Mounting Flexible Solar Panels on Bimini

[felizcortez]

I mocked up the panels in cardboard today and test fit them on the bimini/dodger.

The two 50 Watt panels on the rear of the bimini are a little tight so I need to check with the canvas guy on whether they are okay.

The 160W fits well on the front of the bimini and also fits on the dodger well.

However, I'm concerned about shade on the dodger (picture is below with the Boom centered and then moved to one side). I think the shading will be a problem, so I could probably split this into 2 50 watt panels, but we'd have significantly lower output.

The other option is there is a connector piece between the dodger and bimini which we typically wouldn't have up when we were sailing but would be up at anchor and I could fit another 160W panel on that.

Any thoughts?

[rgleason]

https://genasun.com/products-store/m...t-controllers/


https://www.bruceschwab.com/solar-po...e-controllers/
See the ones he lists at the bottom Genasun MPPT Boost
By splitting the panel you have fewer cells and lower voltage, so you must have boost controllers.
This wlll maximize your output. I believe Genasun Boost is the only one he suggests for these smaller panels, but it is also dependent on the characteristics of your cells too!

You will need one for each panel. I think you should check with Bruce for an installation too.

[KeelMe]

The weight of (as well as the heat generated by) the flexible panels will stretch your canvas and they will collect water and then the collected water will stretch your canvas more. I see this all the time.

Call me old fashion; we get most of our power from the generator. We also get a bit from the main engine. We have a rigid 120 Watt solar panel that produces more than enough juice to power our lights and fans. You won't see a stainless carnival on the back of my yacht.

[john61ct]

Originally Posted by rgleason

By splitting the panel you have fewer cells and lower voltage, so you must have boost controllers.

Aha, I see for that context. I thought you meant also when using higher-Voc panels.

Note there are lower-watts higher-Voc panel types too.

But the Watts per sq ft is really the key factor when space is so limited

[OceanPlanet]

Originally Posted by john61ct

Not sure where your specifying "boost" controllers is coming from.

Don't **all** MPPT 12/24V output controllers accepting a wide voltage range do both buck and boost as a normal part of operations?

I have not heard of Genasun being particularly efficient in those normal voltages, but they are in the sparse list of vendors with 48+V output capabilities.

I believe Victron is the most popular SC Bruce sells.

Victron doesn't make a voltage-boosting solar controller, only buck. Genasun pretty much rules the "boosting" controller game; Western makes one (WMarine10) that is buck/boost that is good for a few particular installations. However it's less efficient at boost (vs GVB) and buck (vs GV), although can do both which is unique.

Victron are nice with the full programmability, however needs panels with Voc = battery V+5V to start up in the morning. Which means that many of the smaller solar panels are much better off with Genasun (GVB for panels with Voc = or < battV+2V, or GV for panels with Voc >battV+2V).

On bigger panels the Victron win out, however note that on higher voltage battery systems the current is less for a given panel size. So for instance on a 48v system the panel wattage and voltage can be much higher using a Genasun 48V GVB than it would be for a 12v or even 24v GVB.

Different horses for different courses...if less shading and 12V systems then series connected panels and fewer Victrons make for less wiring and simpler monitoring. If more shading then using smaller panels with Genasun GVB's will provide much more output, especially on 24v & 48v systems.

[rgleason]

Thanks Bruce for balling me out. That's the best explanation I've seen, but it makes sense. With fewer cells in a smaller panel, when the light changes, diffuse light, foggy, early morning, evening, without the GVBoost, the panel will stop producing.

If more shading then using smaller panels with Genasun GVB's will provide much more output, especially on 24v & 48v

Bruce, Are you talking about the panel voltage? Not the electrical system?

[OceanPlanet]

Originally Posted by rgleason

Thanks Bruce for balling me out. That's the best explanation I've seen, but it makes sense. With fewer cells in a smaller panel, when the light changes, diffuse light, foggy, early morning, evening, without the GVBoost, the panel will stop producing.


Bruce, Are you talking about the panel voltage? Not the electrical system?

In that sentence I was talking about system voltage. Because the the higher the system voltage, the more panels would need to be in series to use a buck controller.... resulting in larger arrays more prone to shading. Or would need panels with smaller cut cells to increase the number of cells in series...and smaller cells are also more prone to shading losses..

So, on 24v & 48v systems the chances of using Genasun GVB's increases

[john61ct]

Originally Posted by OceanPlanet

Victron doesn't make a voltage-boosting solar controller, only buck.

In other words, can't output to a 24V bank at all unless panels are serial'd or rated at say 40+Voc?

Edit: ah that battV +5V is generalized, makes sense. Point well scored Rick

I do love to learn something new every day. . .

[rgleason]

I guess those little PV cells have to really be stacked up to well above the system voltage to be useful, then with a bunch of lower voltage panels in series the the entire series is more prone to shading and loosing all efficiency.


Thanks Bruce and John for the the understanding. If it's really going to work for you, it is not simple plug and play. Figure it out.


I wonder what governs the max voltage that a series of panels add up to for 12vdc, 24vdc and 48vdc systems.

[Paul L]

Originally Posted by felizcortez

I........

The other option is there is a connector piece between the dodger and bimini which we typically wouldn't have up when we were sailing but would be up at anchor and I could fit another 160W panel on that.

Any thoughts?

Putting a flex panel on the removable insert will put a lot of stress on the zippers. They will most likely suffer an early failure.

[john007]

That is why I have, as well as others, supported the panels on a semi rigid panel

[Eder]

If you use decent Sunbrella in decent shape no need for back up sheets. Just make sure the edges especially corners of each panel are padded. Attaching each panel with 6 snaps is much stronger than just velcro, as velcro deteriorates some each season.


I use cheap panels I paid just over $100 each on eBay ...my 1st set lasted 3 years I replaced them last year before I crossed the Pacific just in case.


I'm pretty sure in the next few years something less ugly and even lighter will become available.

[john61ct]

Originally Posted by rgleason

I wonder what governs the max voltage that a series of panels add up to for 12vdc, 24vdc and 48vdc systems.

for the panel types currently mainstream, it's number of cells.

Note that old-school nominal "12V" panels are often rated over 20Voc these days.

When you get higher than 30-something volts they **might** be called "24V" panels, but really anywhere past that they don't categorize, gets pretty arbitrary when it comes to the bigger panels designed for S&B usage,

usually very robust and good value BTW, often low as 50¢ per watt if you can pick up yourself.

Stuff sold through consumer channels are often poor value and/or poor quality.

I'm sure pricey panels sold by marine-oriented suppliers are great quality.

[john61ct]

Originally Posted by Eder

If you use decent Sunbrella in decent shape no need for back up sheets.

As long as they are mounted so that they don't flex (much).

[argonauta1]

Mine lasted about nine years but they were 1998 vintage and only gave about 30 Watts each, On balance, not worth the effort. Maybe now??