Solar - Go Redundant or Go Big ?

[capt_douglas]

I'm about to place an order for solar panels for my T37 and after checking the web offerings one last time found:

Kyocera KD135GX-LBFS 135W solar - $353 - $2.61/W
59.1in x 26.3in x 1.8in - 27.5lbs

Kyocera KD225GX 225W solar - $596 - $2.65/W
65.4in x 39in x 1.8in - 46.3lbs

Obviously two 135W panels weigh less and take up less space than the 225W panel. I have space for either combination.

From comments here and around the web, the Kyocera panels have a good reputation for durablilty and performance, and a very nice warranty. The 225W panel is new while the 135 has a proven record.

Am I being too anal about wanting redundancy in going with the 2 135s vs the 225? Cost of installation is less with the 225 and wiring and regulation even out.

Given a choice, what would you suggest?

[Captain Bill]

Maybe I don't exactly understand what you are asking. Two 135 watt panels take up more space and weigh more than 1 225 watt panel, but also provide 45 more watts of rated power and redundancy should one fail. Also depending on your mounting situation they also give you more options for keeping at least one panel out of shadow on a tack, which can be quite useful.

[sailorboy1]

I don't think it's anal, I think it just makes more sense to get the 2 smaller panels if it's in your budget and works for installation. Other than than a little more cost; what to you is the downside of doing it?

[Unicorn Dreams]

I have 2-215W Kyocera's on my boat plus a KISS Windgen.

But I carry 10 6V 225 AH batteries in my house bank

[rebel heart]

The 2 135's. I've got the same setup (got them from altenergystore.com). Those puppies are humming away right now. If you get them from there, make sure you get the funky connectors they ship with, or just know you'll need to chop and splice with heat shrink butt connectors (I went with the latter).

[MarkJ]

Get 2 x 225's.

At $600 each they are money in the bank.

2x 135s are fine sitting on the equator but if you want a freezer you want excess electricity.

I have 2 x 120's and no freezer. Have to use my engine for an hour or so every other day (I'm at 28 deg N 1.5 months from the shortest day). With a propper size freezer in the Caribbean I think I would need 2 x 225's

The cordless drill batteries take forever to recharge, plus camera batteries, computer, shaver, video camera, handheld VHF, Cell phone, vibrator, the list goes on.


Mark

[shadow]

I would even consider a 3rd option of why not both, go big and redundant!! That is if your arch and budget can allow.. When it comes to power I want absolute redundancy.. I would rather have too much then always wishing I had more... Good luck regardless as your choices look great!!

[jcapo]

Shadows reduce solar panel output significantly. I'd go with the 135's for
redundancy and you will still have whatever output one panel can produce
for a given sun angle with a shadow on the other.

In the real world panel output is much less than the ideal conditions rating
by the manufacturer. I have 6 65 watt Kyocera's. Today at noon in South
Florida with the Sun getting pretty low in the sky, my panels gave me a bit
over 15 amps into the batteries at 13 volts. That's about 50% of the array
rating at peak sun. I have two Morningstar MPPT controllers with 3 panels
on each controller. The controllers say they generated 80AH so far today
with some morning shadows from the ketch masts and rigging on the boat
in the next slip to the South.

Fit as many panels as you can!

John

[rebel heart]

I think he was deciding between a single 225 or two 135's.

[MarkJ]

Originally Posted by rebel heart

I think he was deciding between a single 225 or two 135's.

Shhhh! I'm on commission from Kycoeria!

[cfarrar]

All else being equal, two smaller panels (in parallel) are better than one because they will tolerate shading better.

[GordMay]

Like Marc & John (et al) opined; I’d also go with more (2) of the largest (225W) panels I could afford & fit. There’s many luxuries I’d forgo to increase my electrical capacity.

[Bash]

Originally Posted by capt_douglas

The 225W panel is new while the 135 has a proven record.

Solar panels are such an emerging technology that every iteration is a bit more efficient than the last. If you do the math on those two panels, you'll see that it takes the 135W 11.51 square inches of panel to produce a watt of power, while it only takes the 225W 11.33 square inches to produce the same amount of power.

New is good.

[Surf City]

I was also looking into the kycoera 225 and Sanyo 205 HIT "B" panel for the same money. They say Sanyo is 10% more efficient at higher temps but it is a grade "B" panel. The "B" may be a blemish on the frame or cell but not effecting the production of power and still has the same warranty. But the warranty for both is not covered with salt spray. The Sanyo panels weigh less and are smaller in size when you compare equal wattage.

Does anybody have any thoughts on the Sanyo line of solar panels?

Wil

[witzgall]

Whatever you choose, make sure you can get it down the companionway, and secured somewhere on the boat, unless you are only cruising the coasts, and can take them home when needed.