Author Topic: Inboard electric boat conversion  (Read 6927 times)

Offline Dimonic

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Inboard electric boat conversion
« on: April 30, 2014, 06:34:26 PM »
I am looking to convert a boat previously powered by an Atomic 4 engine (and Alberg 30 sailboat). The rule of thumb seems to be 1kw / ton for boats up to about 26 ft. The boat is 9000 lbs, or about 4.5 tons. Therefore perhaps a 5kw motor may do it.

I see the water cooled motor is currently unavailable. Is this coming back at any point?

It would seem I need a BLDC 5kw motor, an HPC300 brushless controller, and some kind of 48V battery pack.

Does this look like a suitable application, and will the water cooled motor become available?

Offline Rusina

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Re: Inboard electric boat conversion
« Reply #1 on: June 18, 2017, 06:14:22 AM »
Hello,
I led the conversion of a 36 foot boat into an electro-solar boat from the GM range.
It is therefore possible in reality.
In my case the biggest problems to solve were:
- the release of the large Mercedes 6-cylinder engine,
Coupling and in particular the return of the thrust to the hull.
The boat made a little less than 10 tons and I opted for a BDLC engine 10 kW 48 V with its controller VEC500, it is mainly for a river use.
I did the first tests with 4 AGM 100 Ah batteries mounted in series.
I use a double chain transmission with a 19:25 ratio, with 12.7 double gears for now.
The boat is almost electrically autonomous with a set of photovoltaic panels high-yield and allows me to move between 3 and 5 km / h depending on the sunshine.
The next electrical buffer is provided with 10 kW of 48 Volt LiIium batteries.
Still a few things to improve on cooling and optimizing the controller settings and this should be OK.
What a pleasure to sail in inland waters, without noise, odors, fuel!
Nautical greetings.

Offline Danned

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Re: Inboard electric boat conversion
« Reply #2 on: July 15, 2020, 05:35:49 PM »
Just a note, I analyzed the torque vs power rating of the 5KW vs 10KW and realized that you need less power on the 10KW to reach the same torque. For that reason I put a 10KW into my 35' hughes. I think the 5KW would of been fine but it would be topping out to get to hull speed. I'm running at hull speed at about 5KW but I also have a 1.92:1 reduction ratio of motor to shaft. Displacement 12,000 lbs.

The 10KW has so much torque I likely could run this 1:1 with no reduction and then I'd be about about 2.6KW for hull speed.

I also have a 2 blade sailboat prop, switching to 3 blades would reduce power demand about 20% too. Just thought I'd add my 2 cents of what I learned with my recent conversion.