solar panels and refrgeration

[urisvan]

there are many solar panels with different labels on market. And the prices vary considerably. when it is called "marine" the price is twice.
what do you think about this subject? can i buy the cheapest one? or will it be corroded? what are the labels you recommend?
and what should be the power of the solar panels totally to supply a refrigeration?
and what should be the volume of the refrigerator for extended voyages?

regards
ular risvanoglu

[CDK]

If you watch closer, the difference in price is not that big. Monocrystalline panels should be compared with cheaper technologies and where you buy may make a difference because a lot of sources aren't satisfied with 25% profit.

Do not look around for marine panels, there are no such animals.
Solar panels from reputable makers like Siemens and Kyocera are used on houses, mountain tops and buoys at sea.

A good, compressor type 60 lt. fridge will run indefinitely on a 50 Watts Siemens panel and a 100 Ah deep cycle battery as long as you stay in the Meds. The same panel and an absorption fridge will leave you with lukewarm beer and an empty battery after a few days.

I once wrote a PC program that predicted solar performance based on latitude, panel direction etc., but cannot find it anymore. You should be able to find useful info searching for "solar panel calculation".

[urisvan]

hi CDK,
your words have heartened me. i was looking for more powerfull panels, like 180w for refrigeration supply.
i am looking forward for more replies to get sure about it.

regards
ulas

[CatBuilder]

Ulas,

The above reply is correct. While some panels may be labeled "marine", it doesn't matter. They are all the same thing. Also, most panels come with a 20 year warranty.

Don't forget you need a solar charge controller and a good battery bank to go along with your solar panel selection if you plan to keep your food fresh. Some days, you won't have enough solar power to run your refrigerator. Other days, you'll have too much. You need the batteries in the system to act as a buffer for these days.

A site you may want to look at to learn more about the refrigerator box sizing and the compressor sizing is: http://www.kollmann-marine.com/

Read through his FAQs and technical forum. Everything you need to know about refrigeration systems is on this site, and he is not a manufacturer of refrigerators or a vendor of refrigerator parts. It's unbiased information.

[Chuck Losness]

I have been cruising in western Mexico since 2006. I have an Adler Barbor super cold machine refrigerator/freezer. The battery bank is 420 amps (4 six volt golf cart batteries). The box is approximately 6 cubic feet. I started with just one 65 watt panel. This would just barely keep up the electrical drain during the day and I had to run either my engine or generator at least every other day. I now have four 65 watt panels which supplies all the power that I need. 3 panels may have been enough but I added the fourth panel just to be safe.

[urisvan]

thanks very much
in marine enviroment there is a fight against corrosion. so that was why i was thinking that marine panels could be better; against corrosion.
but you say that it doesn't matter.
won't it be any corrosion problem with normal solar panels?

regards
ulas

[CatBuilder]

Originally Posted by urisvan

thanks very much
in marine enviroment there is a fight against corrosion. so that was why i was thinking that marine panels could be better; against corrosion.
but you say that it doesn't matter.
won't it be any corrosion problem with normal solar panels?

regards
ulas

In my experience, I have not seen any corrosion on panels. The frames are usually built from aluminum. The panels are glass (the fancy stuff is encapsulated). There is some wiring and some electronics to balance loads in a small box located on the underside of the panel, but I believe this is well sealed off from the elements. The panels are designed to be outside all day long. Get good ones, with 20 year warranties and you'll be just fine.

[Alan M.]

Might be worth investigating the warranty though. A few years ago even Kyocera's didn't give the 20 year warranty if the panel was used on a boat.

[CatBuilder]

Alan, I saw that too on some, but I figured you didn't have to tell them you had it installed on your boat.

[Stumble]

The only difference I have seen between 'Marine' and standard solor panels is the use of tinned wires. Though nowdays I think all of the major manufacturers are using it on all of their panels.

[troy2000]

General question here, and I realize no one is going to be able to give me an iron-clad answer. I'm just trying to get a ballpark figure.

When I build my sharpie, it's going to have minimal electrical and electronic gear aboard:

a top-opening cooler or refrigerator, to keep beer cold and food edible for a long weekend. Nice but not required: enough ice-making capacity to allow a few 'on the rocks' after the sun is over the yardarm.

A masthead light for anchoring out occasionally.

Running lights that probably won't be used much, because come sundown I'll normally be pulled up onto a beach with the BBQ going.

Cabin lighting that probably won't be used for more than a couple of hours an evening, if that much.

A couple of 12-volt fans, to keep a breeze on the berths during hot summer nights.

Enough power to run a laptop for an hour or two of internet each day, and keep a cell phone charged.

Maybe something to play music a couple of hours a day, without any need to blast it out across the water.

Probably a CB or basic Marine VHF radio, for emergencies; maybe just a handheld. But no GPS, sonar, radar, depth finders, or other fancy equipment. I'll be on desert lakes, not at sea; how lost can I get?

Can anyone give me a rough guesstimate on what I'd need in the way of solar panels and batteries? I won't hold you to your answer; obviously I'll need to do some detailed planning on down the line. I'm just trying to get a very general idea, to help the preliminary budget.

I'd like to set a couple of flexible amorphous panels on the cabin top, if that'll work. And if push comes to shove, I do have a small Honda generator I could pack along to run a battery charger. But I wouldn't want to fire it up on a regular basis, if the solar stuff can do the job instead.

[CDK]

In my garden and driveway I have 4 Siemens SM-50, one SM-65, 3 solar roof panels for Audi/Mercedes and a dozen stainless steel solar lights. On the boat I have a Solarex flexible panel to keep the batteries charged throughout the year.

The location just a few steps from the Adriatic sea (3% salt), exposed to spray during storms in spring, 2700 hours of sunshine, any temp between night frost and 40 C.

The solar lights have been replaced several times over the last 10 years because the Chinese do not concern themselves with life expectancy. The plastic cracks or turns dark brown, the contacts corrode and even the polished steel shows rust.

I accept that because they are so cheap and easy to replace.

The solar roof panels are $ 2200 gadgets for expensive cars (I got them for free of course). They are approx 10 years old and have not deteriorated noticeably, but are poor performers from the start because the technology is amorphous. A 4rd one stopped working after a few months for no reason at all. You should only buy that if you have lots of empty space, so on a boat it is the wrong choice.

The Siemens panels are more than 20 years old. The German SM-50s have lost 10% of their capacity because the hi-tec resin surrounding the silicon wafers has gradually tanned. The anodized frames, glass and silicon cables look like brand new.

The SM-65 is a U.S. product without embedded cells. It performs almost like new (-3%) but small corrosion spots are visible on most wafers. Not bad after 20 years, but a sign that oxygen has found its way in. The frame is still in excellent condition.

And then the Solarex doormat. It is made from lots of tiny cells, so it is flexible, in a vinyl envelope stitched around the edges. Much abused because many people walked over it and it was blown into the sea at least a dozen times. After more than 10 service years it lost half its capacity, but I hold on to it because 0.5 amps is enough to keep the batteries fully charged.
It replaces another rigid Siemens panel that came loose during a storm, hit the sea-rail on its way down and shattered into a million pieces.

[Bglad]

Troy2000,

At first blush I think an onboard regenerative system will be overkill for the use you have planned so here are a couple of thoughts...

I think the biggest user will be your refrigerator and an icemaker will really chew up some current. If you build a well insulated ice box you can carry enough ice to hold your food and to chip off pieces at happy hour for drinks. After that I think it would be pretty straight forward to install enough batteries to use for a long weekend to cover the other loads you are thinking of. Work out the bank size so it doesn't go too low during each use and carry the back-up generator when you plan on going long.

Dock side or in the drive way have a battery charger installed to recharge so it will be ready for the next use. A minimal system would use a dedicated circuit strictly for the charger (essentially a hard wired extension cord) but with a breaker where it comes aboard.

I think the preceding minimize the complexity of the system. Also on a smaller boat solar panels take up space you might like to use for other purposes. If you just want some solar stuff that is another story although it would be kind of cool to last a whole weekend without any visible means of support (solar or otherwise)!

Let me know if the above sounds of interest. With a little more information from you I might take a stab at it for my own experience...

[urisvan]

thank you.
but it is not always possibble to find electricity on dock. And solar panels are also good for battery health.
i am planning to install a 80 wp solar panel and later when i have money i will buy a 35 lt refrigerator/freezer, i found one that exactly suit my space.
but i did not decice which charge regulator i need to buy. multistep regulators sounds good. do you have any recommendation?

[CDK]

Excellent plan Urisvan!
Buy a solar regulator with a temperature sensor near the battery. It automatically reduces the cut-off voltage when temp. is high.