Inboard engines and a changing world

[Lake-Effect]

Originally Posted by jmorrison146

The Green New Dream of charging stations everywhere is a fantasy too. We live in a six-unit condo with an underground garage for 14 cars. One owner had a 220V outlet put in the garage for his electric vehicle. The electrician said that and the existing 220V outlets in the six condos is all the building will handle -- the infrastructure from the street will not support any more 220V outlets.

If the garage 220v outlets are in use overnight for EV charging, when the rest of the condo's big loads (stove, dryer, etc) are most likely off, there's no extra demand on the house service or the grid. This is all very manageable, with timers if necessary.

[GordMay]

Originally Posted by newhaul

do tell
The current 48v brushless dc motors are between 92% and 95% efficient .
Do you have any inside data showing how to improve that level of efficiency?
It is basically against the laws of physics and thermodynamics to get any better .

What can be done to improve motor efficiency?

Fortunately, motor designers have not been limited by your ignorance of physics and thermodynamics, and can minimise losses, by improving the design of features which give rise to the main losses in the motor.

For instance, motor efficiency can be increased by improving the laminations, slot geometry, and slot fill design, and by using smaller cooling fans, and larger conductors.
The greatest losses are the iron losses which occur in the rotor and stator, accounting for about 50% of the total loss. This can be improved by using low-loss steel and thinner laminations.
Copper losses account for about 20%. Using an optimum slot fill design and larger conductors can reduce these.
Bearing friction and windage losses total 23% and can be reduced by using a smaller cooling fan.
Stray losses, which account for 7% of the total, can be reduced by improving the slot geometry.
etc.

[daletournier]

Originally Posted by GordMay

What can be done to improve motor efficiency?

Fortunately, motor designers have not been limited by your ignorance of physics and thermodynamics, and can minimise losses, by improving the design of features which give rise to the main losses in the motor.

For instance, motor efficiency can be increased by improving the laminations, slot geometry, and slot fill design, and by using smaller cooling fans, and larger conductors.
The greatest losses are the iron losses which occur in the rotor and stator, accounting for about 50% of the total loss. This can be improved by using low-loss steel and thinner laminations.
Copper losses account for about 20%. Using an optimum slot fill design and larger conductors can reduce these.
Bearing friction and windage losses total 23% and can be reduced by using a smaller cooling fan.
Stray losses, which account for 7% of the total, can be reduced by improving the slot geometry.
etc.

Genuine question. How much more efficient are electric motors today vs 20 years ago?

[GordMay]

Some excellent insight into EV motors.
The Secrets of Electric Cars and Their Motors: It’s Not All About the Battery, Folks
Car nuts know precious little about the motors in electric cars, yet they’re central to innovation.
➥ https://www.thedrive.com/tech/17505/...-battery-folks

Originally Posted by daletournier

Genuine question. How much more efficient are electric motors today vs 20 years ago?

This article should give you some insight into different motor efficiency standards. Prior to the 1980s (when higher efficiency motors were first introduced), all motors were similar to “Standard Efficiency”.
See ➥ https://www.ny-engineers.com/blog/ne...iciency-motors

[Reefmagnet]

Originally Posted by Lake-Effect

If the garage 220v outlets are in use overnight for EV charging, when the rest of the condo's big loads (stove, dryer, etc) are most likely off, there's no extra demand on the house service or the grid. This is all very manageable, with timers if necessary.

That's not how code compliant wiring is done.

[Reefmagnet]

Originally Posted by GordMay

Some excellent insight into EV motors.
The Secrets of Electric Cars and Their Motors: It’s Not All About the Battery, Folks
Car nuts know precious little about the motors in electric cars, yet they’re central to innovation.
➥ https://www.thedrive.com/tech/17505/...-battery-folks


This article should give you some insight into different motor efficiency standards. Prior to the 1980s (when higher efficiency motors were first introduced), all motors were similar to “Standard Efficiency”.
See ➥ https://www.ny-engineers.com/blog/ne...iciency-motors

It's not about just the motor. Losses are also present in the speed and torque regulation circuitry. Even lifepo4 has reduced capacity at high loads.

Then there's prop and hull fouling, sea state, head winds and opposing tide to contend with on a boat that will effect speed and range enough to make the whole idea of electric drive without backup nothing more than a pipe dream for anything other than marina queening, YouTube infotainment or protected waters sailing.

[newhaul]

Originally Posted by GordMay

What can be done to improve motor efficiency?

Fortunately, motor designers have not been limited by your ignorance of physics and thermodynamics, and can minimise losses, by improving the design of features which give rise to the main losses in the motor.

For instance, motor efficiency can be increased by improving the laminations, slot geometry, and slot fill design, and by using smaller cooling fans, and larger conductors.
The greatest losses are the iron losses which occur in the rotor and stator, accounting for about 50% of the total loss. This can be improved by using low-loss steel and thinner laminations.
Copper losses account for about 20%. Using an optimum slot fill design and larger conductors can reduce these.
Bearing friction and windage losses total 23% and can be reduced by using a smaller cooling fan.
Stray losses, which account for 7% of the total, can be reduced by improving the slot geometry.
etc.

sorry but don't matter how you slice it or hype it you won't get better than 96% efficiency out of an electric propulsion setup .
The particular volcano motor for my boat ( if I were doing that conversion) is 92% efficiency .
5.5HP 48V High Power Brushless DC Motors from China BLDC Motor Manufacture

[GordMay]

Originally Posted by newhaul

sorry but don't matter how you slice it or hype it you won't get better than 96% efficiency ...

ABB recently set the world record for electrical synchronous motor efficiency. During factory acceptance tests (FATs) carried out with the customer present, we recorded a result of 99.05% full load efficiency on a 44 megawatt, 6-pole, synchronous motor. The motor was included in a contract for six motors of the same design and they all had test results above 99% efficiency. The contract had guaranteed an efficiency of 98.80%, meaning that the efficiency on this motor is 0.25% greater than anticipated.
A typical efficiency for this type of synchronous motor is approximately 98.2 to 98.8%.
➥ https://www.abb-conversations.com/20...gy-efficiency/

[newhaul]

Originally Posted by GordMay

ABB recently set the world record for electrical synchronous motor efficiency. During factory acceptance tests (FATs) carried out with the customer present, we recorded a result of 99.05% full load efficiency on a 44 megawatt, 6-pole, synchronous motor. The motor was included in a contract for six motors of the same design and they all had test results above 99% efficiency. The contract had guaranteed an efficiency of 98.80%, meaning that the efficiency on this motor is 0.25% greater than anticipated.
A typical efficiency for this type of synchronous motor is approximately 98.2 to 98.8%.
➥ https://www.abb-conversations.com/20...gy-efficiency/

44 megawatt. That's about 40k pounds of motor .

Yes they get great efficiency at huge sizes but scale it to the 25 pound brushless motor to drive a 30 to 36 ft sailboat . Best you will do is 92% efficiency ( best I can find that is )
brushless permanent and magnet 5kw motor . ( Gives regenerative capability) .
The big issue is The energy density 100ah 48v Lfp is 25.2 kg for sinopoly bare cells . Now you increase that density to 200ah per 25 kg battery weight and you are in the ballpark .

[fred4936]

About 8 years ago I converted our Tartan 27-2 to electric after giving up on the diesel it came with. It has worked out very well for us. For cruising on Great South Bay and even beyond, I think it is ideal. We have the boat on the market now, because we bought a bigger boat, a Pearson 34-2. I would like to go hybrid on the new boat eventually. Electric works well, but it does not serve every need, like anything else. Yes, I must have a thing for -2!

[StuM]

Originally Posted by newhaul

The big issue is The energy density 100ah 48v Lfp is 25.2 kg for sinopoly bare cells . Now you increase that density to 200ah per 25 kg battery weight and you are in the ballpark .

100ah @ 48V in 25.2 Kg = 190 Wh/kg


So 200 Ah would be 380 Wh/kg. How does nearly three times that - 1000Wh/kg sound?


Don't hold your breathe, but good thing may be coming in a few years time.

https://www.theengineer.co.uk/innoli...-breakthrough/

and an interview with Innolith's CEO and Chief Engineer with more info here:
https://about.bnef.com/blog/innolith...ithium-ion-qa/

[valhalla360]

Originally Posted by Lake-Effect

There's no denying the simplicity and reliability of a basic diesel turning a propshaft, but at least in theory, an ICE generator, battery-bank and electric motor should be more efficient. ICEs are most efficient when they're optimised for running at one speed and turning a steady load (eg a generator), and electric motors are efficient and capable over a wider range of speeds and loads.

This (minus the batteries) is how most diesel locomotives and many big cruiseliners are powered. I don't know whether this sort of system yields enough efficiency yet at "sailboat" size to justify the complexity and cost.

Your theory holds up if you put a 500hp diesel in a 40ft monohull sailboat.

Assuming things are operating properly and the prop & transmission are appropriate, a 40hp diesel in a 40ft monohull is going to be operating pretty darn close to peak efficiency. Your average cruising monohull has the throttle set to cruising speed and it sits there for hours at a time when motoring (if you only use it to get in and out of the marina, you are using so little fuel that it's purely an academic question of no real use in the real world).

When you add the losses converting generator mechanical energy to electricity and back (possibly including a battery storage conversion), a direct driver diesel will typically be more efficient.

Locomotives and ships using diesel electric have almost nothing to do with efficiency but the electric portion acts as a transmission since a mechanical transmission is very problematic for such high power scenarios.

[Pete7]

What I don't understand is why EV cars don't have a 400-600w of solar on the roof. Won't make much difference if the vehicle is used on a long journey, but for around town short trips were the car is parked up all day at work that would be free power topping up the battery system.

Pete

[GordMay]

Originally Posted by Pete7

What I don't understand is why EV cars don't have a 400-600w of solar on the roof ...

➥ https://qz.com/1482588/why-teslas-do...e-solar-roofs/
➥ https://www.solyndra.com/why-dont-el...s-on-the-roof/
➥ https://www.forbes.com/sites/bradtem.../#308ab8c1537e

[Pete7]

From the Telsa article:

The most efficient production electric vehicles today (probably the Hyundai Ioniq and the Tesla Mod 3) would only be able to travel 2–4 miles on that amount of electricity…in an hour. Most people could walk faster.

Financially, the cost of the panels and electronics, R&D and assembly would never pay for itself in the life of the vehicle, compared to charging from the wall in your garage.

Just strikes me if a car was stationary for 8 hours during the day then it starts to stack up. Costs of R&D and assembly, think they miss the point, it wouldn't need plugging in for short trips. Of course Telsa wouldn't then sell you as much electricity

Pete