Solar Power Boat

Discussion in 'Boat Design' started by Nickname123, May 9, 2017.

  1. Nickname123
    Joined: Aug 2014
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    Location: Viet Nam

    Nickname123 Junior Member

    Hello all,

    We are a composite boatbuilding factory in Viet Nam. Our strength in this field is manufacture Kayak, Canoe and some small speedboats.

    Now, we plan to build a new boat with electric propulsion and this electric motor is completely powered by solar energy.

    The boat we plant to build is made by Composite and it's engine is electric engine and we use solar panel to supply energy for this engine. The capacity of the engine is about 8KW ~ 10,7HP.

    You can see the link for more information: . Our boat is the same with this project.

    But now, we got some troubles with Viet Nam Register. The problem is Viet Nam Register don't have any technical regulations to control solar power boat. They require us supply them some regulations related to solar power boat and they will consider these regulations before accept for us to build this boat.

    So, have you ever try to built this type of boat? Can you guide us how to go with them or show me where we can find the technical regulations for solar power boat? If no, anyone can introduce for me any designer can do the design for this type of boat with DNV/ABS/Lloyd approved?

    Hope to receive replies from you guys.

    Thank you very much.
     
  2. BertKu
    Joined: May 2009
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    Location: South Africa Little Brak River

    BertKu Senior Member

    First at all you should make a proposal for the buoyancy .i.e. if your proposed boat is made of GRP and wood. minimum of 60% of total weight , hull, motors, crew, batteries etc. the buoyancy should be a minimum of 60%.
    2nd. Make a proposal for the type of fire extinguisher which can deal with the type and powerful batteries.
    3rd Make a proposal for fuses and safety for short circuit of batteries.
    4th Make a differentiation proposal for inland or on the sea of your boat.
    5th try to find out how the Swiss has arranged their insurance for their solar boat.

    Maybe some other members can add a few regulations to the above,
    Good luck with your project.
    Bert
     
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  3. BertKu
    Joined: May 2009
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    Location: South Africa Little Brak River

    BertKu Senior Member

    I would add, that the battery enclosure must be suitable for the batteries used. i.e. watertight for lithium batteries and sufficient ventilation for SLAB's and open Lead acid batteries.
    Also maybe a suggestion for the type of connectors used.
    Also something about the thickness of the gold layer. (layer on the connector points)
    Cabling standards.
    Bert
     
    Last edited: May 12, 2017
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  4. BertKu
    Joined: May 2009
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    Location: South Africa Little Brak River

    BertKu Senior Member

    Is there a specific reason why you cannot build it yourself without a designer. Have a look at www.torquido and www.ocean
    Is there a specific reason why you need a designer for your boat to produce regulations? Are you not able to do it with a local electrical engineer?. Have a look at www.torqeedo.com and www.oceanvolt.com . Also I would add that the copper cabling must be tinned.

    What is missing in your request to the forum is
    a) the use for the boat, inland or sea
    b) should the solar panels be the only source of the energy for the 8 Kw motor and only a small battery pack backup (1 - 2 kwh)or a massive 24 hr batttery pack i.e. something like a 100 Kwh pack.
    c) must the boat be suitable for paid passengers
    d) your 10 solar panels will only give at 12 o'clock midday approx. 2,4 Kwh energy this is not enough for the 8 Kw motor. We can therefore conclude that you have a battery pack somewhere hidden. refer tp point c)
    d) only 1 motor or 2 ( in case on the sea)
    Making a solar boat is not difficult, what is difficult to do the right combination of charger, voltage regulator, size of battery pack and the correct layout of motor/battery and motor.

    A local electrical engineer will be able to give you the best advise. That is my opinion.
    Bert
     
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  5. Nickname123
    Joined: Aug 2014
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    Location: Viet Nam

    Nickname123 Junior Member

    Hello Bert,

    Sorry for my late reply but, many thanks for your reply.

    1) The problems we have got is:

    a) Viet Nam Register (VR) does not have any regulation to control the solar power boat. That's why we need to give them some regulations for their reference, and then when they agree with the regulations we supply they will allow us to do this project.
    b) And caused by Viet Nam Register does not have any regulation to control the solar power boat, nobody in Viet Nam can do the design for this boat, designers don't know what regulations they need to use to design this boat.
    c) That's why we need some regulations related to solar power boat or we should get the design approved from foreign Registry Organization and VR can allow us to use this design.

    2) There are some answers for your questions:

    a) We use this boat in inland.
    b) We need about 8 hours to full charge for 8KW engine, we use 6 solar panels and 6 batteries (200 Amp 12 V AGM batteries). Yes, the solar panels are the only source for motor and we don't have any energy backup for it.
    c) Yes, the boat is suitable for 6 persons.
    d) The maximum power we get for each solar panel is 250W per hour, we use 6 solar panels means we need 7-8 hours to get full charge for batteries if we get good sunshine.
    e) We have just use 1 engine on the boat.

    Hope to receive your more comments.

    Thank you.

    Duong.
     
  6. BertKu
    Joined: May 2009
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    Location: South Africa Little Brak River

    BertKu Senior Member

    Hi Duong, I suggest that you refer them to SAMSA website. www.samsa.org.za They are the South African Maritime Authority, due to the high volume of shipping traffic around the Cape Horn to Europe, well respected. They have the rule, if it is for inland use and less than 15 horse power (11.3 Kw) you don't need a shipper license provided it is for recreation and sport purpose. However you need in all cases a buoyancy certificate. That will be also for you the most important issue.
    secondly you have 8 solar panels on the roof i.e. some 160 kg at +/- 2 meter height. That needs some stability consideration, i.e. the boat should not be to narrow, special if you 6 passengers all see something of interest and move all of them to one side of the boat. Have a look at the website and maybe you can find some information to pass onto your VR. If you have paid passengers the issue changes. The rules are more stricter. But search on their website.
    You also have to consider the fire extinguisher, it has to be suitable for electrical fire. i.e. dry foam or whatever is suitable for batteries having a bad time.
    Hope that this could help you.
    Bert
     
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  7. BertKu
    Joined: May 2009
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    Location: South Africa Little Brak River

    BertKu Senior Member

    Hi Duong,

    I can understand that your VR is concerned. You haven't mentioned what Voltage you run your motor on. I assume 72 Volt. If that is the case, it means that at an open voltage of your solar panels and your 6 solar panels are in serial, you have an open voltage of a minimum of 108Volt DC. That is deadly with DC . A body resistance can be as low as < 25 KOhm special on a wet boat with wet hands . Your heart will stop at 20 milli Ampere and with DC, your hand will cramp and does not let loose at that kind of Voltage. You will be brought to the maritime court.

    I would say the following.
    Use 2 brushless motors at 36 Volt maximum. The open voltage will be then 54 Volt, which is at the border.
    If you use 1 motor of 72 Volt. The rules should be :
    a) High Voltage signs by all connection panels.
    b) Double insulation. That should also be preferable by 36 Volt
    c) Sign by the solar panels, by working on the panels, the solar panels must be covered.
    d) connection boxes locked with a lock. So that no passenger can fiddle with the connections and touch it.
    e) 6 Ampere maximum per square millimetre. i.e. at your current of 120 Ampere, 20 mm2 cable.
    f) cable copper must be tinned.
    g) Fire extinguishers suitable for electrical fires . i.e. dry foam
    h) each passenger and crew must have an VR approved life Jacket
    h) Buoyancy must be greater than 60 % included skipper and 6 guests .i. if your boat weights 400 kg bare, 120 kg for solar panels 30 kg for aluminium uprights to hold the panels, 7 x 75 kg crew = 525 kg engines 30 - 40 kg if 2, 7 Life jackets 20 kg. 6 batteries 360 kg extra; ancre, food, drinks etc. 100 kg Total 1595 kg, you need to find some sealed foam area covering at least 1 m3 to 1.2 m3 area
    Good luck.

    Correction. You later stated 6 batteries and 6 solar panels, I still had the photo from the 1st thread in mind.
    Bert
     
    Last edited: May 31, 2017
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  8. BertKu
    Joined: May 2009
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    Location: South Africa Little Brak River

    BertKu Senior Member

    Hi Duong, Your concept does not make sense for me. Your have 6 solar panels and a 250 watt solar panel at its peak gives only 13.8 Ampere. 13.8 x 72 Volt = just under 1 KW. I may have misunderstood your English, you stated that the solar panels are the only means for powering the motor, >>Yes, the solar panels are the only source for motor and we don't have any energy backup for it << .Why a 8 Kw motor using only 1 Kw?? You can only use your batteries to power the electric motor you stated and if you travel at full blast for a day, your batteries are nearly half depleted. The second day and your batteries are nearly flat. If you use a brush less motor, the torque at low revolutions will help you. If you use then only 1 Kw, your batteries stays charged. That maybe the reason why on the photo in thread 1, they have added 4 extra solar panels. I personally think you need 12 solar panels to travel comfortable. i.e. 2 Kw and then occasionally 3 or to 8 kw. Could you elaborate on this? Many thanks. Bert
     
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  9. Nickname123
    Joined: Aug 2014
    Posts: 25
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    Location: Viet Nam

    Nickname123 Junior Member

    Hello Bert,

    Thank you very much for your reply,

    1) About maximum power current on boat. Yes, you are right, this's very dangerous and we have to careful with it. You can see the catalogue for solar panels and batteries we plant to use in the attachment.

    2) The maximum power of engine is 8 KW. But, in fact, we only use about 4~5 KW and the batteries can be charged while operating (although this can damage the battery's lifespan). We only need the full power when manoeuvring or speeding the boat up, after that we just run on 50% in average.

    If you feel my project is not good at any point, please feel free to let me know. Your comments are help me so much.

    Thanks.
    Duong.
     

    Attached Files:

  10. BertKu
    Joined: May 2009
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    Location: South Africa Little Brak River

    BertKu Senior Member

    Hi Duong, Unfortunately we could not open the PDF files.
    I feel the system is not optimised in what it could be. Your comment >>although this can damage the battery's lifespan<< is not true, Your problem is that at 3 - 4 Kw the solar panels are delivering energy direct to the motor and the balance is drawn from the battery. Until you have reach 20% of your battery power. It is never good to deplete, even AGM batteries fully.
    I have lots of questions. To enable us to help you instead of guessing :
    a) what kind of motor do you use, normal DC motor, Brushed motor, Brush-less motor, out runner, normal one with the coils on the outside and the magnets on the axle.
    b) what voltage
    c) how is your control circuit, switch mode to control the power or with sliding resistance
    d) will your 72 Volt battery compartment have a disconnect switch when the cover is opened. The kind with 200 Ampere blades made from copper. Whereby there is no danger of touching 72 Volt and possible die
    e) is your battery compartment ventilated, yes, no
    f) what is your cruising speed, 4 knots, 5 knots 6 knots?
    g) what is the size of your propeller.
    h) what is the maximum motor revolutions at that cruising speed.
    i) what is the maximum motor revolutions at full battery voltage

    I still feel you should consider 12 panels and not 6 . The solar panel manufacturer are fooling us with the power calculation. It is calculated at open voltage i.e. 250 watt / 18 Volt = 13.88 Ampere, which normally is the short circuit current, a solar panel can deliver. Expect if you use a fancy converter.
    If you feel, you don't want to disclose confidential information, give me a private message/
    Bert
     
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  11. BertKu
    Joined: May 2009
    Posts: 2,439
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    Location: South Africa Little Brak River

    BertKu Senior Member

    Hi Duong,

    You should be aware of the following problem when using Brushless motors and Pulse Width Modulated speed control together with Lead Acid Batteries .
    If you cruise less than the 13.8 Ampere from the 6 solar panels, i.e. 72 Volt x 13.8 = +/- 1 Kw , which will for a 7 meter boat and 1600 kg relates to +/- 2.5 miles per hour, Your battery will not provide any energy.

    If you cruise at +/- 50 Ampere, i.e. 72 Volt x 50 = +/- 3,5 Kw, your battery will feed the balance of 36.2 Ampere from the battery. The problem you should be aware of, is that the peak currents drawn from your battery will not be 200 Ah : 36.2 Ampere, another 5,5 hour >>> but less. It will probably 4,8 hour. This is due to the high currents of a brushless motor shown as average of the 36.2 Ampere, but could be peaking at 90 or 100 Ampere.

    A lead acid battery manufacturer state the 200Ah at a certain current ratings per hour, probably at 20 Ampere for 10 hours and at 100 Ampere probably 1,7 hour.

    This is not a problem for lithium batteries. Therefore I sill suggest that you consider not 6 , but 12 panels. You probably with a 7 meter and 1600 kg boat can cruise at a reasonable 6 to 8 miles per hour without consuming too much energy from the batteries.
    Bert
     
    Last edited: Jun 4, 2017
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  12. BertKu
    Joined: May 2009
    Posts: 2,439
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    Location: South Africa Little Brak River

    BertKu Senior Member

    Hi Duong,

    Very much appreciated to receive all your detailed information.
    Before you waste a lot of money , are you convinced that you will have a good product when you are finished with your design?
    Your battery:
    20 Ampere at 10 hours Voltage slightly lower.
    1 hr rate 136 Ampere and Voltage is dropped to 9.6 Volt. i.e. with your 6 batteries only 57.6 Volt and not 72. ( 7,8 Kw for 1 hour) Where is the current coming from for your 10,5 Hp or 8,7 Kw motor? You kidding yourself, or better said, the supplier is not given you a good deal

    In my small solar boat, with only 1 to 2 Hp 24/36 volt motor, I could not understand why my batteries were depleted so fast, until I made a 130 Ampere electronic over current system and to my surprises sometimes I trip my 130 Ampere fuse. (No sweat, it takes 1 second to reset) . This is at 24 Volt, at 36 Volt I have to very slowly increases my power not to trip the fuse. The reason is that a brush less motor has the torque at 1 revolutions and is roughly the same at full speed and it is created by very high currents for a very small time period. My solar panels are at open Voltage 21 Volt and gives 11.8 Ampere.

    Now can you think what happen with your 8 KW motor (10,5 Hp) your currents are sky high and your battery is depleted very quickly. I estimate your currents to be at 72 Volt roughly 120 Ampere continuous, however if your controller is turned down to a lower speed, the currents are even much higher than 120 Ampere probably 500 Ampere in view that your motor resistance is not build up enough. Your battery cannot give you much pleasure, except when you work with additional buffer capacitors. (Mine is 68.000 uF) solar panels are also 19 Kg.

    Then, your solar panel is at open voltage of 37.2 Volt and maximum 8.03 Ampere. (= 250 watt) but with a battery connected directly, it still only gives you 8.03 x maybe 13,5 Volt (= 108 watt and not 250 watt).
    OK> now you can ensure that your system has a MPPT (Maximum power point ) controller and that gives you probably 15 Ampere. Nothing for Nothing and I don't believe that the efficiency is better than 80% and therefore I do not have the confidence in getting the speed of 6 knots for very long boat trips and only 6 panels.

    Rather look at panels which gives you more current for the same weight or increase it to 12 panels smaller panels with lower open voltage and higher current per panel for the same price and weight. Also if you have only a 2 Kw Lithium battery pack (weight 20 Kg), you will have more pleasure than your 14.4 Kw 396 kg Lead acid batteries and have to push 370 kg more through the water. This cost you at least 0,5 to 1 Hp more and is regarded by me as waste. Your lithium batteries can handle very high currents without all those hidden problems.

    Good luck and maybe you can make the boat slightly wider with the same length and have more solar on the roof. To make it safer, keep your passengers in the middle.
    Bert
     
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