Electric motor conversation

A conversation among Whalers
dtmackey
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Electric motor conversation

Postby dtmackey » Thu May 13, 2021 12:34 pm

The topic of electric motors has come up several times before and I still do not see this as a viable solution in boats for many reasons, but some are pushing the idea and launching product offerings.

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Of particular interest is the cost, $26,995 for the outboard motor and $51,995 for the battery charger and user interface kits. Grand total of $78,990 for a 180hp motor.

Charging takes place overnight, but they don't say how long that takes. I'm also wondering about the required 220V supply needed and if marinas area equipped to handle this level of current with existing shore power strung to slips.

On comparision, lets say a Suzuki 175hp rigged cost $19,000 out the door. This would be a savings of nearly $60K. If fuel is running $3.50 a gallon that would buy 17,140 gallons of fuel.

D-

jimh
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Re: Electric motor conversation

Postby jimh » Thu May 13, 2021 1:04 pm

Boat electric propulsion powered by storage batteries is still in fantasy land. Modern batteries need exotic minerals to be mined, refined, processed, and perhaps recycled. The electricity to recharge them comes from coal-fired boilers in generating plants in most instances. Old batteries have to be torn apart, the mineral extracted, then transported to recovery plants to be turned back into useful minerals, which are then hauled back to battery makers. You are essentially moving rocks around.

Petroleum fuel is more efficient; it is a liquid. It flows through pipes for transporting it. The internal combustion engine burns the fuel, releasing carbon dioxide, and trees and sunlight turn that back to oxygen and carbon at no cost. Closed loop recycling.

Using electric motors for boat propulsion is not a new technology. For many decades, going back to the 1940's, ships have been built with electric drive motors, with the electricity generated by diesel engines driving alternators. In a similar manner, railroad locomotives have been using diesel-electric propulsion for over half a century.

The real problems that need to be solved are:
--storing electrical energy in a battery without enormous size, enormous weight, and enormous cost
--quickly recharging the battery when the charge is depleted

Progress in battery technology is occurring.

Creation of a nationwide recharging infrastructure is not likely to occur for decades.

Creation of sufficient electrical energy from non-fossil-fuel sources to provide all the electrical energy for all the electric propulsion motors is not likely to occur for many decades.

Xray51
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Re: Electric motor conversation

Postby Xray51 » Fri May 14, 2021 6:42 pm

Seems like besides the huge cost of $78,000, in light of other disadvantages of this electric product, you might want to have a gasoline auxiliary engine to get you home for when you run out of battery power. Then I guess [the boat propulsion] becomes a hybrid.

I went boating a couple of days ago with my 1994 Montauk 17 and its equally-aged 90-HP Johnson two-stroke-power-cycle engine. The boat ran beautifully. The engine burned a bit less than 10-gallons of Rec90 gasoline while on the water for over six hours, with the engine running most of the time.. The fuel cost was $35--even with the higher prices lately, plus a little oil for the lubrication system.

We are definitely going backwards.

Jefecinco
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Re: Electric motor conversation

Postby Jefecinco » Sat May 15, 2021 9:31 am

Eventually electric propulsion of recreational boats will become reality. For the near future, say five to ten years, electric boat propulsion will be the domain of wealthy "early adopters". I recall the first GPS I bought. It had a small black and white screen with little detail, was inaccurate, lacked anything resembling a nautical chart, and was very expensive. This is not a realistic comparison because a GPS is a very valuable and convenient to use navigational aid but it and adds immeasurably to the safety of boating. I wonder what the price of a large screen Simrad MFD would have been 20 plus years ago. Electric boat propulsion is a gee whiz device best used for showing the owners ability to afford it.
Butch

jimh
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Re: Electric motor conversation

Postby jimh » Sat May 15, 2021 9:52 am

My boat has a 77-gallon fuel tank. My boat engine fuel consumption averages about 4-GPH. The boat can be underway with the gasoline propulsion engine for over 19-hours on one tank. To refill the tank takes about ten minutes. The weight of the fuel is 481-lbs, about the same weight as the engine. As the fuel is consumed the boat becomes lighter.

With electric propulsion the battery or multiple batteries generally will weigh substantially more than the propulsion engine. The underway time is usually limited to less than four hours. Recharging may take 12-hours unless a very rare, very expensive, and very hazardous high-voltage DC fast charger is available--and there are none in place at this moment. The battery weight never changes.

Right now with gasoline engines, getting gasoline on the water at a fuel dock can be awkward and may require waiting in a queue to get to the dock. Imagine what recharging electric propulsion engine batteries on the water would be like if all boats were electrically powered and needed several hours to be recharged. You would have to make an appointment in advance to get to the recharging dock.

A recharging dock capable of handling several boats at once would need a very impressive utility power service. A typical DC fast charging station needs about 60-kiloWatts of energy from the power grid. Let's say you want to be able to charge four boats at once at a marine fast-charging dock: that is 240-kiloWatts of utility power. At a 240-VAC service that is 1,000-Amperes. This is a crazy amount of electrical service. The charging dock would probably have to move up to 480-VAC power and 500-Amperes. And this is all going to be on-the-water?

Talk about marina safety from stray currents in the water--hooking up cables with perhaps 800 to 1,000-Volts to your boat seems just plane nuts. Any stray current in the water, besides being dangerous to swimmers, will also be dangerous to your boat. Galvanic corrosion from stray currents during a hour of fast charging could cause serious damage to any metal underwater part of the boat.

dtmackey
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Re: Electric motor conversation

Postby dtmackey » Mon May 17, 2021 9:17 am

Jefecinco wrote:Eventually electric propulsion of recreational boats will become reality. For the near future, say five to ten years, electric boat propulsion will be the domain of wealthy "early adopters". I recall the first GPS I bought. It had a small black and white screen with little detail, was inaccurate, lacked anything resembling a nautical chart, and was very expensive. This is not a realistic comparison because a GPS is a very valuable and convenient to use navigational aid but it and adds immeasurably to the safety of boating. I wonder what the price of a large screen Simrad MFD would have been 20 plus years ago. Electric boat propulsion is a gee whiz device best used for showing the owners ability to afford it.


The advancement in electronics is from better designs in electronics, software, ASIC chips and the ability to reduce chip size at the same time as increasing power. This was predicted back in 1965 and known as Moore's Law. With battery and energy density, there is no such leapfrog advancement and researchers have spent billions over years with minimal advancement in energy storage. Until there is a radical new technology, electric outboards will remain something that isn't practical for the masses.

Maybe this will be the gamechanger. ;-)

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D-

jimh
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Re: Electric motor conversation

Postby jimh » Mon May 17, 2021 9:31 am

Even electronic circuitry has run into a limit. There are basic factors of Physics that are preventing chip dimensions from getting much smaller or processor speeds from getting much faster; things like the speed of light and the size of atoms are now limitations.