Off-Grid Boat: DIY Electric Boat Motor Assembly - Ep. 10

[@modularhippo]

Join me in building a powerful off-grid electric boat motor-step into the future of sustainable boating!

[@HarjoK]

Hi, I have (a new version) of the 20kw goldenmotor motor, specially build for boats , working on my workbench.. I have fiddled a lot with the new controller settings to have the motor work as I want… I’m in contact with the Chinese guys for support and questions. I’m looking forward what you bump into with the default settings….keep up the good work!👍🏻

[@modularhippo]

Hey Harjo, thank you for reaching out:) I was looking at the 20kw but if I remember it correctly it pushed me towards 96v instead of 48v hence deciding to run 2 x 10Kw. Looking forward to actually start to run them and my first task will be to see if I can run the motors against the same RPM controlled by one throttle. You are way ahead of me so I have a feeling that you will be a valuable contact down the line:) I have a good contact at Golden Motors. Although not technical he tends to find answers needed so far but let's see what happens when my questions get a little bit more bespoke to my need:) Thanks again for reaching out and let's stay in contact!!

[@HarjoK]

@@modularhippono problem, let stay in contact! 😊 for me it’s also a big hobby and learning project. What I have for motor is not on there list or website. It’s a new version based on the 20kw motor but than for 48v and differently build for a lower rpm (max 2800 I believe) but higher torque. It will end up have power for 10-15kw They use this motor now for the IB15 (the inboard all in one)

[@modularhippo]

@@HarjoK - Sounds exactly what I was after and would have needed. 4000 RPM (my motors) just lead to allot of gearing to get the torque up. Although 2 motors give some degree of redundancy, 1 motor is less moving parts and less things that can go wrong:) There will always be development in this area so I will just work with and be happy with the motors I got:) - Will be interesting though to follow your project.

[@MarjanMitic-c8y]

Great job Henrik! Happy New Year my friend..

[@modularhippo]

Thanks Marjan, hope you and family had a great time👍🏻👍🏻👍🏻

[@bruseidon]

Nice project. I’m still planning the setup and order it soon. Keep on! Nice job!

[@modularhippo]

Hey Bruseidon! Happy 2025! Thank you for taking an interest and comment. When you say 'planning the setup' do you then refer to the motor build or building the Kiribati 36?:) Either way, great to hear and let's stay in contact as two brains are better than one:)

[@antonygilbert9695]

Always the best :)

[@modularhippo]

Thank you Antony!! Bring on 2025!!:)

[@antonygilbert9695]

@@modularhippo Happy great 2025 to you too Henrik :) Rock0n :) !

[@Lagittaja]

I'd say good choice overall not to use those fingerguards/"dust filters". I would recommend fan finger guards made from metallic wire. They should be among the least restrictive to airflow. But dust filtration overall just drops your cooling performance quite a lot and with a radiator that dense, the radiator itself is already functioning as a kind of a filter with you placing the fans as pull instead of push. You could just accept the fact that eventually the radiator clogs and you'll have to blow it clear with compressed air. Filters just change the thing you have to clean and they might clog sooner and if you don't remember to clean them, the cooling performance will still suffer. I just don't bother with filters and every month or two just go pffffttttt with an air hose. One other option as a filter could be mesh type filters with the fans in push. These are made with an aluminium frame and a stainless steel mesh filter sandwiched between the aluminium frame. You can find these with for example "stainless steel 120mm fan filter" search term, local IT shop probably has them if you want to try them out. Either of these two product types I've mentioned shouldn't cost more like 2-4 euros a piece

[@modularhippo]

Hey Lagittaja, hope you had a great New Years!! Big thank you for your feedback on the fans. I think I will leave them of and completely and just clean them regularly. Need all the cooling I can get so guess the best way forward:) Thanks again Lagittaja!!

[@StingrayBay]

Maybe I missed it... but why are you going for air cooled radiators on a boat? Most boats have water cooled heat exchangers, which are quiet, don't use much power and have an endless heat sink... basically the opposite of your setup.

[@modularhippo]

Hi StingrayBay - Thank you for comment and feedback. I guess you can use both methods. The reason for me deciding to run a closed (none seawater cooled) system for these water-cooled electric motors is that I want to avoid pumping seawater around (to avoid issues sometimes related to this, leakage, corrosion, blockage ). Being an aluminium boat I am trying to avoid potentials of seawater inside the boat in any form. I am used to fan cooling on my old motorcycles so picked the method I felt comfortable with. If not optimal then a possibility that I will look into heat exchanger. Who knows, I might be missing a trick here. Super grateful for you taking the time to give feedback, appreciated. Thanks StingrayBay!

[@stegra5960]

It wouldn't be necessary to use seawater for cooling directly. A skin tank welded within the hull will transfer the heat out. This is very common on steel hulled, diesel powered boats which have significantly more heat to disperse. I'm using the exact same motors on my 15m x 4m steel widebeam, though my configuration of the motors is very different, with one mounted directly in front of the other with the belts driving the shaft about 250mm apart. I have a small skin tank (600×600×50mm) which I'm advised will be more than sufficient.

[@StingrayBay]

@@stegra5960 I was thinking the same thing as aluminium is a great conductor it wouldn't have to be welded though as thermal grease would transfer the heat really well

[@modularhippo]

@@stegra5960 Thank you for feedback and thoughts. Very interesting indeed. I am building my 'forever boat' so if there are better ways then I am all up for that. At the moment I have all the components for this design so will take it to the end but as the model you mention has so many fewer parts I would love to put the skin tank in place as redundancy just in case I ever come to try it out. By the nature this one is hard to bench test unless boat is in water and as mine is being built it is hard to compare both setups running. - Just so that I get this right, a closed system where the cooling hoses are connected to both motors, and both motor controllers, a circulation pump moving the water around and through the skin tank and besides the expansion tank/reservoir that is it. Being an aluminium boat I would most likely have an aluminium skin tank. if understanding it correctly it is more or less just a long tank with a divide in the middle to force the hot water to take a long path through it. Skin tank is either mounted to the hull under water level, or even outside (keel tanks). I like your motor setup, I had to build against a particular space on sailboat so motors in a line was not an option (can see the benefits though):) - You don't happen to be in the UK by any chance, would be nice to see the setup if you ever drive past North West area. Thanks again for feedback as interesting stuff:)

[@modularhippo]

Thanks again StingrayBay for pointing me in this direction. I will most likely make provisions for both (as a skin tank has so few components).