Saturday, September 14, 2019

Another Ten-year Project

Well, almost ten.

Way back in 2010, I bought a pile of 6" square solar cells, with the intention of making a bunch of solar panels.  I had no idea that it would take me this long to finish this effort.  This was a low-priority project, dependent on acquisition of used shower doors for free.  Thanks to craigslist, I was able to find the necessary shower doors, but this took way longer than I anticipated.

Nevertheless, finished it is.  By the time I had built 5 panels, the remaining cells I had were not enough to build that sixth panel, due to breakage in transit, breakage due to my clumsiness (these things are *fragile* - in comparison, a potato chip is way robust), and missing collector busses.  The seller had included extra cells to cover breakage in transit, but sadly none to cover for my clumsiness.  I might be able to resurrect those cells with missing collector busses, but I don't know if that would give me the required 40 cells.  So for now, I am finished.

For each panel, no-load output voltage (at zero current) is about 22V, and short circuit current approaches 8 amps, as advertised.  But as I have mentioned earlier, you don't get to have short circuit current and no-load circuit voltage at the same time.

Something else I have learned is that the output of solar cells is temperature dependent.  The cells produce significantly more power when they are cool than when they are hot.  And that dark color means that they will be hot in the sun.  The highest output I have seen from my array is on a day that is mostly cloudy (panels are shaded), when the sun breaks thru (panels are in direct sun, but still cool).

So, a realistic assessment of the power output from these panels is about 100 watts each, at our lattitude.  This means that I have the capability to produce a little more than 500 watts (including the three little panels that came with Eolian when we got her).  That power is directed into a grid-tie inverter...  there are no batteries in our system.  In essence I am using the power grid as my battery bank.  The inverter turns the output of the panels into 110V, 60 Hz and pushes it back into the line, synced with the line power (if the line power disappears, say during a storm, the inverter automatically shuts off to prevent back-feeding the line).  If my home is drawing more than 500 watts, part of that draw is supplied by the solar panels.  On the other hand, if the house is drawing less than 500 watts, then the solar panel system runs my electric meter backwards.  (With a maximum output of 500 watts, I don't think I will ever need to worry about what happens if I end a month with a negative meter reading.)

Sadly, the day that Jane and I got the last panel up onto the roof of my shop was the first day of the fall rainy season.  I have yet to see what the finished system can deliver in sunshine.  Nevertheless, it feels good to tie the ribbons on another long term project.

(The remaining posts on this project can be found here.)


Saturday, August 3, 2019

Drip... Drip...


"What was that," Jane asked.
"I think the water pump just ran," I said.  "It was probably just on the verge, and a little leak back caused it to cycle," I said, hopefully.

15 minutes later...  Brrrrrp...

"OK, no one is using water and the pump just cycled twice.  Either we have a leak somewhere, or the pump is failing."

Hoping for the best case scenario (meaning I would not have to replace the pump...), I started at the bow and checked for water running aft in the bilge.  I didn't find any until I got to the last floor panel.  Yup, there it was:  drip, drip, drip.

Great!  It's not the pump!

But where was it coming from?  Best bet: a cracked fitting.  But where?  I could sort of see the general area where it was coming from, but serious boat surgery would be required to access that area.

Now those of you that don't own boats might be surprised to hear that there are quite a few places on boats that are either inaccessible or nearly so.  Boats are more like modern cars than those from the 50's and 60's.

So.  I began unloading and disassembling the flooring in the cabinet opposite the refer.

Getting access to the area...
I have been in this area before, but not as fully as this job was going to require.  Yes, I could now see the water actually dripping.  But the source was still hidden up inside that rectangular opening down at the bottom of the area, where the gray water lines are going. 

Deep dark hole...

I stuck my phone down in there and took a blind picture - yup!  Got it!  I even caught a falling drop of water in the air!  See how the left hand fitting is cracked?  That's where the water was coming from.  The fitting on the bottom of the tee is cracked too, but strangely not yet leaking.  Both of them need to be changed.  (The fitting on the right had already been replaced - it had a price written on it.)

I should point out that this space is at the aft end of the engine, and that when I finally got up the courage to dive into the job, standing on the engine mounting bunks, my shoulders were about level with the floor in front of the refer.  Deep.  And narrow - only a little wider than my shoulders.  And filled with hard things that hurt when bumping or kneeling on them.  In the end, I ended up kneeling on the engine bunks, straddling the shaft, and putting my legs back (fwd, actually) alongside the engine to get low enough to work in the opening.  Barely.

Once in position, and with good planning having the correct tools at hand, the job didn't take too long.  The hardest part was tolerating the pain in my shins and knees, knowing that it would all be over soon.  Voluntary bruising, the price to be paid.

These are the bad guys
When it was all done, I awarded myself with a beer in the cockpit, while waiting for the pump to cycle.  Hours later, it still hasn't.


Saturday, July 20, 2019

Leaning Tower Of....

Once again, crabbing has been good this year.  This is just three days catch - Jane likes to stack them up like this.  We have added so much to this that I am tired of crab for dinner...  Jane, infinite patience that she has, has picked most of the meat from these, and the many since these, so that we can fit it in the freezer here on the boat.


Sunday, July 14, 2019

A Tale of Two Tread Plates, Update

OK, it's now been two years since the original experiment...

Here's how they look now:

As you can see, the untreated tread plate on the left is still groady... in fact it is even worse in real life than the picture shows.

And on the right is the plate which was treated with BAC, still looking clean, tho grey.  I said BAC, but for this experiment I actually used a version of BAC that has some silicone functional groups substituted for some of the carbon-based groups.  This version, called "Gold Shield" (sample provided by Drew - thanks!) is considerably more proof against washing out.  In fact it is used by hospitals to sterilize and keep sterile their bedding, even tho it is frequently washed.

I call this experiment concluded, and a success.  I am going to treat the other tread plate, and our bare teak rub strakes, with Gold Shield.

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