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Old 21-03-2013, 04:45   #31
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Re: Tilting solar panels

WOW you guys are mounting some big panels. I was getting by with 80w total giving me about 5 amps max.

With that much capacity in the tropics probably just bolt them down and be done with it. You can always add a tilting mechanism later if you need it.

If you were to hinge it make the hinges on the outside as diagram 1 to maximize the unshaded panels power. The down-sun side will get shaded by boom, mast and backstay at various times.

Saying that I don't have any experience with that sized bank or solar in the tropics.
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Old 21-03-2013, 04:49   #32
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Re: Tilting solar panels

Hi Gord, that is an interesting guideline.
Since I am between 5 and 10 degrees from the equator not sure how to apply the summer and winter adjustment

Used this tool to try and figure out if there is a major seasonal shift given the dynamics of a boat installation
Sustainable By Design :: sunangle
(I used North 8° and Long W 116° as my guideline)… just confused me even more

So my question remains whether it is worth adding the complexity of a tilting mechanism to squeeze out a bit more in the early and late daylight hours
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Old 21-03-2013, 05:19   #33
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Re: Tilting solar panels

I played with the Position part of the tool Sustainable By Design :: sunposition to identify if any significant seasonal changes… did not find one at my latitude

But it does show altitude angles in the fringe daylight periods, so is it worth tilting for those periods?
Azimuth is not important on a boat

SunPosition output complete
Latitude is 8 degrees north
Longitude is 116 degrees west
Time zone offset from GMT is -8 hours
Zero azimuth is south
Output angle units are degrees

date time altitude azimuth
March 30
3/30 06:00 3.41 -93.52
3/30 07:00 18.26 -91.57
3/30 08:00 33.12 -89.56
3/30 09:00 47.97 -87.11
3/30 10:00 62.78 -83.21
3/30 11:00 77.35 -72.47
3/30 12:00 85.11 36.51
3/30 13:00 71.76 78.63
3/30 14:00 57.04 85.16
3/30 15:00 42.21 88.29
3/30 16:00 27.35 90.52
3/30 17:00 12.51 92.49
3/30 18:00 -2.32 94.53

September 29
9/29 06:00 6.01 -86.51
9/29 07:00 20.81 -84.10
9/29 08:00 35.54 -80.94
9/29 09:00 50.10 -76.06
9/29 10:00 64.21 -66.50
9/29 11:00 76.33 -38.90
9/29 12:00 77.51 31.32
9/29 13:00 66.06 64.25
9/29 14:00 52.07 75.01
9/29 15:00 37.55 80.26
9/29 16:00 22.83 83.57
9/29 17:00 8.04 86.02
9/29 18:00 -6.80 88.12
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Old 21-03-2013, 05:26   #34
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Re: Tilting solar panels

Quote:
Originally Posted by Snowpetrel View Post
....
If you were to hinge it make the hinges on the outside as diagram 1 to maximize the unshaded panels power. The down-sun side will get shaded by boom, mast and backstay at various times.

Saying that I don't have any experience with that sized bank or solar in the tropics.
Those were my same thoughts. On my schooner, the aft boom is just a reaching sail, so my boom travel is very limited.

It will be easier if I make it hinged now if majority advice is that it is worth the trouble for early morning efficiency
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Old 25-03-2013, 01:36   #35
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Re: Tilting solar panels

Sun seeker is useful little, free program for the iPad (and probably android)

It will overlay your position, with the suns path on a google earth map. It also lists the suns current elevation etc.
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Old 29-03-2013, 05:15   #36
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Re: Tilting solar panels

Try this site: Solar Angle Calculator | Solar Panel Angle Calculator
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Old 29-03-2013, 21:01   #37
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Re: Tilting solar panels

We've had four 125 watt panels on a fixed mount over the cockpit since 1999. Four years in Western Mexico ( North 27 to 17 degrees ) at anchor almost the entire time. Never once needed to generate any electricity other that what the panels provided. We were electrical usage hogs: watermaker, lots of HAM radio usage, big computer, cold refrigerator, movies on the TV every night.

We could make 17 gph water, run the reefer, and still trickle charge the batteries with our fixed mount panels in mid-winter at 24 N.

My brother had full adjustable panels on his Tartan 42 in Mexico - after six months he quit adjusting them. He did notice a significant drop in power generated but still produced way more than he ever needed.

Same result for another friend who has been to Western Mexico three times on his Norseman 447 and on to Florida one time. He built fully adjustable panels in 2000 and quit adjusting them in 2002. He is still cruising and never bothers adjusting them.

Adjustments help a lot but 500 watts of nominal panel power is plenty for a fix mount in the tropics for most any application.

And, realistically - when cruising we were seldom on the boat during the time we would be adjusting the panels - mid-morning or mid-afternoon. We were usually out for a run, hike, snorkeling, fishing, visiting friends so who would do the adjustments?

NO shadows is far more important than adjustments on a practical day to day usage.

Just my opinion based on 14 years of usage.
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Old 31-03-2013, 14:21   #38
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Re: Tilting solar panels

For us having a tilting panel is fantastic & a definite must have.

We have one Sunpower E20 327W panel on a tilting mount over the davits. It works well here in North Queensland as most times when we need to tilt (morning & afternoon) the stern is facing the sun due to the predominantly easterly day breezes and westerly land breeze that kicks in most nights/mornings.

To illustrate, this morning I tilted the panel at 6.30am as the sun rose over the island behind me & I was getting 9.4amps into the batteries according to both the Tristar MPPT & Enerdrive battery monitor. Now at 7.15am I am already getting 14.0amps.

So when you are keeping it simple, tilting the panels makes a world of difference! Besides in our case it wasn't much extra to make the panel tilting as opposed to fixed over the davits .... the only difference being the telescoping front struts. For the cost of a little time in tilting against the cost of an an extra panel etc etc etc ... the little time taken to tend the panel a few times a day pays for itself many fold.

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Old 11-03-2018, 17:30   #39
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Re: Tilting solar panels

Quote:
Originally Posted by surfingminniwinni View Post
I used Atom Voyages design, showed a local metal fabricator and he made them up for us. I swear by this design, we never ran out of power.

Atom Voyages - Atom Solar Tracker Demonstration
First, sorry to revive an old thread, the market doesn't seem to have these even after years. I am planning something similar, either getting an Atom-clone fabricated or using this as a base:



I intend to use flex panels in a frame, maybe 2x200W: these combined would weigh less than a 200W rigid panel, the only worry is windage.
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Old 11-03-2018, 19:11   #40
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Re: Tilting solar panels

Every time I have seen someone come out and tilt his panels, his boat swings around at anchor, and the gains are gone. Flat is the best average, unless you're on a dock, but then you have shore power anyway.
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Old 11-03-2018, 19:59   #41
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Re: Tilting solar panels

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Originally Posted by sy_gilana View Post
Every time I have seen someone come out and tilt his panels, his boat swings around at anchor, and the gains are gone. Flat is the best average, unless you're on a dock, but then you have shore power anyway.
Thats a bit like saying everytime someone adjusts his sails the wind shifts and the gains are gone, beam reach is the best average... set and forget! Or buy a motorboat because sails are just too much hard work.
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Old 11-03-2018, 20:06   #42
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Re: Tilting solar panels

Anyone doing automatic tracking? I'm looking for 2 axis automatic tracking

Quote:
Originally Posted by GTom View Post
I intend to use flex panels in a frame, maybe 2x200W: these combined would weigh less than a 200W rigid panel, the only worry is windage.
If you put the hinge just after the center of balance, and use a weight, then strong winds will cause it to feather.

Quote:
Originally Posted by sy_gilana View Post
Flat is the best average, unless you're on a dock, but then you have shore power anyway.
Flat is lame in winter, and I've been to a dozen docks in the last few months, none had power.
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Old 11-03-2018, 21:17   #43
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Re: Tilting solar panels

For boats in high latitudes, tilting makes some sense, as it can cut reflection losses significantly. But it's also generally weaker, both for sailing & in storms. I'm an engineer, so very interested in efficiency, but Ocelot is a tropics boat, so efficiency gains would be minimal & I wanted the strength of rigid mounting. An auto-tracking setup would be very cool, but I haven't seen one that's very cheap.
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Old 11-03-2018, 22:10   #44
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Re: Tilting solar panels

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Originally Posted by Jon Hacking View Post
For boats in high latitudes, tilting makes some sense, as it can cut reflection losses significantly. But it's also generally weaker, both for sailing & in storms. I'm an engineer, so very interested in efficiency, but Ocelot is a tropics boat, so efficiency gains would be minimal & I wanted the strength of rigid mounting. An auto-tracking setup would be very cool, but I haven't seen one that's very cheap.
Tidal streams are usually strong here, thus on a swinging mooring/at anchor you only need one azimuth set for flood another for ebb. Easy to set if you are around (=consume electricity...), unncecessary when away for a longer period (fride empty, only consumer is your anchor light & battery self discharge).

Quote:
Originally Posted by boat_alexandra View Post
If you put the hinge just after the center of balance, and use a weight, then strong winds will cause it to feather.
That's my main worry with lightweight panels, maybe I should find a weight compromise with a heavier stainless frame, that would still allow 400W worth of panels but be somewhat more stable.

Quote:
Flat is lame in winter, and I've been to a dozen docks in the last few months, none had power.
That's my case: sailing in the UK (going more and more North) and my budget berth has no electricity.

As for windage: I dont see a m2 (equivalent of ~250W) worth of space on the boat, where I could place the panels without partial shading. I either need an arch or a pole - both contribute to windage, pole can be fully adjustable arch not.
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