Solar Panels 32' Sloop

[barnakiel]

Hey,



Solbian SP52Q 52 watts $529.00 --- $/watt = $10.17

Q: So now Solbian makes their own panels? I thought they used to buy stuff in China and rebrand it to resell at a margin? 52 Watts at 529$ is errr a HUGE RIP OFF ???

compare:
https://www.svb24.com/en/spr-e-flex-...nel-170-w.html

(not linked, and not vested but did buy these before)

What brands of panels do you use and how often do you have to replace them? Which ones do you like the most? Do you use any flex panels?

Plain vanilla panels in alloy frame. If the boat is big enough, we buy 24V or 48V panels from local solar wholesale. These come at below 1$ / W in large size and about 1.5$ / W when we are forced to use 12V panels smaller than 150W each.

Life expectancy: a Siemens unit here is 15 y.o and delivers about 90% of rated output. I doubt China made ones will last 15 years @ 90%. But they may.

big boat no space limitations, something like:
https://www.damiasolar.com/productos...lina_da0109_16

small boat, space at premium:
https://www.damiasolar.com/productos...lina_da0109_16

I have also used 48V panels.

The above are generic examples and I am not vested.

I use Victron mppt / bluetooth regulators. Because I can buy these from a shop 200 yards from my office (=my boat). Small one is about 90USD and can handle 75V / 15A which is enough in any small boat. It has a shunt inside and monitoring and programming is done via any Android smartphone.

When the owner is more flush with $$ we may opt for very nice back-linked "black" monocrystalline units. We buy them from SVB. These are about USD 3 / W but have the highest efficiency per sq ft. Small footprint, prime quality, medium $$ / W.

Also I was considering making a very light frame of carbon fiber tube for the bimini panels, but that is too expensive.

Well, buy prefab carbon pipes or use old windsurfing carbon masts - cost nil $$ - if you have surfer friends! YET - I would not build anything in carbon as it is highly corrosive with alloy (panel frame) and steel (bolts,nuts) + salt water.

... attaching the flex panel () with Silkaflex 252.

Mind panels like to have an air gap to keep them cooler.

Also read Webb Chiles blog where he says about flexi panles. These have much higher failure rate and most of the time come more expensive up front (compared to rigid frames)

I too have seen a 'client' of mine (=a sailing friend, but he paid for my advice) crash a USD 700 flexi panel when trying to bend his new unit to match the roof of his dodger. I said it was more than that 3% given by the manufacturer, he insisted it was OK. I stepped back, he pressed the panel ... you know. 700 USD. 700 USD.

After that most unfortunate (but previsible) accident I searched the web and found him a different brand. This time I did the installation over what clearly is about 5% bend. The boat is now in the Pacific and the panels work as advertised. Note this make is said to accept up to 30% bending.

I want to say there are flexible panels and then there are flexible panels and you want to read the fine print. Some makes are known to be 'delicate' and less than perfectly watertight.

DREAMING: yes, in my boldest dreams my boat carries the Mini Transat styled ultralight frameless panels on the dodger, on both handrails and on the stern, attached with cable ties.

But then I wake up and I look at our rigid panels hanging from our split backstays and I look at the monitor and discover we are at 100% and it is not 14:00 sun time yet. Bingo. (Just that those uldb panels are so bloody light, and weight is so bloody important in a small boat!)

To sum up:

- I use the biggest panels, highest voltage I can fit, (1 to 1.5 $ per W)
- I use mppt plain vanilla regulators (now: Victron with bluetooth),
- I avoid building fancy frames and use existing infrastructure, (stays, dodgers)
- I have found regular ss biminis strong enough for any panel,
- dedicated arches and frames are $$/$$$ - the ss welder makes way more money than me ! (no envy, but I should have studied welding instead !!!)

My own installation is about USD 300 worth in materials (150W,regulator,cables). No frame, spectra harness on backstays. My boat is 26'. The biggest plant I have built is 3500 Watt (40' cat).

I use plain car batteries in my own boat. I specify regular 'trucking' AGM batteries when ordering stuff for solar installs elsewhere. This is because my own boat and sailing style are low footprint while regular cruisers have extremely high power footprints (fridges,aircon,AP,4K,sat TV,you name it).


Cheers,
b.

[rgleason]

B.
It's clear you know far more than I do about this, so I have a few more questions if you don't mind. As since you're familiar with small boats, I think you understand the issues.

With my locations at bimini & dodger and companionway cover there will inevitably be shading issues (backstay mounted radar, boom and main sail).

I understand that polycrystalline panels are better than monocrystalline panels are better for shaded conditions. Is that true? I understand that monocrystalline is better in ambiant/low light, but I can't figure out what these flex panels are mono or poly?

Also I understand that it is best to wire all panels (separate panel on port and starboard) back to separate controllers, and that the second best thing to do is too wire them in parallel, with blocking diodes in case one gets shaded. (I understand most panels built now have internal blocking diodes for the internal circuitry).
Is this true? I admit that getting separate small genasun mppt controllers will be a significant cost. How much would I loose by going to a single bigger mppt controller and wire everything in parallel?

Finally, my Dodger is so small that the most I can fit on one side is 50amp panels, and these don't have enough room for 36 cells to get up to 18v (36 x .5) . In fact they have 16 cells x .5v = 8v. Since I have two of these port and starboard (one has a high likelihood of being in shadow) they each need to be wired to a dedicated genasun mppt boost controller ($150) to output adequate voltage to the 12v batteries.

You've suggested using 24v panels in this location, I believe. The area is about 24" x 26" for each panel. I haven't found any 24v panels for that size, probably because there are not enough cells. If I were to find such a panel what are the advantages of 24v panels and how would you wire them up with a controller?

I believe the 160w Bimini locations (26" x 54" available space) could be 24v panels .

Thanks very much! I gather you actually install solar? Where may I ask?
Best
Rick


PS: I agree with you about the cost of frames etc. but I've looked into it and I think I can make some frames for flex panels that will be 1/2 the weight of the glass panels for not that much money or time. I will describe it in another post to get your thoughts.

[rgleason]

I just had an idea to reduce the number of controllers.

One side or the other is more likely to be in shade, so
Wire the bimini and dodger port side in parallel to an mppt controller and do the same to the starboard side to a different controller.

But I don't think that would really solve the low voltage problem with the dodger panel, so maybe they should be wired in series, even though that is not as good when parts of the panels are shaded... (but it is less likely when they are on the same side).

Later: Of course I could get two boost controllers and wire the port side in parallel and do the same for the starboard.


Even later: Actually I think wiring in series would be a bad idea because the dodger would drop the voltage of the other panel and it would be an overall loss I think, best to keep them in parallel. So this leads to a question. Do panels have to be identical to be put into parallel? I am thinking that that is the best thing to do, so maybe this is not a good idea at all.

[rgleason]

"For maximum output when connecting different panels together, connect panels with equal current outputs in series and connect panels with equal voltages in parallel. If neither the current outputs or the voltage outputs are close, don't bother hooking them together unless you can find a series/parallel combination that will yield a matching result. (ie: two 12 volt/5 amp panels in parallel then connected in series to a single 12 volt/10 amp panel)."


I'm now thinking that I might be better off getting two cheap mppt controllers for the bimini panels and two genasun boost for the smaller dodger panels.


This is really instructive:

https://solarpanelsvenue.com/mixing-solar-panels/

https://www.youtube.com/watch?v=P3YtBrymJdA

24 volt Panels are always cheaper due to the reduced cost of the wiring.
Save on the solar charge converter because at 24v it puts out double the amps.

12 volts VS. 24 volts for Off-grid Solar Power Systems

[rgleason]

Weight Cost
1.44 lbs $8.50 Frame Granger Alu 1/2" C

6.2 lbs $230.00 Solar PV Renogy Flex

3.7 lbs $60.00 Acrylic 8mm 2 wall
11.34 lb $298.50


Total weight is significantly less than the 25lbs of a similar wattage glass panel, saving 14 lbs/panel x 2 panels = 28 lbs which is equal to the weight of the outboard (wish I could find a good place for that towards the center of the boat).

Sikaflex252 used to secured PV and panel.
$298/160w = 1.86 $/w <--- Installed cost per watt, not including electrical.


See detail pdf

[rgleason]

Barnikiel wrote:

Solbian SP52Q 52 watts $529.00 --- $/watt = $10.17

Q: So now Solbian makes their own panels? I thought they used to buy stuff in China and rebrand it to resell at a margin? 52 Watts at 529$ is errr a HUGE RIP OFF ???

No they aren't making panels. These were from

https://www.coastalclimatecontrol.co...r/solbian.html

[barnakiel]

Hey R,


Yes. Shade is bad. Broad shade that shades part of a panel ( e.g. shade from a sail) annihilates output from this one BUT a shade of a SS 6 mm shroud one meter away has negligent effect. So this is OK to install where standing rigging shade falls. Also - objects far removed from the panel seem to be of little importance - on our boat the mast will cast shadow over both panels in the morning in the Caribbean (boat faces E and panels are behind the boat) - yet there is no significant loss of output - mind the mast is only 6 inch diameter and it is 16ft away.


Yes. Multi-crystal panels are said to be more efficient when partly shaded. Maybe because they tend to have very many smaller cells while the mono panel will have fewer bigger ones? I do not know. But I know that mono cells have prime output in full sun, so my foolosophy is to max out in full sun and then allow for periods when shade will degrade output to some extent. I would use multi crystal units without hesitation if I could not have mono crystal ones. Mind most if not all bendy units are in fact multi crystal ones.

I tend to avoid linking two 12V panels to make one 24V Cell WHEN I can get one 24V panel - costwise one big 24V panel comes less expensive that two equal 12V units. However, very often there is not enough space for one big 24 (or 48) unit and then I will join 12V units to build up voltage. Mppt regulators accpt V up to a point (our smallest unit takes up to 75V - 2 x 12V panel.)



Why I build up voltage (=I no longer feed mppt regulators with 12V even though most batt banks are 12V). Well, reading a bit into Victron manuals I found their mppt regulators have a fairly high kick in Volt point. Do not ask me how I found out ;-) The net result is you may want high Volts early to start charging early. And a 12V panel will NOT wake up a Victron mppt for a time in the morning. So I either use 24V panels or else join 12V panels to get V high almost as soon as the sun is up.


I want to kick in early because my batts are lowest early.



No. I do not use extra blocking diodes. I opened some boxes (junction boxes fitted below panels) and discovered there are diodes in the boxes. I also measured a panel in the dark and did not find significant resistance. Hence my assumption is the shaded one will not lock up juice from the active one. My assumption may be wrong, of course.


No. I would not use many regulators rather than one. Unless there is a very valid to do so. There is no harm, I think. But why do it? More regulators = more wires. Sure with only one regulator, do carry a spare (even if only a cheapo PWM model). And the people for whom I do solar work on their boats also carry one extra. It is much easier to swap regulators on a passage than unwire and wire panels to feed the batts directly - becuause you only can feed 12V panels into 12V batts. So if you wired the panels at 24V then you must unwire them before going hard direct and illegal (panel to batts, no reg). And you must keep eye on volt metter and disconnect the panels on time. But such things are emergencies.



By going higher Volts into an mppt reg you save money in regulators - because they are limited in A rating but will always accept at least 2 x 12 V panels joint into a 24V input! One regulator is cheaper tan two ...



Technically, your air channel pads for panels are fine. In fact, alloy would be the material as alloy is the regular heat sink material NOT ACRYLIC. But I still think this will work as long as there is some draft. However, extra acrylic pads will take from the weight saving potential. How much - depends on weight of the acrylic.


They goo is not structural silicone, it is structural polyurethane or similar glue. Yes, 5200FC or equivalent Sikaflex goo. Also any other home and depot good rated as exterior and structural (on alloy and whatever materials you join). Price at depot USD 5 per cartridge, price at chandlery USD 20 a cartridge, but it is the same stuff inside the sausage.



Doh. I am not a pro installer but I did a handful of installs and they all seem to deliver good amps and keep the owners happy. "My thing" is weather support and routing for adventurers (many of them in boats). But I need something to do when the sailors are not sailing and the climbers are not climbing, hence my tinkering with solar plants, programming and such likes.


I work and live in the Caribbean (mostly Martinique) and in Canary Islands (mostly Las Palmas). Now I am writing this from Canary Islands. Both places are prime solar spots. (5-6 sun / hours per day)



Basically, in a small boat:


- keep it simple, fewer elements if viable,
- use identical or very similar panels, if you use many panels,

- wire for at least 24V panels output - on 12 batts - if using mppt regulator,
- if you mix and add, mix and add same panels or very similar ones,


I find 100 W solar per 100 Ah battery is about the happy minimum (again: Caribbean and Canary Islands, Cabo Verde, etc.). More W is better. Stationary. If you make long ocean crossings, you want more W. Mind our boat is marginal - no fridges, no air con, no AP, no large blazing screens). This rate gets us as much Internet and laptop time as we want and unlimited LED light throughout the boat (heaps of it as I hate dark smelly boats). For at least one installation I used 6x the ratio. Yes, most cruisers use that much, and more (hence gensets).



If you can hand the panels so that they will angle towards the sun, DO SO. Big gains and zero extra cost.



Last but sure not least: FUSE. Mind the regulator to batt wires can be quite some copper. Fuse.


Well, my 2 cents. Looking forward to see what you have built and how well it delivers.


PS One more benefit of using very similar panels throughout - if you find you have shade / regulator / other challenges, it is so much easier to reconfigure identical units rather than units that are different in their V / A properties.


PS Buy panels with identical connector standard. This saves time, you are plug and play and waterproof all in one.


Cheers,
b.

[rgleason]

Barnakiel
Thank you for your guidance.

You may be right about polycrystaline panels. I don find polycrystaline flex but I could be wrong. So I am going with your suggestion to just use monocrystaline because it outputs more with sun is shining.

There is a problem with the 16 cell 50w panels for the small dodger, because the voltage is less (16x.5v=8v), Renogy and others like Solbian 50w panels have this problem. However Fly Solar Tech has a 50w panel with split cells 32 cells x .5.?? = 18v which solves this problem. Unfortunately there is no 24v panel of this size because it is not a large demand item. The bimini panels could be 24v.

I like Victron controllers, but it is good advice, saying they require high voltage to kick in, and you want early startup to start charging the nights use, so you parallel wire 24vdc same sized panels.

So with the Fly Solartech 50w panels at 18v, it is possible I believe, to wire all the panels in parallel using one Victron controller. Now I am considering if it would be worthwhile to have port and starboard controllers for each sides panels?

That is good news about the diodes.

Technically, your air channel pads for panels are fine. In fact, alloy would be the material as alloy is the regular heat sink material NOT ACRYLIC. But I still think this will work as long as there is some draft. However, extra acrylic pads will take from the weight saving potential. How much - depends on weight of the acrylic.

I looked into aluminum sheet 1/16", .032" and 1/8" and it all seemed pretty expensive, but a single sheet would have better cooling. I wonder if using a single sheet of acrylic under bimini panels would be better with respect to heat? Or should I just glue them at the edges and not have any additional support? Would that be better?

What do you use if anything to provide cooling under your panels, or do you seldom install flex?

BTW the panel as shown with 8mm 2wall clear polycarbonate panel would weigh 11 lbs as compared to the 25 lbs of a typical glass 160w.

Structural polyurethane is tough stuff. It may be hard to get up years later. You must work carefully.


I am going to attach some additional drawings showing some ideas for building the adjustable bimini panels. For glue down to the deck cover is anything needed underneath like the 8mm polycarbonate double wall to provide air flow?


So I am attaching the sketches.

[akopac]

We have 4 x 100w panels on davits on the stern pulpit rails. Probably one of the best investments we made was having rigid stainless tubing added to the stern pulpit extending to the gates. Really sturdy. Great for mounting anything on. The panels are removable. Took them off for a hurricane in El Salvador in a couple hours, however they do require a us standard socket wrench to remove to prevent theft. We do use them underway too. Haven’t had any issues with them in 15 years now. I fabricated the mounts from stainless, aluminum scrap, and king starboard. The whole davit assemblies could be unbolted if I were to sell the boat and want to take them off. You would really be surprised to find out how much more power you can get by directing them even just once a day. We generally point and leave them.

[rgleason]

akopac I really like your approach. The removable swing panels give you lots of flexibility and adjustments. It is a practical solution that augments solar output and allows you to remove them for storms.

Do you think this would work on a smaller boat that does not have the same freeboard? You say you deploy them while sailing. I am afraid we'd be dragging our panels through the water on the lee side sometimes. I guess you just don't have them winged out then.

This could be done in steps. First get the two panels and mount them on the stern pulpit rails. Then fabricate the swing gates and mount the panels there. Ideally these could be bifacing panels, taking reflections of the water.

I had been hoping to get some additional shade in the form of bimini panels, but I suppose you could even have both the rail mounted swing gates port and starboard and some bimini panels.

Thanks for posting the idea and the pictures.

[misfits]

Here's the picture of my friend's setup. It's a single 100 watt panel & it provides him with all the power he needs.
IMHO, you're making this more complicated than it needs to be. I would bag putting panels on the dodger & each side of the cabin top. They will be shaded most of the time. Just saying.

[misfits]

Pics of his setup

[Salty Possum]

Originally Posted by misfits

Pics of his setup

My 31 foot has two newer 100 watt panels on the Bimini. Often one or the other is partially shaded and I don’t think that I have ever seen more than 120 watts total output, which is more than enough for me.

It has an older Siemens panel in front of the dodger. It functions but actually adds nothing as it is nearly always largely shaded and utterly pointless as far as I can tell. I am considering just taking it off and mounting fuel cans there. It would be nice to be able to mount it where I can adjust it to the sun for extra power when I need it.

[rgleason]

Originally Posted by misfits

Here's the picture of my friend's setup. It's a single 100 watt panel & it provides him with all the power he needs.
IMHO, you're making this more complicated than it needs to be. I would bag putting panels on the dodger & each side of the cabin top. They will be shaded most of the time. Just saying.

Well Misfits, complicated is the direction I often go it is just genetic I guess, but I work hard to simplify and eventually I get there and know why I got there at least, even though it may not be exactly what I was hoping for.

Your friend's setup is great and nice and simple. Get the biggest damn panel you can find and mount it off the stern. Done! Looks good on his boat.

• But you see I have to think about it. Normally I lift the OB from the dingy at the stern with one hand direct onto the OB bracket on the stern railing. Then hoist myself aboard with one foot on the toerail and one hand on the backstay. It is quite convenient.
• Then there is the nature of the boat, short WL footprint, Ted Hood CCA design that does not like unnecessary weight at the two ends, and I like to sail it effectively.
  • I'd like to move the Danforth & Rode to the cabintop which would move about 25 lbs from the lazerette. This should be done.
  • I'd like to stow my OB towards the center of the boat but have not figured out how to do that because the stern location is so convenient. The OB weighs 28 lbs.
  • I'd like to keep the panels light and adjustible angle if possible.
• Ideally I would like about 300 to 350 watts of solar. It does not sound like the bimini, dodger and companionway cover are very effective locations due to shade.(Thank you Salty Possum!) This has been an issue I've been concerned about and have not managed to determine how much of a penalty these locations have.
• I do want more shade in the cockpit or we will end up looking like prunes!
• We've had a 14watt panel mounted on the dodger for years now to keep the masthead light on and to recharge and top off the FLA T105 (215ah). It does seem to work.
• I don't think I am going to throw away these areas that I found for solar panels, yet, but I don't really have to decide on Bimini location yet either, I fit 2 panels off the stern railing to start with (as Misfits and others have advised.)

I am going to try to anticipate and design around these issues, and thank you Salty Possum for sharing your experience, it has alerted me to really address and consider that problem and engineer this properly.
Darn small boats get to be a real conundrum!

I've been reading more about parallel and series connections with respect to shading.

Background:

• Assume the Companionway cover panel is not installed for the moment.
• Series connections increase voltage and the amperage stays the same, so there is a cost savings in cables because the cables can also stay the same. However series panels are worse in the event of shading because all the panels are affected.
• Parallel connections increase amperage and voltage stays the same. Heavier cabling wire is required to carry the additional amperage. Parallel connections are better when shaded because each panel stands alone with respect to shading.

Shading Statement:

• Considering and accepting the fact that when on port or starboard tack the sails may shade either the port or starboard panels. Going downwind, all the panels will be shaded or none of the panels will be shaded. What is the best way to wire the panels?

Wiring Alternatives:

• Best wiring - Each panel wired back to its own MPPT controller. Maximizes the amps produced. Requires 4 MPPT Controllers. Expensive.
• Second best wiring - Port panels wired in series back to its own MPPT controller. Same for Starboard panels. Less cost for controllers, some remote possibility of minor shading on the two panels in series that causes loss of power production.
• Third best wiring - As above (second best), but wire the port and starboard side to a single MPPT controller in parallel, thus keeping the port side and the starboard side independent with respect to shading. This is a less expensive solution that preserves the advantages of the second best solution, because it requires just one controller and keeps port and starboard panels independent with respect to shading.
• In all cases the wire should be sized for less than 3% drop. The first wiring solution will require the most wire, but it will be of smaller size. The second wiring solution will require less wire of the same size as the first. The third solution will require some additional wire but likely less than the first solution.

What do you think about the wiring suggestions above?

[rgleason]

Misfits, I really like the idea of using the swim ladder for support of the panel. No new part or costly mods are needed. Right now my swim ladder is on the side and stowed in the starbd locker. Would like it integrated however.


Salty Possum wrote:

It has an older Siemens panel in front of the dodger. It functions but actually adds nothing as it is nearly always largely shaded and utterly pointless as far as I can tell. I am considering just taking it off and mounting fuel cans there. It would be nice to be able to mount it where I can adjust it to the sun for extra power when I need it.

This is interesting. Are you most often tied to a dock or on a mooring, or sailing? My area there is 21" x 37" wide. I am told that it is best to have two separate panels (p & s) which means they are small say 50w and thus have fewer cells and only produce 16 cells x .5v = 8v about. When you have one full panel there is always some part of the panel shaded, causing lower output. I don't have a big enough area for two panels at that location so perhaps that should be a low priority as these smaller panels are more expensive too. (Incidentally I just found out Fly Solartech makes a smaller 50w split cell panel with 32 cells x .5v = 18v which puts out about 2.6 amps, so that works much better with MPPT controllers.