Molteni
Well-Known Member
I'm sure the best Chinese ones are at least as good as German, but which ones?? There are so many available, from one third the price.
Solar panel on swinging mooring...thoughts
- Thread starter Matata
- Start date
Seajet
...
Unless one lives in the tropics or has the boat on an elaborate autopilot to keep pointing into the sun, all this worry of boom shadow is unfounded.
vyv_cox
Well-Known Member
In Greece we find our 130 W panels to be far more efficient at anchor than in a berth.
ghostlymoron
Well-Known Member
Any idea why this is so, Vyv? I would have thought it depends on the orientation of the berth.
Molteni
Well-Known Member
Shade maybe?
vyv_cox
Well-Known Member
Yes, I believe so. In port the panels are in shadow for long periods, from masts and rigging of other boats and with some orientations from our radar scanner.
Mistroma
Well-Known Member
Only if you want to spend about 10 times more money for similar average daily output during the summer months (or are only interested in the winter months).
Last edited:
Mistroma
Well-Known Member
Output is actually pretty good most of the time. I have 3 panels under the boom and get usually reasonably close to predicted Ah/day for a given location and month.
Overcast days actually present less of a challenge. The diffuse light means that there's often little or no discernable shadow on the panels. Lower output obviously but slightly offset by lack of shadow.
No point in anything other than mounting them flat when at anchor in most situations. I did benefit once in the Guadiana because wind and current were predictable. I found that output was much better with panels to one side and boom hauled out on other side. The boat usually rotated reasonably well in time with the sun's progress. Not ideal but better than leaving the panels and boom centered. However, that was pretty unusual.
coopec
N/A
No one has convinced me this is not the way to go. A couple of small tracking panels over the transom would be ideal.
https://www.youtube.com/watch?v=TvbjClm6fdg
This article in Practical Boating (which I have yet to fully read) seems excellent. I now know why some cells lose all their power when shaded and some only lose 10%
https://www.pbo.co.uk/expert-advice/solar-panels-everything-you-need-to-know-24455
https://www.youtube.com/watch?v=TvbjClm6fdg
This article in Practical Boating (which I have yet to fully read) seems excellent. I now know why some cells lose all their power when shaded and some only lose 10%
https://www.pbo.co.uk/expert-advice/solar-panels-everything-you-need-to-know-24455
Last edited:
Seajet
...
And unless the chap in the video is 4" tall, no one will convince me such a system is suitable for most boats ! 
coopec
N/A
And unless the chap in the video is 4" tall, no one will convince me such a system is suitable for most boats !
Of course I wasn't suggesting that! Geeeez!!
But I'm wondering about one of these? They come in 12V/24V and they are not too costly.
I don't think they'd be any good on a mooring though as they are only a single axis. (Mind you with two of them you could make a dual axis. It would be a bit sad if the tracking devices used more power to track than the system produced!)
https://www.ebay.com.au/itm/Complet...003764?hash=item2ee38a8d34:g:4RUAAOSw5cNYSAM7
Last edited:
Matata
Well-Known Member
thanks guys...thats helped a lot. I think ill set it up horizontal...with a semi flex 40w /50w panel...and dump any excess juice... we have two 100 amp hr batteries...one engine/one domestic.. we have very little led technology...still old school. We have auto helm / prob draws 2 amps/ and cabin lights/ radio etc. Ta Nik
ghostlymoron
Well-Known Member
If you're serious about power management, the first thing you should do is change all your lamps for LEDs. They're available in all shapes and sizes and for a modest outlay really will save you some power. I prefer warm white for internal lighting. I didn't bother changing the lamps in my low level nav lights and steamer as I only use them when the motors on but will probably do so when the old ones expire. I used Boatlamps for mine, not the cheapest but good quality and service.
Mistroma
Well-Known Member
I seem to remember producing some figures for a friend who was thinking of installing a tracking system at his home. I think panels at optimum slope gave about 58% more kWh annually than ones flat on the ground but 2-axis tracking was only about 3% better than fixed.
Not the whole story of course. Biggest gains from tracking and optimum slope were outside mid-summer months.
e.g. Optimum slope panels in June were 36% better than panels lying flat on ground and full tracking gave about 40%. By December the figures were 120% better and 140% respectively.
Unfortunately, fixed angled panels don't work well at anchor and probably worse than flat panels. Full tracking is more complicated and you won't get full benefit because of shading from mast and rigging. My rough guess was that 25% improvement should be possible but you'd get a fair amount from manually tilting panels (lot of hassle though
).
Seajet
...
I understand the desire to have ( sensible size ) tracking panels, but I don't think them viable - they'd probably want a prime position on the boat, and the mechanism is begging to go wrong.
I think a flat panel on the garage is fine for weekend & summer cruise needs, mine keeps the battery topped up and the boat has a lot of systems - I just keep an eye on the battery condition meters.
Something I want to add though - the makers of semi-flexible panels say the slightly ridged finish is ' non slip ' - well I'd like to see what they call slippery !
My panels have both had the friction co-efficient of teflon on ice.
If it weren't for this we could have lots more panels, and I reckon that the way to go, rather like the latest Hugo Boss - loads of fixed basically horizontal panels.
) tracking panels, but I don't think them viable - they'd probably want a prime position on the boat, and the mechanism is begging to go wrong.I think a flat panel on the garage is fine for weekend & summer cruise needs, mine keeps the battery topped up and the boat has a lot of systems - I just keep an eye on the battery condition meters.
Something I want to add though - the makers of semi-flexible panels say the slightly ridged finish is ' non slip ' - well I'd like to see what they call slippery !
My panels have both had the friction co-efficient of teflon on ice.
If it weren't for this we could have lots more panels, and I reckon that the way to go, rather like the latest Hugo Boss - loads of fixed basically horizontal panels.
JumbleDuck
Well-Known Member
+lots. Changing all my bulbs to LEDs vastly reduced my energy needs and was probably the best modification I have made to the boat. Boatlamps here as well.
coopec
N/A
My rough guess was that 25% improvement should be possible but you'd get a fair amount from manually tilting panels (lot of hassle though
AND
Originall posted by Seajet
[QUOTE I understand the desire to have ( sensible size) tracking panels, but I don't think them viable - they'd probably want a prime position on the boat, and the mechanism is begging to go wrong[/I].]
Mistrona the figure the experts have arrived at is a 30% gain in output by having them trackable. and I agree with Seajet that it is something more to go wrong.
My yacht is a ketch so there will be shadows from the main and mizzen sails. I think the only viable option is to mount a couple of smallish panels over the transom. (I note other ketch owners have done that) Maybe the best option is to mount them flat but have the ability of manually tracking the sun (say) X 3 times a day if I wanted to do..
But the other day I put in a ridiculous offer on eBay for a sun tracking controller (listed at $42?) and this morning it was knocked down to me for $17.50. I guess I've got plenty to do before I have to decide the way to go.
NOTE
I just checked to see what others were paying on eBay for these controllers and some bought for as little as $4 or $5. Never mind...... The "actuator" sells for around $80 so I suppose that is where they make their money.
Last edited:
ghostlymoron
Well-Known Member
If you have an adjustable mount, manually operated and forget to move it from evening to morning position, you'll probably lose more than you gained in the previous week. Surely a better bet is just to increase your panel area by say 25%.
Stemar
Well-Known Member
I'm a great believer in KISS. Yes, mounting panels flat is less efficient than tracking, but my 40w of panels keep up with my needs at anchor during the summer (LED lights & no fridge) and they keep the batteries charged during the winter, putting back over the week what I use during a weekend's maintenance, so all the extra I'd get from doing it "properly" would be wasted anyway. It'd be nice to have enough to run a cold box, but mine is a Peltier effect job that draws stupid power. It might be worth upgrading panels and box if I spent weeks on board, but for a few days at a time, I can struggle through without ice in my G&T
It was 10 years ago I did the research but, since the only practical place for panels was on the hatch garage, forward of the sprayhood, my best option was two rigid 20w panels wired in parallel to a two battery controller. When one's shaded by the boom, the other's in the sun.
It was 10 years ago I did the research but, since the only practical place for panels was on the hatch garage, forward of the sprayhood, my best option was two rigid 20w panels wired in parallel to a two battery controller. When one's shaded by the boom, the other's in the sun.
[70521]
Well-Known Member
How long are you leaving the boat between uses? When on a swing mooring we could leave the boat for upto six weeks and still have both banks of batteries on full charge without any solar panels.
I currently have a tiny solar panel for use when we are at anchor to replace the power used by the LED lights at night.
+1 for Boatlamps
I currently have a tiny solar panel for use when we are at anchor to replace the power used by the LED lights at night.
+1 for Boatlamps