Save gas and nature with solar system on the motor yacht

SerkanS · Dec 31, 2018

Dear All,

I am reading a lot about solar panels on sailboats here and I wanted to give you some ideas about my new system that I got installed last year on my 75-foot motor yacht. I think this can help people thinking about solar panels.

First, I want to start with what I saved last season to get you excited and then I will go into technical specs.

I bought my boat, a 1991 Canados, in June 2017 and I started to record most of its consumption data.
I have 2 x 1100 MAN D2842 LZE (1991) and 2x ONAN 17.5Kwh (2007) generators.

In the 2017 season, I used 927 hours of generator and 137 hours of engine.
After the solar system installed, I used only 145 hours of generators (2 genset included, so 72 hours each) and 100 hours of engine time in the 2018 season.

The main savings on the gensets were about 782 hours, equaling about 3100 liters of diesel.

On top, I had to get the service for every 200hours for each generator and this new usage saved me on the service costs as well.

During the whole 2018 season, I used only 70 hours for each generator and I guess I will start this 2019 season with just a quick oil check and no impeller replacement.
Of course, I am not including saving the nature and quite boat time with my solar power.

About the System:
First, I had 5 x 185 watts panels in the front, 4 x 135 watts panels on the port side and 4x135 watts on the starboard side installed with dedicated MPPTs (3 groups in total). The reason of three different groups was that if there is a shadow on one side of the boat, the remaining system kept its full charging capacity.

Before the project, I have listed all energy consuming equipment (I have 5 refrigerators, watermaker, oven, TV, water heater, espresso machine, toaster and such) and made a quick analysis of the power needed.

Then I decided I needed about 600-700amps every day and to install 2V Sonnenschein A602 tower batteries (http://www.sonnenschein.org/A600.htm) which should have about 12-15 years of life for the service battery group.
There are 12 x 2V batteries providing 24V with 960 Amps energy stored dedicated to service. This specific battery brand and type are designed to provide power up to its 90% capacity without killing the batteries, unlike the regular ones which need to be charged at 50% drain at most.
Needles to say, I have a different pack for the starter battery and each genset has its own start battery.

The boat used to have Victron 3000KVA invertor installed and I decided to add one more 3000 KVA invertor as daisy chain. This ended up providing 6000VA, or about 5KWA of inverting power.

On top of that, I added 2 x Victron Redressors 100A each as daisy chain to make sure we can charge 960Amps 24 V battery pack and the starter battery pack with no problem. I saw about 120-130amps of maximum actual charging when the batteries were low on power. This charge rate was going down to 20-30amps within 20-25 minutes and kept charging slowly.

Last, I used Simarine smart battery monitoring system and put monitors such as battery temperature, power to crucial lines etc as much as I can. (https://www.simarine.net/) The nice add-on was that I could also monitor the level of my black water tank as well with this Simarine.

The only detail is that I decided to change my electric oven with a gas oven to make sure the kitchen does not kill the batteries since we cook and entertain at the boot as if we are on a beach house. The oven runs almost twice a day.

The solar panel pack usually provides about 60-70 amps of 27V energy during the day for more than 8 hours.

What I missed:
I never realized how much fresh water we consume in the boat. Once we are on the bay, we stay about 10-15 days without stopping on the shore and never fill the tanks from marinas. So we have to produce fresh water for about 300-400 liters per day.
This was the only time we needed the generators to run during the day, for about 2 hours, to fill up the tanks.
My system was not large enough for the water maker (or of course the air conditioner.)

This season, I will try to upgrade the water making capacity from 170 lites per hour to 300 liters per hour by changing the membranes. I am told that with the same motor of the watermaker, I could produce more water with bigger membranes. (any idea is welcome from the community)

Also, I will try to add 4 more 185W panels to the top of bimini, and maybe, my solar system can help to run the water maker as well during the day for an hour or two.

It looks like the whole system will pay itself within 6-7 years. If the batteries can be used for 12 years and panels for 25 years as it was mentioned, this could be a great investment to the boat.
Also, I could not be happier to have a quiet time on the bay without the noise of generators.

Hope this article helps, have a great 2019.

Pascal · Dec 31, 2018

I know solar is the rage these days but 90% of what you accomplished could have been done without the expenses of solar panel. Typically in mild climate with a large inverter and battery system you can cut down generator time to 4 hours a day

The keyword is mild climate. If you need AC, you don’t have any choice but run a generator

SerkanS · Jan 1, 2019

Pascal said: ↑

I know solar is the rage these days but 90% of what you accomplished could have been done without the expenses of solar panel. Typically in mild climate with a large inverter and battery system you can cut down generator time to 4 hours a day

The keyword is mild climate. If you need AC, you don’t have any choice but run a generator
Click to expand...

Hi Pascal, thank you for the comments. Much appreciated.
However, I used to run the generators for at least 8 hours, sometimes 10 hours per day. My old batteries (600A, so at 50% discharge, provided only 300A at 24V) were three years old and maybe they were not storing a lot of energy but still, I am not sure I agree with your comment. Also, we have a three people crew including a cook. So I guess this depends on the power consumption of the boat, in our case, it is a lot.

Our solar panels pump in about 500-600 amps of energy to the batteries at 24V. So just to compensate this energy input, the generators needed to run at about 5-6 hours per day extra. So I am not sure about your comment for about 4 hours.

Anyways, thank you for the input.
Best,

Pascal · Jan 1, 2019

I ve set up inverters and battery banks on two different boats over the years. My own 53 MY and also on a 70 I used to run which was kept on a mooring all summer long

On my 53, I put over 1000 hours on the generator in the first year. Second year with an 800AH bank that went down so 300 hours. In my case i was able to run the generator just 4 hours, at mostly at night, to recharge the bank while cooking and when when using the most power

On the 70 footer, the bank was bigger as we had more refrigeration but the result was the same. 4 to 5 hours at night when we used the most power and also ran the watermaker

Since then, things have gotten better as new fridges are a lot more efficient and all lightning is now LED.

The key is to size the bank according to the boat needs and just as important to size and balance the charging system. By maximizing charging power you can minimize generator run time.

While solar costs have come down, the cost per AH still means it takes years to make it cost efficient. But there are still two massive issues. Space availability for massive solar arrays and the fact that in most popular cruising areas, it is very hard to be comfortable without air conditioning especially with modern boats which have very little ventilation

Solar can work for some but it is not the magic solution

Capt Ralph · Jan 1, 2019

Pascal said: ↑

Solar can work for some but it is not the magic solution
Click to expand...

A+

olderboater · Jan 1, 2019

As with so many solar analyses, a few important factors conveniently glossed over. First I find your title of the thread humorous though as it says "save gas" rather than diesel. I assume something lost in the translation.

Now, to the content. First, you plot savings irrelevant of actual boat usage in the two years. Yet, I see you used the engines 27% less in 2018. I don't know about time on the boat, but then discard the first 27% in savings on generators and other as you simply used the boat less. You would have saved money with no change. So, some considerable portion of your savings is likely not related to your new system.

Second, you state that "it looks like the whole system will pay itself within 6-7 years" but there is no data verifying that and I doubt seriously that's the case. Likely more like 10 years. You then make your savings dependent on 12 years life on batteries and 25 years on solar panels, both pie in the sky numbers and, in my opinion, unreasonable assumptions. Shorten those lives and the picture really changes.

Frankly, it's like many tests. It appears you wanted to prove your initial theory so made the numbers work to prove it. Your comparisons fail to meet any of the basic requirements of a scientific experiment.

Then you are dealing in a very narrow type of usage. While it may be your usage, it's not that of many. You don't run air conditioning so you automatically have a test that is irrelevant to so many of us. I can save money by not running A/C, but not going to. Ours runs constantly, so your system wouldn't work for us. Also, many boats lack the space for solar to support them.

In addition, yours is based on someone who spends the vast majority of their time at anchor, in fact more by far at anchor than actually running and virtually no time at marinas.

With all you've spent and all the work you put in, really the only thing you did was save on the hours of running the generators. I'm sure some of that reduction was just your effort to use them less. Now, I really don't care how much I run generators. Another number I question. You show your diesel usage of 4 liters per hour of generator. This is on Onan 12.5's. That would be high for running them at full load and at least triple what I'd expect at average loads. Where did you come up with these numbers? Your whole savings premise depends on that assumption. You also did things like switch your over to propane. Yet, you included those savings in your numbers when they should have been backed out as they had nothing to do with solar.

Now, did you do the work yourself or have others do it? Is all the labor added into your costs?

I suspect when all is said and done you have something like a 10 year or even 12 year payback. Unfortunately, that's what I've gotten every time I've ever done solar justifications. In Florida, due to FPL it's even longer than that and we're in a maximum sunshine area. Well, I can't justify any expenditure on that kind of payback and honestly look for much better even than your 6-7 years that I find suspect.

You went to tremendous effort and you have a system you like and are proud of. That's fine. Just don't sell it as a huge cost savings. I'm not convinced.

Now, I find it interesting you use "nature" in your title as well, but you don't expound on that. Be sure to include all manufacturing processes if you do decide to address nature.

Sailors seem to live to not run generators. You accomplished that. That's the only accomplishment that I'm truly convinced of, you ran your generators less. Not my goal in life. Perhaps you had some cost savings but not enough to justify. What other habits did you change? Less hot water? Less A/C? Less use of coffee maker?

I'm disappointed in our lack of progress in solar. The power generated by systems hasn't increased as I would have hoped. Other technologies are perhaps needed. I will jump on the solar bandwagon when I can find a system that has a reasonable payback for my home or any of my businesses. I've accepted many proposals of various types of systems, even including Tesla Powerwall's. Yet, in the Sunshine State I can't get a payback. Now, solar and Powerwall's would potentially save in a high energy cost area like Puerto Rico.

Sorry, you have a nice system and one that works for you, but your science is lacking and the proof isn't there or convincing. Certainly not there for a broader spectrum of boaters.

SerkanS · Jan 2, 2019

Hi OlderBoater,

First, thank you for your comments. I think the knowledge grows once it is shared, so all comments will increase our collected know-how. Thank you.
Second, my English is my second language, so I may miss some points and make mistakes. (Such as the one on the title) Apologies.
I just wanted to write this content because before my project, it was difficult for me to get actual data. All I had was marketing materials so I wanted to share my experience with the community and contribute as much as I can. Of course every boater has different scenarios and use cases are much different.

Last, I agree with you that this is not scientific research and some numbers could be off. And I say this being a Physics and MS in Information Systems graduate.
This content should be read as an informative piece and please note that I am not selling solar panels, batteries, or anything related to boats. I am an entrepreneur and have a technology company.

About your questions and notes:
- I used the boat at about the same rate in 2017 and 2018 in terms of days. The difference in engine hours is because we traveled less to islands but stayed in the bays more at anchor. (as you guessed right). But again, my numbers are not ready for a science test.

- In terms of return on investment, this is a simple calculation. You can safely assume it wrong because we did not complete the whole 6-10 years yet so we don't know, we are just guessing.
That is why I decided to put as much info as possible and my goal was not to make a financial investment on my boat. If I were looking to make profit, selling the boat could be the best financial decision as you can guess..) So I did not put numbers to prove my theory. Just to share as much real data as possible, giving that this is not science.

- I did not try to use anything less on my boat, in fact, I love my luxuries on the boat. But I had 80% of my lamps LED and I made sure they were 100% LEDs this season. Or like to Oven case, I chose LPG instead of electric. Because we have guests all the time and the oven is running for every meal. So you are right, we had some savings from there as well and I can not calculate this. I just wanted to add this info so that people can make their own calculations. (Oven is about 2.3KW/hr and runs about 2 hours every day)

- I got all installed professionally so all labor is included. But again, these are just to give ideas.

- As you guessed, I don't use a lot of A/C, when I do, I run generators. If your A/C is running day and night, of course, this content is not for you.

Some other facts:
I assumed my 17.5 KW Onan (Not 12.5KW) generators consume 4 lt/hr. The official specs say Onan 17.5KW consumes 3.4 liters/hr at 1/2 load and 6.5 liters/hr at full load. So given that this is a marketing material at perfect conditions, I assume 4 liters was about right. You can use your own estimation but honestly, I don't think your generator would run with 1/3 of my estimated 4lt/hr, especially under load.
Here is the official content
https://www.dropbox.com/s/axayou2rbpepcff/Onan-Generator-Hespera.pdf?dl=0

The panels produce about 500 amps at 27-27.5 volts during the day. This energy has to be generated somehow. So you can make your own calculation.
Just note that due to the nature of batteries and smart charging systems like Victron Skylla-i, you can not push this energy into the battery within 1-2 hours. The chargers just do not allow that not to kill the batteries. For this reason, the generators run for hours at 30-40amps / hour average at 27-27.5 volts for the best battery life. Once the majority of the battery is filled, the optimal charging voltage is called "float" voltage and in my battery pack, it is 27 volts.

Last, the manufacturer of my batteries says its life is 15 years. Hard to believe. I have friends who used this brand pack for 11 years. So I took a chance and tried this deep-cycle german brand. Please note that the batteries have nothing to do with the solar system. I had to buy a new set anyways and I chose Sonnenschein. My other option was to put a much cheaper regular AGM and change them every couple of years.
The last note that since solar system charges the batteries slowly but all the time, their life should a little closer to the theoric life.

Hope this helps to all readers.

Pascal · Jan 2, 2019

“The chargers just do not allow that not to kill the batteries. For this reason, the generators run for hours at 30-40amps / hour average at 27-27.5 volts for the best battery life. ”

Not true. While it s critical to size the charger for the battery bank you can charge a larger bank at a higher rate. For instance the 24v Magnum 4000w inverter I have used puts out about 110 or 120 amps in bulk charging mode which a bank over 600 AH will have no issue taking in

This alone drastically reduce charging time, fuel burn and as a result your return on investment calculations

olderboater · Jan 2, 2019

SerkanS said: ↑

Hi OlderBoater,

First, thank you for your comments. I think the knowledge grows once it is shared, so all comments will increase our collected know-how. Thank you.
Second, my English is my second language, so I may miss some points and make mistakes. (Such as the one on the title) Apologies.
I just wanted to write this content because before my project, it was difficult for me to get actual data. All I had was marketing materials so I wanted to share my experience with the community and contribute as much as I can. Of course every boater has different scenarios and use cases are much different.

Last, I agree with you that this is not scientific research and some numbers could be off. And I say this being a Physics and MS in Information Systems graduate.
This content should be read as an informative piece and please note that I am not selling solar panels, batteries, or anything related to boats. I am an entrepreneur and have a technology company.

About your questions and notes:
- I used the boat at about the same rate in 2017 and 2018 in terms of days. The difference in engine hours is because we traveled less to islands but stayed in the bays more at anchor. (as you guessed right). But again, my numbers are not ready for a science test.

- In terms of return on investment, this is a simple calculation. You can safely assume it wrong because we did not complete the whole 6-10 years yet so we don't know, we are just guessing.
That is why I decided to put as much info as possible and my goal was not to make a financial investment on my boat. If I were looking to make profit, selling the boat could be the best financial decision as you can guess..) So I did not put numbers to prove my theory. Just to share as much real data as possible, giving that this is not science.

- I did not try to use anything less on my boat, in fact, I love my luxuries on the boat. But I had 80% of my lamps LED and I made sure they were 100% LEDs this season. Or like to Oven case, I chose LPG instead of electric. Because we have guests all the time and the oven is running for every meal. So you are right, we had some savings from there as well and I can not calculate this. I just wanted to add this info so that people can make their own calculations. (Oven is about 2.3KW/hr and runs about 2 hours every day)

- I got all installed professionally so all labor is included. But again, these are just to give ideas.

- As you guessed, I don't use a lot of A/C, when I do, I run generators. If your A/C is running day and night, of course, this content is not for you.

Some other facts:
I assumed my 17.5 KW Onan (Not 12.5KW) generators consume 4 lt/hr. The official specs say Onan 17.5KW consumes 3.4 liters/hr at 1/2 load and 6.5 liters/hr at full load. So given that this is a marketing material at perfect conditions, I assume 4 liters was about right. You can use your own estimation but honestly, I don't think your generator would run with 1/3 of my estimated 4lt/hr, especially under load.
Here is the official content
https://www.dropbox.com/s/axayou2rbpepcff/Onan-Generator-Hespera.pdf?dl=0

The panels produce about 500 amps at 27-27.5 volts during the day. This energy has to be generated somehow. So you can make your own calculation.
Just note that due to the nature of batteries and smart charging systems like Victron Skylla-i, you can not push this energy into the battery within 1-2 hours. The chargers just do not allow that not to kill the batteries. For this reason, the generators run for hours at 30-40amps / hour average at 27-27.5 volts for the best battery life. Once the majority of the battery is filled, the optimal charging voltage is called "float" voltage and in my battery pack, it is 27 volts.

Last, the manufacturer of my batteries says its life is 15 years. Hard to believe. I have friends who used this brand pack for 11 years. So I took a chance and tried this deep-cycle german brand. Please note that the batteries have nothing to do with the solar system. I had to buy a new set anyways and I chose Sonnenschein. My other option was to put a much cheaper regular AGM and change them every couple of years.
The last note that since solar system charges the batteries slowly but all the time, their life should a little closer to the theoric life.

Hope this helps to all readers.
Click to expand...

Great response.

A couple of comments. When I say not Scientifically valid test, that's not meant as criticism of your report and I'm glad you saw it that way. No way one person with one boat can do such a test. You did the best you could. You have no way to create two identical situations with only one factor different.

When I indicate, using less as just part of the change, I'm talking placebo effect type usage. Once one becomes more aware they find ways of using less without even thinking. If we think energy, we save it. One you mentioned was 100% LED vs. 80%. The single easiest savings anyone can create at home or on their boat is the move to LED. We converted over 300 retail locations to LED. The original plan was to do it gradually but the savings were too great and the quality of light too good to delay. So we did it all in less than two years. Of course our savings were greater than most since we do own a lighting company among the locations. Our home is all LED and the difference is significant.

My mistake on the generator size and I do believe then the actual usage would be perhaps 70-80% of what you stated. Our experience with Onan generators was that manufacturer's estimated usage was very accurate.

One thing that didn't get mentioned was fuel cost. You are dealing with European prices. What average prices for diesel did you have over the two years. Were they constant? That's another factor though that in the US we're dealing with significantly lower diesel prices.

I still doubt the manufacturer's estimated lives on the batteries and the solar. As you indicated, no way to know for sure until years from now and no way to know even then without data from all users. I've seen many purchasers of solar disappointed in it's life though while others pleased but then finding better systems a few years later and changing. As solar technology does improve, so would numbers on a project such as yours. Have we though come to a temporary standstill on solar progress as efforts have moved elsewhere? I don't know. Whether solar or not, I'm interested in the battery results. I've followed Firefly for a while and even on it, we just don't know yet. I haven't followed Sonnenschein which have been around much longer. One thing I'd be interested in is the impact on battery banks. In single usage it's easier to gain longevity. My question is when used in banks and one fails, does it mean changing the entire bank as it does generally with conventional batteries?

As you agreed, A/C and Heat make it impractical for us. If we're on the boat, they system is running. Even for humidity control if the heat and air were not actually needed. However, I'd say in our usage, A/C would be required over 70% of the time and Heat (through the same system) about 5% though more some years.

Your report is very interesting and it appears the combination of changes you have made are working for you. Whether the payback is 7 years or 10 or 12, I still imagine you'd be happy with the results and that is good. One thing I see in your evaluation and I've repeatedly seen on boats, is solar at the very least is a practical solution. On the water, your alternative, diesel, is an expensive means of generating electricity. In Fort Lauderdale, there is at least one company concentrating 100% on marine applications. We had three look at our home and all were shocked how little electricity we use today. Also, meeting Miami-Dade and Broward wind standards is difficult. For businesses where we rent the buildings, the payback is longer than the lease. Where we own, we haven't found paybacks under 12 years. By comparison, converting to LED is about 3 years where lighting is the big electric user. We do have an estimate underway today by three providers in SC for manufacturing facilities. It would seem where the usage is equipment used daytime hours only you'd get good results. Waiting to see.

Then each state and power company has different rules. Within Florida and FPL, it's very difficult to make rooftop solar systems payback in a reasonable time as they must connect to their grid.

Please report back to us on your next year of use of your system. Yours is certainly a well thought out solution and one very worth following.

SerkanS · Jan 2, 2019

olderboater said: ↑

Once one becomes more aware they find ways of using less without even thinking
Click to expand...

I agree.
I forgot to tell you that we also have a regular size dishwasher on the boat.
My cook once told me that he was running the dishwasher once a day instead of twice a day as he used to do. Once the awareness there, everybody pays attention. So we had savings in more areas I guess.

The price of diesel is about 1 usd / liter for now. So about 3.78 usd per gallon. Not cheap.

The Sonnenschein battery brand is part of the Excite group, maybe this may be familiar. Funny thing is that the manufacturer's expected life of the battery is listed 18 years. Not 15. But again, I will be more than happy if they run for 10+ years. We will see.
https://www.dropbox.com/s/acvvis6w2s06sdy/A600.pdf?dl=0

Thank you for the comments and I will keep posting as I have new data.

Best and have a great new year.

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Save gas and nature with solar system on the motor yacht

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