Choosing 24v nominal output?
· Choosing the best for high Temperature conditions?
· Choosing one that will be tolerant to some shading?

How should I prioritize these elements if efficiency was about the same?

[hellosailor]

24v output will give you higher efficiency (on the order of perhaps 2%) with an MPPT controller, compared to 12v. But, two 12v panels give you better odds of redundancy in case a panel fails, and full output from one if the other is shaded. 24V also means you can use thinner, lighter, less expensive wiring, but again not a HUGE difference in the whole system. I'd say flip a coin, 12-vs-24 is not a deal maker or breaker.

High temperature performance should be comparable from the makers' technical data, a good point for you. Possibly the #1 issue for you, if the charts show any real difference. I suspect you'll find temperature/vs/performance is a fixed issue based on the chemistry of the panel, and falls into about two camps, along the same lines as "crystal/vs/amorphous" if there's much difference at all.

Shading may be more important if you're constantly going to have the shadow of the boom or the sails over the panels. Best way to do that is to observe the mounting location, maybe check it every 1/2 hour and make a note in a notebook, while you've got a strip of tape marking off the future panel area. Shaded, or not? How much how often?

IOW, see which parameters matter the most for your boat--then see how the different panels rate for them, and which will mean the most for you.

[colemj]

Pelagic, I am reading your requirements as you having a 24V house battery system. Is this correct? If so, you will need panels, or a panel setup, that supplies >24V to charge your batteries. A nominal 24V output will not work for charging a 24V system. For comparison, charging a 12V system requires panel voltages of 15-17V.

Mark

[hellosailor]

24V house system? Ah, I missed that. Definitely a nominal 24V panel array then, keep the same nominal voltage all the way through, it makes life simpler. (An MPPT controller with 12v input can have a 24v output, but somewhere down the line I'm sure that's laying landmines for yourself.)

[ronniesimpson]

My electrical set-up consists of the following:

4 80W Solar Panels
1 Wind Generator
55 Amp Alternator on my inboard diesel

12- 6 Volt 245 Amp Hour Golf Cart batteries

My boat is at the marina right now, while I am preparing to cruise, but I am not plugged into the dock. (3.5 months now, no shore cord) This setup rocks the house and provides plenty of power for my 41 foot Bounty 2. I watch DVDs at night, play playstation, leave the lights on and run my stereo non-stop. I also enjoy ice cold refrigeration, and frequently use power tools when working on the boat. If anyone is looking for a good, self-sufficient set up, this would be a good route to go.

[ronniesimpson]

here is a picture of my set-up. It is an aluminum rack on the back, made of welded alumnium