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Hi Everyone, new member here, I am interested in building an electric boat. I am an electrical engineer by trade, but my experience is in microelectronics and wireless/microwave. I have very limited experience in batteries, power and energy, so this is surely going to be a learning experience for me.

It seems like there is a wealth of knowledge on this forum, so I am definitely excited to join! Looking forward to doing something cool!
 

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The tiny energy density of battery storage means a normal boat can't roam too far from shore power or ICE recharging.

Need a decent margin built in for safety.

Hybrid is more practical but of course less efficient than direct propulsion by ICE.

Solar will not be a significant source unless the whole boat is purpose built for that, which is very limiting wrt the other usual design factors.
 

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First time poster. I'm interested in the same general type of project. I have a mercruiser 6.2L powered boat, and I'd like to convert it into a hybrid.
 

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Hi Steve
You can have an electric boat BUT the power density of batteries is a lot lower than diesel or petrol
A displacement hull running at below "hull speed" would be OK for electric
But a planing hull would almost certainly eat too much power to be useful
 

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First time poster. I'm interested in the same general type of project. I have a mercruiser 6.2L powered boat, and I'd like to convert it into a hybrid.
By "hybrid", you presumably mean a gasoline-electric hybrid. Were you thinking of the same engine, or a smaller engine sized for cruising combined with an electric motor for short bursts of higher speed? Either way, it is very different from a pure battery-electric design, especially as far as the battery is concerned.
 

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The tiny energy density of battery storage means a normal boat can't roam too far from shore power or ICE recharging.
Not at significant speed, but there are at least a couple of companies selling battery-electric boats for slow cruising with multi-hour endurance. They key is to be spending time touring around near shore, not going on trips out to a far offshore location.

Hybrid is more practical but of course less efficient than direct propulsion by ICE.
A parallel hybrid avoid putting much of the power through the inefficiency of a generator and motor. And large ships are now routinely series hybrids, although all of the components (other than the battery) benefit from some improved efficiency at large scale. Even in a smaller vessel, there is some advantage in a series hybrid to operating an engine at its most efficient speed and load combination, rather than simply the prop shaft speed.
 

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First time poster. I'm interested in the same general type of project. I have a mercruiser 6.2L powered boat, and I'd like to convert it into a hybrid.
By "hybrid", you presumably mean a gasoline-electric hybrid. Were you thinking of the same engine, or a smaller engine sized for cruising combined with an electric motor for short bursts of higher speed? Either way, it is very different from a pure battery-electric design, especially as far as the battery is concerned.
Brian, thanks for asking. I’d like to keep the same engine, and augment it with an electric motor like the RAM truck’s eTorque mild hybrid.

I’d like to get better MPG, and have more power on demand for hole shots and top speed runs.
 

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Not at significant speed, but there are at least a couple of companies selling battery-electric boats for slow cruising with multi-hour endurance. They key is to be spending time touring around near shore, not going on trips out to a far offshore location.
Plenty of spots you can catch winds off a lee shore or strong currents you really don't want to run out there.

Not saying don't, just be careful.
 

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Brian, thanks for asking. I’d like to keep the same engine, and augment it with an electric motor like the RAM truck’s eTorque mild hybrid.

I’d like to get better MPG, and have more power on demand for hole shots and top speed runs.
This is definitely a parallel hybrid, and the motor/generator can even be engine-mounted, like the eTorque system and other belt-alternator-starter designs.

The efficiency benefit of a mild hybrid system in a road vehicle is mostly from regenerative braking and an improved automatic stop-start to avoid idling in traffic, but neither of these will help much (if it all) in a boat.

So to enhance short-burst performance, the battery would need relatively low energy capacity, but high power... the typical hybrid scenario.

In most details, this is the opposite of the pure battery-electric boat design.
 
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