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Discussion Starter · #1 ·
I'm in the process of designing a solar system to power an Engel refrigerator/freezer and keep a Group 27 battery (also used to power occasionally used inverter) charged.

I've decided on a 140W panel and am thinking of mounting it - independent of my bimini - on a vertical, twin pole platform that is about 1' aft of the stern pulpit.

The size of the panel is about 51 x 27. I was planning on mounting the framework to a piece of 1/4 or 1/2" starboard with on inverted deck flange at each end and then mounting the Z-brackets that come with the panel to the starboard.

The mount would be 7/8" stainless with the two vertical poles tied together with a horizontal brace.

Questions:

  1. Is the starboard desirable for having a rigid mount or should I just attach the solar panel to horizontal runs of tubing?
  2. Is it desirable to have whatever mount I use adjustable or is completely flat acceptable?

Murph

S/V Amalia
1965 Cal 30
Muskegon, MI
 

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Discussion Starter · #4 ·
With Paul & Ron's comments, and a bit of further research, it seems that there is no need to use starboard since the panel is well supported by just being mounted at the edges.

I found a website that offers lots of mounting options and will likely come up with something like they show.

While I can add to the battery bank and likely will, my loads are actually fairly small for a 140W panel. The Group 27 is 115 Amp Hours. At 50% charge limits, it could power the refer for about 6 hours with no input from solar.

Most solar planing says that 5 hours a day at rated output is what you can expect at average which is about 700 Watt Hours. Assuming 2.5 A with a 33% duty cycle, 12 V and 24 hours (about .8 Amp Hours per hour) it looks like the Engel will only need 240 Watt Hours for the whole day.

As to the inverter, that load is very intermittent and it will likely be turned off except when I need to use the microwave, coffee pot or electric tea kettle.

If I can, I'm still thinking about mounting it independent of the stern rail, but won't be able to really decide on mounting until I make the commitment to buy the panel, charge controller and the other stuff.

Thanks for your thoughts.

Murph
 

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Discussion Starter · #13 ·
As I get more into this, it seems like I will need to build a bigger bank with at least another Group 27 or go all the way to a Series/Paralleled bank of 4 T105's or equivalent.

Your comments and research on the charge controllers is fascinating; I hadn't really even thought about which controller I might use and this bears some further study.

How will I use the boat? Well, for the spring and summer, I'll be on shore power when I'm in the slip and the inverter will be off and Engle running from 110. I'll probably make a few weekend trips with whatever setup I have and make some measurements on how feasible it is to run from the second battery bank.

I have a primary house/starting bank of two Group 24's right now that are charged from an on-board charger and get a trickle from the tiny 35A on my Atomic 4. I don't plan on having any connection between this bank and whatever other bank I install as far as use or charging from the engine - but I may consider using one of my 3 legs on my 20A, 36V charger to top off the secondary bank when I'm on shore power.

Next September (God and finances allowing) I'm hoping to embark on the Great Loop and will be living aboard for up to a year. When I drop the mast and head over to Chicago, I'll be in for 1200 miles of motoring and will keep bank 1 topped of with the engine and occasional shore power charging. Using the Engel as either a freezer or refrigerator draws the same 2.75 amps on a (guessing here) 30% duty cycle and with minor use of the inverter as noted previously, think that this combination should do the job.

I really appreciate everyone's inputs. Like many other things in boating, adding solar and making equipment and use plans entails lots of research and decisions. I am grateful for the collective wisdom of the group.

Murph
 
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