Solar rethink

This post is a bit meandering, as I have toyed with various possibilities:

1) Replace the thin flexible panels on the canvas shades.
2) Replace the solid glass panels over the davits.

If you want to 'cut to the chase', I have made a decision to order two thin flexible 180 watt panels made by eArche, and distributed by Solar 4 RVs. We will keep the old BP3125s over the davits, and their frames will not need to be changed.

                                                                                   

A very kind Seawind 1160 owner gave us his surplus solid Targa infills. These are the panels to take the place of the canvas shades over the cockpit. The canvas shades are a bit of a death-trap. Unwary crew can promenade down the solid walkway beside the boom, and if they haven't ensured that the boom is tethered securely, an unexpected gust of wind can cause the boom to sweep them off the walkway like a windscreen wiper sweeping a bug off a windscreen. Said crew then steps on the canvas shade and falls into the cockpit, breaking things.

So we were delighted to be given these solid infills.

Meanwhile the 120 watt SolarPlex thin flexible solar panels that we installed by zipping them onto the canvas have deteriorated. They were new in mid 2014, so they are now 3½ years old. They have gone all milky and opaque. 

BP3125 panels over the davits. SolarPlex SR120 watt thin panels zipped into the canvas.

It may be that all flexi-panels are not the same. I found this NZ supplier who distinguishes the different models. SolarPlex is Chinese, and uses PET as the plastic coating. SolbianFlex is Italian, a lot more expensive, and uses a 'high-tech polymer'. A discussion on PET degradation on the Cruiser's Forum here.

We bought ours from Solar Future, a company that appears to have gone broke. Their website is visible on the Internet Archive. They sold the three ranges: SL, SP and SR. Ours are the cheaper Chinese SR Solarplex brand.

Our setup is very similar to Alan Hunter's Talisker. Alan has Solbianflex panels, (although they look identical to our Solarplex panels). He has larger Enerdrive 200 watt panels over the davits.

So the question I want to explore is how to reform our solar power. On the Seawind FaceBook page a few others have expressed an interest in following the topic.

Nimrod was launched in 2008. The BP3125 panels were fitted then. They produce 125 watts each. The original solar regulator was a Steca Solarix PRS 2020, which used the PWM system and was good for 20 amps. When we were struck by lightning in 2013, I replaced it with a Morningstar Tristar TS-MPPT-60.  If you haven't understood the importance of MPPT, I suggest you check it out. It made a huge difference to us when we changed from PWM to MPPT, as I discussed in an earlier blog. In addition, if you want to join panels of different voltage together in series, it is essential that you have a MPPT controller.

So. What developments have occurred in the last 9 years?

Efficiency

A massive amount of research has been going on. The efficiency is the ratio of the solar energy hitting the panel and the electrical energy passing out of the wires.

My BP3125s have an efficiency of 12.3%. Modern LG NeON R 360 panels have 20.8%!

Size

Panel	Length mm	Width mm
LG NeON 330W	1686	1016
Irex IR205M-72	1580	808
Enerdrive 200W	1580	800
BP3125	1510	674

If one put some LG NeON 330W panels over the davits, in place of the BP3125s, they would be 176mm longer, and 342mm wider. Would that matter?

Compared to Talisker's they would be 106mm (4") longer and 216mm (8½") wider.

I think that would be acceptable. Opinions from others welcome.

Panel	Watts	Weight kg
LG NeON 330W	330	18.0
Irex IR205M-72	205	15.5
Enerdrive 200W	200	15.3
BP3125	125	12.0

Panel	Price	Voc volts
LG NeON 330W	$365	40.9
Irex IR205M-72	?	45.4
Enerdrive 200W	$359	43.7
BP3125	Out of stock	22.1

If you create a sub-array of two or more in series, it is important that the sum of the Voc figures is below the limit on the solar controller. The Morningstar Tristar TS-MPPT-60 can take 150 volts. Thus a single string of four panels in series would be risky, but two strings of two panels in series, with the strings connected in parallel should be fine.

Panel	Impp amps	Efficiency
LG NeON 330W	9.8	19.3%
Irex IR205M-72	5.62	16.1%
Enerdrive 200W	5.37	?
BP3125	7.23	12.3%

The issue with Immp is that if you buddy up two panels in series with widely differing ampage capacities, it may cause a restriction in the current flow and a heating of the smaller cells in the series. This may reduce the system performance and /or cause premature aging of the small modules.

I asked MorningStar tech support about possibly pairing some LH NeONs with my BP3125s. He said: 'Although the rated current (Imp) of the two modules is slightly different (7.23a and 9.8a), the current mismatch is much less than your present configuration. I do not expect much (if any) current limiting due to this mismatch, in real-life performance.'

Meanwhile, Mike Rees from Seawind in Vietnam tells me: "We are still in the process of getting the panels in but we have worked out a way to fit 1.12 Kw if required. At this stage we are looking to have a 350 Watt panels either side of the tri-fold door line above the cockpit. 820mm W x 2600mm L x 2.5mm Depth. That's 700 Watts on the roof + the standard 2 x 210 Watts above the davits. This configuration would also fit on the 1160."

The ones he has been considering are made by DAS Energy in Austria. The panels look very nice, with  ETFE-Film on the front, which should be more resilient than the PET surface layer that we had on the SolarPlex SR120s. 

I note that the new ones being tried in Vietnam are 2600mm long. That is longer than the solid infills which are 1900mm long. In other words, the thin flexi panels would pass over a join in an older 1160 being fitted with solid infills, which might make for an irregular connection to the roof.

When I approached the decision to buy the DAS Energy panels I was put off by the high cost of transport. Two 200w panels delivered would have cost about $2,000, plus possible tax.

2) Replace the solid glass 125 watt panels with larger 200 watt panels.

Alan Hunter of Talisker strengthened the frame that supports the solar panels when he increased the size of his solar panels over his davits.

Compared to BP3125s

If I were to put on the LG NeON 330w panels, the overlap would be significant. I'm inclined to go with an extension to the frame using welded stainless steel. 

A stainless strut to the corner of the panel

Strut connecting to corner of Talisker's panel

Compared to Talisker's Enerdrive 200W.

Important to have an extended mainsheet deflector.

Matt's dream

We have now been holed up in Keppel Bay Marina at Rosslyn Bay near Yeppoon for about a week, while a strong south-east gale takes its time to get out of our way.

We have learned to avoid deadlines when cruising; if pressed to be somewhere at a certain time, whether because of a social or other commitment, Murphy's Law throws in a breakage or weather which can turn the pleasure of cruising into a dangerous or stressful activity. Instead, let's take our time, chill, and enjoy going with the flow.

Marinas can be interesting places. We meet all sorts of people from different walks of life.

Our next door neighbour here is Matt, fiftyish, a big man with hair down his shoulders, and the trace of a South African accent. He looks like a bikie. But friendly as, and a heart of gold. He lives in Vanuatu and runs a commercial diving business,  and also services cruise ships.

He was standing on an absolutely huge catamaran. Massive (25 metres), messy, and clearly a big job to clean up and get seaworthy. It has gradually been decaying in Yeppoon over several years, with the owner unable to pay the import duties or realistic costs of maintenance. This massive old super-yacht eventually sold for about the price of a Seawind 1160 like ours! Only to someone with the chutzpah and skills to take on a huge project. 

Matt is such a man.

I bought it yesterday!

The galley

The captain's boudoir

Andy, the sparky. Plenty to do.

South for the summer

We decided to bring Nimrod south to Raby Bay in Moreton Bay for the summer (cyclone-prone) months. We left Abell Point Marina on Saturday October 28th and enjoyed a catch-up with some friends in Turtle Bay on the south coast of Whitsunday Island.  

Then we set off south, taking advantage of the gentle northerly wind to put up the kite and get down to Keswick Island on Sunday and Middle Percy Island on the Monday. We caught a Big-eye tuna; magnificent sashimi!

Red cliffs in Dolphin Bay, Middle Percy Island, at sunrise

Next day, another kite run down to Shoalwater Bay. There was a military exercise on, but the affected area left us room to go on the west side of Townshend Island and sneak up Canoe Passage between Townshend and Leicester Islands.

For those who don't know the procedure, the best way is to check the 'Notices to Mariners' on the 'Capricorn Coast—outside pilotage areas' website. On this occasion Notice '431 T of 2017' applied, but showed a chart indicating where we could go.

We could hear some distant gunfire, and some thunder. Crab pots were put out, but three were broken, one badly, presumably by a crocodile.

Rumbling noises in the west

The forecast was for an inconvenient Southeasterly, building to 25 knots. We decided to motor round Townshend Island and spend the Wednesday night in Strong Tide Passage near the Triangular Islands.

Thursday a short hop around the coast to our favourite hide-away; Island Head Creek. Beautiful, deserted, and a good place to practice using the Mavic Pro drone.

Then, although the wind direction was adverse, the sea was pretty quiet, so we decided to press on and motor-sail to North Keppel Island, where there are some lovely bush-walks.

Mangrove roots

Grass-tree stump

Sometimes cruising is easy; sometimes things go wrong, or the weather turns against you. Recently we have had a few technical challenges: a pesky flashing light and annoying alarm on the engine panel. A dodgy freezer. An oil leak from the genset.

All of these have been overcome successfully, but now we face about a week of strong SE winds making further progress south difficult.

We will sit the gale out in Rosslyn Bay Marina near Yeppoon and enjoy a bit of land time.

Wind building

View from Bluff Point

Rosslyn Bay

Gladstone ferries at dawn