What do you think about this solar set up?

[tradrockrat]

I've been researching solar for a while now and after reading all the...polite disagreements...this subject has on the internet, I think I have a starting point.

I am TOTALLY open to changing this completely as I have no solar power anything yet - no panels, , no MPPT controllers, no wiring, etc.

I'd love to hear your thoughts on why the following hypothetical set up is crap, awesome, or meh:

An Amazon bought set up consisting of four 200W 24V solar panels run in two sets of parallel - a port and a starboard. Each set running to one Victron 100/30 MPPT smart controller. They would be mounted on the arch with two on the top of the arch and two on the sides of the arch that can be swiveled up (much like the typical life rail mountings people do).

These would make 800W @ 24 V to charge a 12 V battery bank that currently sits at 464 AH of Firefly Batteries (may add more firefly's if we have room/ need - thinking potentially 696AH)

Potential shade problems include a wind generator and the radar dome is mounted in the center of the arch on a small raised platform.

The panels I'm looking at are from companies like Newpowa, Sungold, and Rich Solar.

Similar numbers from each:

Rate Maximum Power:200W

*Voltage: DC 24V

*Open-Circuit Voltage:45.20V

*Voltage at Pmp(Vmp):37V

*Optimum circuit current (IMP): 5.41A

*Short-circuit current (ISC): 5.82A

*Cell Efficiency: 18.48%

*Module Efficiency: 15.67%

*Temperature range:-40℃ to +85℃

*Maximum system voltage: 1000V

*Output tolerance:±3%

*STC: Irradiance 1000W/m2

*Module temperature 77℉

So what do you think? Thanks in advance

[donradcliffe]

A few thoughts:

A '24v' panel that has a 45 VOC is not a 24 volt panel, as far as your MPPT is concerned it is a 45 volt panel. However, the 45 VOC means that it has half the current that a 200W 20 VOC panel does, so less line losses with the same standard wiring.

The Victron 100/30 has a firm limit of 99.9 volts VOC. Two controllers will give you some redundancy if one fails, and lower shading losses.

Your wind generator and radar shade will cut your output by 50% a lot of the time if you wire in series/parallel. You will lose more than the wind generator puts out.

Do not be sucked into buying flexible panels.

[tkeithlu]

How many amp hours are you trying to get out of this rig? I don't see a calculation that would tell me that wind plus solar will supply your energy needs, and you didn't mention a genset. If I were researching this, I'd ask a few people on the forum who live with solar rigs (I don't) what percent rated capacity they actually get out of their rigs per day.

The assumptions in ratings include 90 degrees to the sun at noon on a clear day in the tropics. Then you start whittling down - angle, clouds, latitude, battery efficiency, and a bunch more that to me say only empirical numbers - what people get out of their systems - are likely to be useful in your planning.

[DefinitelyMe]

Regarding post #2: +1
Regarding post #3: We have a similar setup to what you are proposing, but smaller. 200W on each side, series-parallel. We typically get 60Ah/24h in the winter and 100Ah/24h in the summer at 32N.

[tradrockrat]

Thanks all for the replies.

To reiterate - this is NOT a series / parallel set up. The idea is two sets of two panels each run by their own controller. Each set is two 200W 24V panel set up in parallel ONLY together. Series seems counter intuitive on a boat that will have some sort of shade problem almost 100% of the time. That's why I'm looking at large 24 V panels instead of smaller 12V wired in series. But let's not go down that rabbit hole since there are lots of threads on that already.

A portside set of two panels wired in parallel producing 400W @ 24V and a starboard set wired in parallel producing 400W @ 24V. Each set would have their own Victron 100/30.

No genset.

I did not include data calculations of energy needs because they lead to off topic digressions. I agree 100% that I need input from people with real life experience and numbers, not spreadsheets and imaginary scenarios of perfect weather / sun / latitude / angles, and the unicorn of "no shade".

I'm not asking if this set up will take care of my energy needs - let's pretend it will. Let's pretend that whatever this set up actually produces, that's my power consumption.

I'm asking:

What WILL this set up actually produce in real life (does anyone have experience with a similar same?),
is it a good set up in actual practice for a cruising boat living at anchor more often than not
is there any experience with these panels to share
How about inexpensive 24V panels in general?
is this the right Victron (100/30) for this set up?
Why am I horribly misguided about solar
How ashamed is my mother for even giving birth to such an idiot
Bonus points for, "Dude, everybody knows the best solar set up for circumnavigators living on the hook is ________________."

Thanks again all. Every reply really helps me wrap my head around the issue better, gives me insight to where I'm missing important considerations, and helps me frame the questions more concisely.

[noelex 77]

Your approach is sensible. My only comment is the solar panel efficiency is quite low. This results in larger panels for the same wattage, or less wattage for the same size. However, finding high efficiency panels around this size is difficult so you will need to some searching to find something better. Otherwise the chosen equipment and set up looks good.

Originally Posted by tradrockrat

I'm asking:
What WILL this set up actually produce in real life (does anyone have experience with a similar same?),

There are formulas for average output quoted on forums, but they are only useful for a narrow range of locations and seasons. Our solar panel output varies around 10x depending on our location and season. A single average number is of very limited value, we still need to produce all the power we use. So to receive any meaningful data you need to specify the location, season etc where you hope to cruise. Hopefully then someone with first hand knowledge can answer your question.

[stormalong]

That is a lot of power, what are your anticipated loads? I have half that output on a '44 and it supplies all the power I need. It is not the size of the battery bank that matters as much as the power draw that counts.

Not knowing the wind conditions where you are, I would consider getting rid of the wind generator and think about putting the RADAR on the mast. Those two moves would improve your solar power production considerably.

[sailormed]

I would put the controller close to the batteries so you have the high voltage over the longer distance and the 12V to the batteries only a short run. Less losses.

[MJH]

Originally Posted by tradrockrat

I've been researching solar for a while now and after reading all the...polite disagreements...this subject has on the internet, I think I have a starting point.

I am TOTALLY open to changing this completely as I have no solar power anything yet - no panels, , no MPPT controllers, no wiring, etc.

I'd love to hear your thoughts on why the following hypothetical set up is crap, awesome, or meh:

An Amazon bought set up consisting of four 200W 24V solar panels run in two sets of parallel - a port and a starboard. Each set running to one Victron 100/30 MPPT smart controller. They would be mounted on the arch with two on the top of the arch and two on the sides of the arch that can be swiveled up (much like the typical life rail mountings people do).

These would make 800W @ 24 V to charge a 12 V battery bank that currently sits at 464 AH of Firefly Batteries (may add more firefly's if we have room/ need - thinking potentially 696AH)

Potential shade problems include a wind generator and the radar dome is mounted in the center of the arch on a small raised platform.

The panels I'm looking at are from companies like Newpowa, Sungold, and Rich Solar.

Similar numbers from each:

Rate Maximum Power:200W

*Voltage: DC 24V

*Open-Circuit Voltage:45.20V

*Voltage at Pmp(Vmp):37V

*Optimum circuit current (IMP): 5.41A

*Short-circuit current (ISC): 5.82A

*Cell Efficiency: 18.48%

*Module Efficiency: 15.67%

*Temperature range:-40℃ to +85℃

*Maximum system voltage: 1000V

*Output tolerance:±3%

*STC: Irradiance 1000W/m2

*Module temperature 77℉

So what do you think? Thanks in advance

You appear to have done a lot of research on the subject but your question leads me to believe you are electrically challenged like me. I am not a marine electrician either but have a six year old marine 12V solar setup of 4x140 panels with a separate controller for each pair of panels. I got my setup from eMarine Systems in FL, installed it myself and have not had a problem.

My immediate recommendation is to contact a marine solar dealer with a general outline of your project (don't be too specific) and see what they recommend and what it would cost compared to your own plan. Then ask any questions to learn how that applies to your own proposal and see how it plays out.

We electrically challenged guys don't need to reinvent the wheel. See what the professionals say...you may even save some money.

Good Luck.

~ ~ _/) ~ ~ MJH

[mitiempo]

Originally Posted by noelex 77

Your approach is sensible. My only comment is the solar panel efficiency is quite low. This results in larger panels for the same wattage, or less wattage for the same size. However, finding high efficiency panels around this size is difficult so you will need to some searching to find something better. Otherwise the chosen equipment and set up looks good.

I agree with noelex. Actually a lot of wattage for a typical 37' sailboat. If you have a fridge - typically 50 AH/24 hours + or -, and cook on propane you will be fine. On the other hand if you have a lot of electrical loads - electric stove for example - that changes things.

You cannot plan a solar system without knowing your average daily electrical usage.

I agree also with the other poster - the wind gen won't give you much and its shade is detrimental to solar output. Radar should be on the mast.

[ShawnMack]

For some of the technical details I must defer to those with more experience.

But, as a parent with many mile under my belt I can assure you that your parents are much much less ashamed and much more proud of you than you might imagine.

[tradrockrat]

Thanks again to all. These are great responses and very helpful - especially you, ShawnMack... ;-)

[David B]

Originally Posted by tradrockrat

I've been researching solar for a while now and after reading all the...polite disagreements...this subject has on the internet, I think I have a starting point.

I am TOTALLY open to changing this completely as I have no solar power anything yet - no panels, , no MPPT controllers, no wiring, etc.

I'd love to hear your thoughts on why the following hypothetical set up is crap, awesome, or meh:

An Amazon bought set up consisting of four 200W 24V solar panels run in two sets of parallel - a port and a starboard. Each set running to one Victron 100/30 MPPT smart controller. They would be mounted on the arch with two on the top of the arch and two on the sides of the arch that can be swiveled up (much like the typical life rail mountings people do).

These would make 800W @ 24 V to charge a 12 V battery bank that currently sits at 464 AH of Firefly Batteries (may add more firefly's if we have room/ need - thinking potentially 696AH)

Potential shade problems include a wind generator and the radar dome is mounted in the center of the arch on a small raised platform.

The panels I'm looking at are from companies like Newpowa, Sungold, and Rich Solar.

Similar numbers from each:

Rate Maximum Power:200W

*Voltage: DC 24V

*Open-Circuit Voltage:45.20V

*Voltage at Pmp(Vmp):37V

*Optimum circuit current (IMP): 5.41A

*Short-circuit current (ISC): 5.82A

*Cell Efficiency: 18.48%

*Module Efficiency: 15.67%

*Temperature range:-40℃ to +85℃

*Maximum system voltage: 1000V

*Output tolerance:±3%

*STC: Irradiance 1000W/m2

*Module temperature 77℉

So what do you think? Thanks in advance

You have nothing in series - good!

As to the controllers, the only way you could improve there, would be one controller per panel. Worth it? Perhaps not - the two in parallel is probably fine.
The panel efficiency seems quite low I have to say - more like I would expect from semi-flexibles.
On that - we have three semi's, and after a full five years exposed 365 days a year, they are still performing well, and they are non-branded ones I bought online (aluminium substrate).

Within reason, the higher the panel output voltage, the lower the loss in cabling, so efficiency, and output voltage would be two factors on my shopping list.

Depending on the mounting arrangement, you might also like to consider double-sided panels - the additional energy from the back side can be very worthwhile.

Just a tip. The black plastic termination covers typical of so many panels, are just that - plastic. We all know what UV-C does to plastic - even when with rigids, those covers are under the frame. I snap the covers off, and give them a good several coats of satin black aerosol paint such as automobile vinyl-top paint. The paint can be re-done - new covers are a different issue.

[SunPoweredYachts]

Hello, I agree that there are higher efficiency solar panels available. With the limited 'roof space' you have for solar aboard a boat you want the most power in the least space.

There's more detailed ways to calculate it, but here's a quick guide to power output from solar panels to get an estimated daily yield in amp hours (at 12V)

For SunPower (23-25 % efficiency) - divide panel wattage by 3
For other mono-crystalline (15-20% efficiency) - divide panel wattage by 4
For polycrystalline (13-16% efficiency) - divide panel wattage by 5

With your 800W of solar as an example you can see the higher the efficiency the higher the power production:

SunPower - 800W / 3 = 266Ah at 12V
Mono - 800W / 4 = 200Ah at 12V
Poly - 800W / 5 = 160Ah at 12V

You can then compare this to your power consumption aboard and battery bank capacity.

It's not just about looking at efficiency though there are other fundamentals to look at eg. the 'silver lines' you see on the front of some solar panels well they're blocking the active solar surface and are a baked on aluminum paste that is porous and prone to corrosion and breakage.

Good choice of controller, maybe think about adding the Victron Battery Sense which will give more accurate battery temp and voltage readings for improved charging.

[donradcliffe]

Originally Posted by SunPoweredYachts

Hello, I agree that there are higher efficiency solar panels available. With the limited 'roof space' you have for solar aboard a boat you want the most power in the least space.

There's more detailed ways to calculate it, but here's a quick guide to power output from solar panels to get an estimated daily yield in amp hours (at 12V)

For SunPower (23-25 % efficiency) - divide panel wattage by 3
For other mono-crystalline (15-20% efficiency) - divide panel wattage by 4
For polycrystalline (13-16% efficiency) - divide panel wattage by 5

With your 800W of solar as an example you can see the higher the efficiency the higher the power production:

SunPower - 800W / 3 = 266Ah at 12V
Mono - 800W / 4 = 200Ah at 12V
Poly - 800W / 5 = 160Ah at 12V

You can then compare this to your power consumption aboard and battery bank capacity.

It's not just about looking at efficiency though there are other fundamentals to look at eg. the 'silver lines' you see on the front of some solar panels well they're blocking the active solar surface and are a baked on aluminum paste that is porous and prone to corrosion and breakage.

Good choice of controller, maybe think about adding the Victron Battery Sense which will give more accurate battery temp and voltage readings for improved charging.

I am having trouble with your claims. While more efficient cells may take up less real estate, 800 watts is 800 watts. Please show us the results of a side by side comparison from a neutral third party or delete your post.