Solar power systems

[xavpil]

I have a sailboat and 1200w of solar panels.
I will be living off grid in the bahamas

I was going to go the solar-mppt-inverter/chareger-400Ah Lithium LifeSp04 12V route.

Now I am thinking: what about those big power stations that can use solar to charge like EcoFlow and others?

1- does anyone knows about this?
2- how do I compare what my solar MPPT system would produce vs a power station? I don’t know what numbers to look at

Thanks!!!

 

[dlochner]

As a general rule of thumb, count on an average of 3 times the nominal size for solar panel output. In other words, a 100 watt solar panel can be expected to provide 300 watt hours per day. Some days will be better, some worse. So, your 1200w panels will on average provide 3600wh of power which is 300 amphours.

A good monitoring system is really important. There may be days when you will be lucky to get any power at all from your panels because of rain and clouds. With a good monitoring system you'll be able to adjust your power consumption on those days to avoid depleting your batteries.

 

[rgranger]

There may be days when you will be lucky to get any power at all from your panels because of rain and clouds.

This key point comes up often when the forum is discussing solar. I have always been curious about why you don't often see this discussion combined with a conversation about coupling wind power generation to solar power generation. It seems to me that when it is raining and overcast, you usually have very strong winds. So logic would seem to predict that if you coupled the two methods of power production, you would have very few days where you produced no power.

Am I missing some logistic snag here?

 

[WayneH]

Am I missing some logistic snag here?

On my boat, there is no wind turbine for those rainy days. Why? Because the Admiral listened to them blowing in our marina and said "H... No!"

 

[xavpil]

This key point comes up often when the forum is discussing solar. I have always been curious about why you don't often see this discussion combined with a conversation about coupling wind power generation to solar power generation. It seems to me that when it is raining and overcast, you usually have very strong winds. So logic would seem to predict that if you coupled the two methods of power production, you would have very few days where you produced no power.

Am I missing some logistic snag here?

super loud and annoying

 

[dlochner]

This key point comes up often when the forum is discussing solar. I have always been curious about why you don't often see this discussion combined with a conversation about coupling wind power generation to solar power generation. It seems to me that when it is raining and overcast, you usually have very strong winds. So logic would seem to predict that if you coupled the two methods of power production, you would have very few days where you produced no power.

Am I missing some logistic snag here?

The big issue with wind is there isn't enough of it. If you dig into the generation curves it takes a lot of wind to generate enough power to make it worthwhile. The wind has to be above 15kts to really start generating power. The link below is just one example of the wind power curve.

Incidentally this is the same issue with regen for electric propulsion on sailboats.

https://www.emarineinc.com/images/web/windturbines/primus/air-silent-x/data-image.jpg

 

[rgranger]

Thanks… So it seems like your energy time and money would be better spent on improving your storage of solar

 

[xavpil]

As a general rule of thumb, count on an average of 3 times the nominal size for solar panel output. In other words, a 100 watt solar panel can be expected to provide 300 watt hours per day. Some days will be better, some worse. So, your 1200w panels will on average provide 3600wh of power which is 300 amphours.

A good monitoring system is really important. There may be days when you will be lucky to get any power at all from your panels because of rain and clouds. With a good monitoring system you'll be able to adjust your power consumption on those days to avoid depleting your batteries.

Thanks so much!!!

 

[dlochner]

There are a good series of videos and articles about solar panels on the AltE website. Most are geared towards land based off grid solutions, however, the principles are still applicable to marine based systems. The videos linked below talk about solar panel basics and especially how the panels are rated under the STC, standard testing conditions. If I recall correctly they also talk about low light efficiency, the ability to generate electricity when the sun is at a low angle or obscured by clouds.

Intro to Solar Panels Video Series: Solar Panels 101

2-part video series on solar panel basics: voltage, current, power, Standard Test Conditions, connecting modules & mono vs poly solar cells.

www.altestore.com

 

[American_Mainsail]

I am a liveaboard as well. In the summer, I rely on my solar/battery combo for nearly all of my power needs and have a small, 2000 watt inverter generator for when the sun doesn't shine. My Victron charge controller paired with Battle Born batteries works exceptionally well. Since I installed the system, it has "just worked". No tinkering, no fixing.

Strongly lean toward the solar panels/LiFePO4 route. You will need to get electricity into the boat and store it somehow. Those solar generators are kind of a weird concept, I don't really understand the utility TBH. I can see them being useful for tailgating/beach parties/whatever, but not super helpful for what we do.

 

[dlochner]

The "solar generators" are a LFP battery and a charger/inverter in one self-contained unit. Plug them into the grid to charge or bring along a solar. I think they are best used for camping, tailgating, picnicking, emergency home back up, or perhaps on a small weekender sailboat. As a primary source on a boat, not so much. For one, we don't know how well they will withstand the salt air environment and they could be safely and securely integrated into the boats electrical system.

 

[tfox2069]

The big issue with wind is there isn't enough of it. If you dig into the generation curves it takes a lot of wind to generate enough power to make it worthwhile. The wind has to be above 15kts to really start generating power. The link below is just one example of the wind power curve.

Incidentally this is the same issue with regen for electric propulsion on sailboats.

https://www.emarineinc.com/images/web/windturbines/primus/air-silent-x/data-image.jpg

Very interesting to note that the output from wind peaks, and then drops off as the wind gets higher. Why is that?

That allows for only a relatively narrow range of optimal windspeed to generate power. Sounds good in the tradewinds; pretty unreliable anywhere else. Need to do more research to understand this particular alternative power source.

 

[American_Mainsail]

Very interesting to note that the output from wind peaks, and then drops off as the wind gets higher. Why is that?

That allows for only a relatively narrow range of optimal windspeed to generate power. Sounds good in the tradewinds; pretty unreliable anywhere else. Need to do more research to understand this particular alternative power source.

I believe that's due to the unit having to brake itself to avoid damage. It looks like the two units compared brake at different efficiencies.

 

[tfox2069]

I believe that's due to the unit having to brake itself to avoid damage. It looks like the two units compared brake at different efficiencies.

I assumed that was the case, but I need to do some more research to understand why they wouldn't just brake to the optimal windspeed for power generation and keep producing at that level. I'd guess that above the optimal windspeed they'd brake to maintain optimal output. I'm sure there's a reason - I'm def no engineer.

 

[LloydB]

'Those solar generators' I actually believe they are not solar generators because otherwise there should be some way to run them backwards and create sunlight. But that's just me. yrmv

 

[dLj]

This key point comes up often when the forum is discussing solar. I have always been curious about why you don't often see this discussion combined with a conversation about coupling wind power generation to solar power generation. It seems to me that when it is raining and overcast, you usually have very strong winds. So logic would seem to predict that if you coupled the two methods of power production, you would have very few days where you produced no power.

Am I missing some logistic snag here?

I installed the solar/wind combo. Thinking the same as you write above. Beyond the total disaster that my wind generator has been, when it was running correctly the output was ... very unimpressive.

If you look at the output curves of these dey typically start producing around 10 knots of wind. But the output there is typically maybe an amp more or less. You don't start getting decent output until you are approaching 20 knots. Then there is a small region of wind out put where the wind generator is giving you it's max output. Mine is 400 amps. That's about normal. However, then there is a decline curve because the unit has to begin shutting down due to high velocity wind and they don't want to blow apart. So in all honesty, I'll never put a wind generator back on my boat... I may keep the one I have if the company will fix it. It's still under warranty, but that's a whole other rant...

dj

 

[American_Mainsail]

I installed the solar/wind combo. Thinking the same as you write above. Beyond the total disaster that my wind generator has been, when it was running correctly the output was ... very unimpressive.

If you look at the output curves of these dey typically start producing around 10 knots of wind. But the output there is typically maybe an amp more or less. You don't start getting decent output until you are approaching 20 knots. Then there is a small region of wind out put where the wind generator is giving you it's max output. Mine is 400 amps. That's about normal. However, then there is a decline curve because the unit has to begin shutting down due to high velocity wind and they don't want to blow apart. So in all honesty, I'll never put a wind generator back on my boat... I may keep the one I have if the company will fix it. It's still under warranty, but that's a whole other rant...

dj

Thanks for that info, DJ. I've been thinking about putting wind on my boat (mostly for liveaboard winters, the winds blows a steady 15 knots almost all day on the river). Can you share what system you're using? That would be super helpful.

 

[dLj]

Thanks for that info, DJ. I've been thinking about putting wind on my boat (mostly for liveaboard winters, the winds blows a steady 15 knots almost all day on the river). Can you share what system you're using? That would be super helpful.

Not on a public forum. send me a PM.

dj

 

[Stu Jackson]

the output was ... very unimpressive.

Thanks for that info, DJ. I've been thinking about putting wind on my boat

dLj's conclusion is one that is shared by almost all sailors. I have been reading about wind generators for 25 years primarily on www.cruisersforum.com, a group of world traveling sailors. I suggest you noodle around there to learn some real world experiences. Their conclusions match dLj's and others shared in this thread: unimpressive output - even ignoring cost, and gruesome noise). The improvement in solar technology and the rapid reduction in solar cost make solar a much more attractive option for power generation. The challenge for all monohulls has always been the area available for installing panels. The importance of developing a reasonable energy budget for starters and managing consumption to match production is the real challenge. However, these days folks with adequate storage (i .e., batteries) have been going, for example, to electric galleys with induction cooktops, eliminating propane fuel from their boats. This has been made possible with the use of LiFePO4 batteries which can provide power for inverter use without the voltage sag of more traditional wet cell battery technology. The other advantage of LiFePO4 technology is that for the same given ah storage more of that stored energy can be used (wet cell 400 ah can only use 50%, LiFePO4 can use down to 10% or 90% of the stored ah). That's the Big Picture summary.

 

[American_Mainsail]

dLj's conclusion is one that is shared by almost all sailors. I have been reading about wind generators for 25 years primarily on www.cruisersforum.com, a group of world traveling sailors. I suggest you noodle around there to learn some real world experiences. Their conclusions match dLj's and others shared in this thread: unimpressive output - even ignoring cost, and gruesome noise). The improvement in solar technology and the rapid reduction in solar cost make solar a much more attractive option for power generation. The challenge for all monohulls has always been the area available for installing panels. The importance of developing a reasonable energy budget for starters and managing consumption to match production is the real challenge. However, these days folks with adequate storage (i .e., batteries) have been going, for example, to electric galleys with induction cooktops, eliminating propane fuel from their boats. This has been made possible with the use of LiFePO4 batteries which can provide power for inverter use without the voltage sag of more traditional wet cell battery technology. The other advantage of LiFePO4 technology is that for the same given ah storage more of that stored energy can be used (wet cell 400 ah can only use 50%, LiFePO4 can use down to 10% or 90% of the stored ah). That's the Big Picture summary.

My thoughts are the same. I managed to live aboard very comfortably just under solar panels and LFP. Due to conditions, mainly in the winter, that are very specific to my location I started considering wind. Based on the power curves the mfg's publish, and knowing how many kW I use from shore power in the winter, I started thinking that I could nearly heat the boat on wind based on how steadily the wind blows in my location in the winter. I've been skeptical to go for it though since it's expensive and doesn't have a great reputation in the sailing community.