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I just finished reading Sue and Larry's article about solar panels. A picture in the article shows multiple panels on what I assume is their boat. Some of the panels look as if they may be subject to shade during some part of the day. I am trying to determine what brand of panels they are using so as to not have problems with the panel efficiency degraded due to shading. Thanks
 

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George, to the best of my knowledge, there is no such thing as a panel not affected by shading. I use Kyoceras and have been very happy with them. However, they are affected by shading. The key is to choose a part of your boat where shading is minimal. You can also consider blocking diodes between multiple panels (assuming they are not already installed on them) so that one panel cannot pull off of another. I wired my panels in series to maximize voltage and minimize wire size. You will need to choose your controller before doing this though so you do not over-rate its capacity. I have used and been very happy with my Outback MX-60 (the most reliable piece of equipment on my tub). I have heard similar comments from other sailors that use their product.

Here is a pic. Note that I had to build an arch for my panels:

 

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Thanks for the reply and a couple questions.......

Looks like you have a nice setup. What size panels? How much do they weigh? What size are the tubes in the arch? Is the arch thru-bolted or otherwise stabilized? Where is the boat and how many amps/day do you usually get?
 

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Looks like you have a nice setup. What size panels? How much do they weigh? What size are the tubes in the arch? Is the arch thru-bolted or otherwise stabilized? Where is the boat and how many amps/day do you usually get?
Kyocera 130's (130 Watts/piece). I have 4 of them.

They weigh approximately 28 lbs without wiring.

The arch is through bolted with a backer plate and 4200'd to the deck.

The tubes are 2" in diameter. it is aluminum, not SS. However, I went with polished aluminum to make it look like stainless to match the rest of the boat. THe reason for this is it allows less weight aloft (88 lbs total, IIRC), is easier to tap (as I also use the arch for other things), and it is less expensive than SS. To get a 2" arch out of stainless, you will have a VERY heavy unit and very expensive. The reason I like the 2" diamters is for easy, multiple wire runs for multiple components.

On average, I get approximately 205-210ah/day from the units. Somtimes more, sometimes less.

- CD
 

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George, to the best of my knowledge, there is no such thing as a panel not affected by shading. I use Kyoceras and have been very happy with them. However, they are affected by shading. The key is to choose a part of your boat where shading is minimal. You can also consider blocking diodes between multiple panels (assuming they are not already installed on them) so that one panel cannot pull off of another. I wired my panels in series to maximize voltage and minimize wire size. You will need to choose your controller before doing this though so you do not over-rate its capacity. I have used and been very happy with my Outback MX-60 (the most reliable piece of equipment on my tub). I have heard similar comments from other sailors that use their product.

Here is a pic. Note that I had to build an arch for my panels:

There is one type of solar panels that are considered "shade tolerant" - which means they do not lose as much if covered partially.

HOWEVER, I will say this from experience that no matter what anyone says, if you partially cover ANY panel you will lose a significant amount of output, period.

Replacing battery power isn't magic either.

If you use 100 watts in one hour out of a battery, you need one full hour of sunlight on a 100w panel to replace that which was used. Or, you need two hours from a 50watt panel and so on.

That math isn't difficult.

Thats the basic stuff. Charge controllers are there to prevent over/under charging of batteries (over charging causes them to boil over, sulphate and ruin things underneath them). Under charging means you won't get as much energy for use next time.

CD is right - check your USAGE first, that is know your max amount of energy drawn in both minimum usage, maximum usage and EMERGENCY usage (using two radios on transmit, all your running lights and other electronics you might have on to keep you out of trouble!) - then base your equipment on the calculated use.

I do calculations on emergency electrical systems based on all emergency operation, then... I double everything. That means it usually costs a little less than twice what I thought it would :(

(I set up emergency battery power for systems all the time - but not on boats. On boats, energy is always at a premium!)
 

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Rick-

Your actually underestimating the panel size you'll need, since you're assuming no losses in the charging process and perfect efficiency from the panels... If you use 100 Watts of battery power, you're probably going to need 125-150 Watts of solar panel for an hour to replace it... :)

There is one type of solar panels that are considered "shade tolerant" - which means they do not lose as much if covered partially.

HOWEVER, I will say this from experience that no matter what anyone says, if you partially cover ANY panel you will lose a significant amount of output, period.

Replacing battery power isn't magic either.

If you use 100 watts in one hour out of a battery, you need one full hour of sunlight on a 100w panel to replace that which was used. Or, you need two hours from a 50watt panel and so on.

That math isn't difficult.

Thats the basic stuff. Charge controllers are there to prevent over/under charging of batteries (over charging causes them to boil over, sulphate and ruin things underneath them). Under charging means you won't get as much energy for use next time.

CD is right - check your USAGE first, that is know your max amount of energy drawn in both minimum usage, maximum usage and EMERGENCY usage (using two radios on transmit, all your running lights and other electronics you might have on to keep you out of trouble!) - then base your equipment on the calculated use.

I do calculations on emergency electrical systems based on all emergency operation, then... I double everything. That means it usually costs a little less than twice what I thought it would :(

(I set up emergency battery power for systems all the time - but not on boats. On boats, energy is always at a premium!)
 

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Rick-

Your actually underestimating the panel size you'll need, since you're assuming no losses in the charging process and perfect efficiency from the panels... If you use 100 Watts of battery power, you're probably going to need 125-150 Watts of solar panel for an hour to replace it... :)

no no, Not at all. I was merely showing the math. If you use 100 watts in an hour, it takes 100w (plus a little bit) in the course of an hour to put it all back, thats all.

But you're right. I was just showing the "simple math". (If you will note, I said I DOUBLE everything once I figure it out! :) LOL!)

So in my case, I'd be putting in 300w panels or something haha
 

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CD, forgot to ask........

would you happen to have any pictures showing how the panels are attached to the arch? Thanks for all the replys, folks!
 

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The tubes are 2" in diameter. it is aluminum, not SS. However, I went with polished aluminum to make it look like stainless to match the rest of the boat. THe reason for this is it allows less weight aloft (88 lbs total, IIRC), is easier to tap (as I also use the arch for other things), and it is less expensive than SS. To get a 2" arch out of stainless, you will have a VERY heavy unit and very expensive. The reason I like the 2" diamters is for easy, multiple wire runs for multiple components.

On average, I get approximately 205-210ah/day from the units. Somtimes more, sometimes less.

- CD
CD,

Great post, coinsidering I need to build something to support my Fourwinds wind generator. There's one aspect of this that I'm wondering about.

Would you still need 2" diameter if you went with Stainless, or would you pick up some strength from the different material? (Perhaps that would allowing you to go to 1.5 inches.)

Also, how long does the polished aluminum last? In 15 years what does it look like?
 

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CD,

Great post, coinsidering I need to build something to support my Fourwinds wind generator. There's one aspect of this that I'm wondering about.

Would you still need 2" diameter if you went with Stainless, or would you pick up some strength from the different material? (Perhaps that would allowing you to go to 1.5 inches.)

Also, how long does the polished aluminum last? In 15 years what does it look like?
No, you would certainly not need 2 inches for stainless. You do not really need it for aluminum either. However, I wanted the large diameter because it made it easier to climb on, easier for wire runs, the aluminum is easier to work with (tap screws), and there is a CONSIDERABLE price difference. If you want 2 inches on stainless, it would be very expensive.

My arch cost me, installed, $3,750 as I recall. That included the framework to support the panels. I am working off of memory, but that same arch at 1.5 inches Stainless Steel was a bit under $9,000 and the weight difference was considerable.

How will the aluminum hold up in 15 years??? I really do not know. I would assume it will start pitting at some point in time. However, aluminum in salt water is nothing new. Stainless is a better product, but I just did not want it for this application for reasons I have stated, the least of which was cost.

By the way, if you are considering putting on a wind gen, you might consider just more panels instead. My opinion. But I originally designed (and bought) this system to house both, and elected against the wind gen as it would shade the panels more than I would be happy with. Given the size of the array, I have no problem keeping up with my solar needs. My boat runs completely off of solar and has for 1.5-2 years now. The exception is air conditioning which requires a generator.

- CD
 

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Of course if it was stainless, it wouldn't have to be 2" in diameter to be the same strength. :)
 

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would you happen to have any pictures showing how the panels are attached to the arch? Thanks for all the replys, folks!
THose pics are on my other computer so I will need to just describe it.

I measured out the panel sizes. I had aluminum angle iron cut and welded to those sizes to full support the panels. THese were then welded to the arch. The panels sit down into the grid - each panel supported by a seperate grid.

- CD
 

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Cruisingdad,

Nice setup.. The numbers of 205 amp hours per day out of a 520 watt panel (ie, 4x 130) are pretty good.

If you dont mind, is this using a MPPT controller? What part of the country was it measured at and what time of year? (assume it was also measured with one of the xantrex charge monitors).

Note - I had posted here earlier about a rule of thumb of .234 amp hours per day per watt. Using this equation would only predict 121 daily amp hours for a 520 watt panel. So Im just trying get another data point...
 

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Cruisingdad,

Nice setup.. The numbers of 205 amp hours per day out of a 520 watt panel (ie, 4x 130) are pretty good.

If you dont mind, is this using a MPPT controller? What part of the country was it measured at and what time of year? (assume it was also measured with one of the xantrex charge monitors).

Note - I had posted here earlier about a rule of thumb of .234 amp hours per day per watt. Using this equation would only predict 121 daily amp hours for a 520 watt panel. So Im just trying get another data point...
Yes, I am using a Outback MX 60 MPPT. It calculates the AH it puts out to batts. That was measured in North Texas.

- CD
 
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