Solar requirements and cost - 38 ft yacht

[billcole]

I made up a goalpost-like support from straight 25mm tube and bimini fittings plus a few bits of iroko. It's clamped to the pushpit with u-bolts.
The boat's out in Greece, so I can't post a photo, but it's like a Greek letter pi, with the uprights clamped to the pushpit, and (for stiffness and strength) the joints of the pi braced across at each side to the bimini with two tubes about 600mm long. The horizontal of the pi has four pieces of iroko with 25mm holes drilled in the middle and threaded on to it at right angles and roughly evenly spaced out, with two more tubes threaded through the ends of those, so I have three parallel tubes forming the top of the arch, which can be pivoted about the middle of the three to follow the sun (in one axis only).
The solar panels (4 x 25watt and 1x50watt ) are clamped to the "shelf" formed by these three tubes, and two 6mm lines, one from each of the outer tubes, are tied off to the pushpit to hold the three tubes at the chosen angle to best face the sun. I usually leave the panels horizontal for most of the day, but can improve the power generated by tilting them to face more east or west as necessary nearer to dawn or dusk .

 

[Crisby]

We have a similar arrangement on our M42, installed by the previous owner, 2x90w solar plus wind gen. seems pretty robust although I would be reluctant to use the davits supplied with it as it is all 25mm.

View attachment 75678

Chris

 

[neil1967]

DIY arch on Moody 376 here in Portugal cost me around €400 for steel and helper's labour. quoted €2,000 for professional one, it's also used as davits. Biggest problem was finding someone to bend 40mm tube. Just uprating our solar from 200w to 320w (2 x 160w) from Photonicuniverse, roughly £1/watt for Chinese made, German a fair bit dearer. https://www.photonicuniverse.com/

Graham, did you get the parts in Portugal, and if so where - I'm based in Lisbon. Any photos? Thanks, Neil

 

[Graham376]

Graham, did you get the parts in Portugal, and if so where - I'm based in Lisbon. Any photos? Thanks, Neil

We have a good stainless steel stockholder near Faro so got everything from there. No contacts in Lisbon area but if you visit the Nautical Club or chandlers at Belem, you may be pointed in the right direction.

 

[Pavalijo]

Hi Pavalijo,
Do you have a picture of your arch you could share with me please? Helpful to visualise the design.
Thanks

Hi MS, if you PM me your e mail I can send a few photos over - none taken with the intention of showing off the arch design but may assist!
Paul

 

[nortada]

Hi MS, if you PM me your e mail I can send a few photos over - none taken with the intention of showing off the arch design but may assist!
Paul

Likewise, got our panel arch made locally in 2004 in Logos from our drawings. It has proved very successful.

Should you wish it, I will photograph the arch and if I can find the drawings, I will copy them and email to you.

The arch is high enough to allow a 6ft 3in son returning from the bar to walk back on board with out braining himself!

One thing we did was to duplicate all the masthead aerials and the steaming nav lights on the arch so if we lose the mast..........!

 

[tiempo]

I bought my solar panels from these guys. Amazing prices and good service.

https://www.ev-power.eu/Solar-Panels/?cur=1

 

[Kelpie]

I bought my solar panels from these guys. Amazing prices and good service.

https://www.ev-power.eu/Solar-Panels/?cur=1

Thanks for the link.
The panels all appear to be high voltage types (nominal 30v), so if I understand correctly that means you will need to use a MPPT charge controller with them.

 

[tiempo]

I also bought an MPPT controller from the same guys and has worked really fine so far. With just two 80W panels I was self sufficient for weeks during the summer.

 

[Saguday]

We have a pair of 14-year old Kyocera 130W panels into a 500Ah house bank on our 38footer and in warmer climes they’ve made us almost completely self-sufficient. We’ve just spent the whole Easter weekend aboard on the Tamar with no engine only solar and battery, running fridge, laptops, phones, occasionally instruments and also charging an electric outboard motor from 12V no problem at all. I dispute wholeheartedly the idea that it’s not worth putting solar panels on in the UK, it’s nonsense. The two panels are simply mounted flat on two 1” SS crossbars on top of the Bimini, well out of the way with little shadowing. The dink is on davits and this is a much cheaper setup than an arch.

I’m finally thinking of upgrading the solar installation. Today I can do a 1-for-1 swap of our two panels and it would double our solar capacity from 260W to over 500W - if I could squeeze wider panels on I could make this 640-720W from two panels. Since the panels only cost about £220-300 each why would you not do this? MPPT controllers aren’t particularly expensive either. When we first put all this in in 2005 the panels were US$1000 each...!

I confess I want to upgrade only because I want to run an induction hob, microwave and a decent coffee machine off an invertor as I’m fed up faffing about with gas. Cheap solar panels and plenty of batteries make all of this possible, even in the UK.

 

[Baggywrinkle]

Built this last year.



I've got 300W of solar panels and 370Ah @ C20 of lead acid truck batteries, they rarely drop below 90% in the adriatic - they go from 100% to 90% overnight and are full again by lunch time sitting at anchor with fridge on 24/7, but more capacity is always better.

Reading the thread some of the decisions I made which might be helpful were:

MPPT over PWM is a very good idea, MPPT is more efficient than PWM. Also depending on shadows cast by mast, sails etc, investigate parallel panels (better when partially shaded) over series connection (better to achieve voltage to get MPPT going).

To match controller capacity to required charging current and also parallel/series connection you can use the calculator on the following Victron link - important is the start voltage to get the MPPT going which depends on voltage rating of panels and if they are wired in series or parallel and the max. voltage it can handle.

https://www.victronenergy.com/support-and-downloads/software#mppt-calculator-excel-sheet

I found the Victron HW and web site excellent, especially HW with bluetooth compatibility.

My energy requirement looks like this, I need about 1kWh a day from my solar panels, fridge is the monster ...



Cost was expensive but the freedom from shore-power and generator is priceless. I did consider a wind generator too, but in the med I don't need one - the solar works even on overcast days, and a brief run of the motor going in and out of anchorages is more than enough to top everything off. Best of all - solar is totally silent. :encouragement:

 

[siwhi]

Couple of considerations based on our experience:

1) The diameter of the tubing on our arch is on the small side so it flexes a bit, and I'm reluctant to use the integrated block and tackle davits which otherwise would be great. So go large on that. Aluminum would be preferable, I've seen some nice ones, but obviously trickier to integrate around the pushpit and stern with loads of stainless parts around. Larger diameter also means easier to feed to cabling.

2) think about any other stuff you want on the arch, eg kedge anchors holders, fishing rods, reels of polypropylene for stern to mooring, space for storing SUP boards, or fruit nets, various antennae, bbq, etc. Check the headroom with all the crap and cabling on it.

3) definitely go with integrated davits of you can. So much easier.

4) we have 2 x 330w domestic panels on our Moody 44. About $1 per watt. Like a power station. Means we only really use the batteries at night for the fridge or tv as during the day they are just not needed. So we can get away with less battery potential. With everything on when sailing, autopilot, plotter, fridge, tv (kids), etc on an overcast day we are still charging the batteries. Victron mppt definitely the way to go.

So that means we have an unreliable dodgy old generator for sale.

 

[Tim Good]

I've got a very expensive German branded panel and 2 other eBay specials which were £60 each for 120w. I can monitor each of them and there is naff all difference in output from the expensive and cheap ones. Build quality also seems comparable. I did however splash out on a nice Victron MPPT controller with Bluetooth connector. Well worth it but save your money and get some cheap rigid panels and a nice stainless frame built.

And don't mount your wind vane, radar or any other thing above them like so many people do.