Battery power, the way forward ?

In a moment of idle speculation, I once thought that, were I seriously wealthy, I'd talk to Southerly about building a boat with a half-weight ballast & grounding shoe, replacing the weight with lithium cells. Instead of a normal engine, there's be an azipod ahead of each rudder, giving mobo manoeuvrability at low speed. Power would be provided by solar panels and a generator with enough umph to make reasonable progress, assisted by the batteries when extra is needed. Most of the time, solar power through the week would provide enough charge for a weekend's sailing and you wouldn't need the generator unless motoring a long way.

Unfortunately, I reckon I wouldn't have much change from £1M, but that's for a prototype. I still think that something similar could be the future of sailing once prices come down far enough.
 
Stemar,

if you said Ovni instead of Southerly you might have a potential lottery taker here, then it would probably be cheaper and better to do it with a Rustler and forget the azipods.
 
Graham376 said:
Electric tourist boats (based on moorings) carrying up to around 10 people seem to work OK with 4 large solar panels but I don't know for how many hours in service. A guy I was speaking to recently was looking at converting his Westerly 33 to electric and he says the cost is about the same a new diesel engine but, only 15 hours range which may well be OK for weekend sailors but not for long passages when extended power range may be necessary - we spent 40 hours on engine during one Biscay crossing.
Click to expand...

15 Hours Range? Not a chance. This has been done to death .. but, let's do it again.

Assume a typical 30hp Diesel .. lets go for half that ... 15hp actual output.

15hp is a little over 11kw ... so at 12V that would equal 900 odd amps .. so 15 hours would need 14,000 amp hours ... or if you prefer 165 kWh ... a Tesla replacment 60kWh battery is currently about $24,000 (June 2019 prices) so 3 of those or about $73,000 worth, will give you 15 hours at 15hp level.


And thats just the USABLE amp hours, you would probably need more than that as you cannot get all of it out.

Someone earlier was posting "real world" figures from their 330W solar installation .. roughly 1.5kwh a day ... so a 1kw solar install might manage 4.5kwh a day, lets be generous and say 5kwh ... which with 100% perfect storage would give you ... 8 minutes runnign at the 15hp level ...

Useless for boats. Great for cars with easy access to high power charging points, but until they start fitting them to buoys half way across the channel, totally unsuitable. I'll stick with a can of diesel, cheap, reliable and at least 50 times the energy storage density of batteries, and "recharged" in a minute.
 
Last edited:
Graham376 said:
I don't know his specification other than he says he has a source for lithium batteries at a good price.
Click to expand...

Shh, let the naysayer have his moment in the limelight, makes him feel special to be running a motorboat. :). All of this, "Oh it's so much better to use diesel" makes me think the diesel fuel tax is nowhere near high enough (increase of say...50x?)
 
Luminescent said:
Shh, let the naysayer have his moment in the limelight, makes him feel special to be running a motorboat. :). All of this, "Oh it's so much better to use diesel" makes me think the diesel fuel tax is nowhere near high enough (increase of say...50x?)
Click to expand...

I don't have a motoroboat. It's not primarily to do with the cost either, although it is a factor.

The day they produce an electric power system that has the same range as the small fuel tank on my yacht for a similar weight, I'm all in. They are not even close yet, and I doubt they will be in my lifetime. If you want to rip your engine out and fit an electric motor, you go right ahead.
 
Graham376 said:
I don't know his specification other than he says he has a source for lithium batteries at a good price.
Click to expand...

But as pointed out above, youd need the equivalent of 3 Tesla 60kwh packs (thats 3 car loads) to get that 15 hours at 15hp ... regardless of the price, that's an awful lot of batteries and complication to carry around, even if you can get them at a good price.

Don't get me wrong, they certainly do have an application, especially in cars, local delivery vehicles, personal transport (I forsee the idea of using a 4 person sized car when a one or two person sized unit would be appropriate becoming the norm.) We actually need more of them to soak up the wind power that is generated out of peak hours, where most of it simply goes to waste.

For cars, with a network of recharge points, with short distances, the ability simply park anywhere etc they make perfect sense. For most boats, they do not, as the amount of distance needed for them to be useful and the lack of recharging points at sea simply make it a non starter. For my sailing, I need that engine as a backup, as a get-out-of-jail option when the wind dies or is badly against me, and I need to get to port before the crap sets in. At that point, I just need x hours of good solid reliable diesel power, with a full tank and reliable engine that will go on for as long as I need it to. There is simply no space for the amount of battery storage that would be needed to replicate that 120 litre tank of fuel.

I can see they would be great for things like water-taxis, where a high rate charger could even be used as they docked to board passengers, or drop in battery units ... but for sea going yachts, where space is already at a premium, nope.
 
rszemeti said:
I don't have a motoroboat. It's not primarily to do with the cost either, although it is a factor.

The day they produce an electric power system that has the same range as the small fuel tank on my yacht for a similar weight, I'm all in. They are not even close yet, and I doubt they will be in my lifetime. If you want to rip your engine out and fit an electric motor, you go right ahead.
Click to expand...

Dont be so sure...

I am a fan of Bloodhound SSC, the fantastic attempt to build a 1,000mph car. One part of the system is a pump to send oxidiser (High Test Peroxide) to the hybrid rocket motor. The original deign required an 8 cylinder RS Cosworth engine to turn the pump. Due to several setbacks and funding delays technology has overtaken that part. Now you can buy off the shelf electric motors and batteries to do the same job!
Sure this is the complete opposite of boat requirements, very high power for a short time vs low power for ages and ages, but that change was less than a decade.


Bloodhound SSC cool fact: If successful it will be the fastest transport at zero altitude, beating any aeroplane yet made.
 
Oh dear !

I thought the Mercedes AA class spoof video was amusing and worth sharing for a smile.

I knew some of you like to argue for the sake of it, but this has to be a new level LOL

Even funnier than the You Tube vid ;)
 
Last edited:
PaulRainbow said:
Oh dear !

I thought the Mercedes AA class spoof video was amusing and worth sharing for a smile.

I knew some of you like to argue for the sake of it, but this has to be a new level LOL

Even funnier the the You Tube vid ;)
Click to expand...
Nice troll. You got me. I thought you were just linking to a dreary new electric car review, so I didn’t watch it.
 
The Danes have just built a new 100% electric ferry - her route is 22 miles, and she can carry 200 passengers and 30 vehicles. She has two 750 kw propulsion motors, and two 250 kw thrusters.
And 4.3MWh of battery capacity.
They 'plug in' during each turnaround, and this seems to be enough to keep them topped up.

https://www.maritime-executive.com/article/electric-ferry-makes-record-voyage-in-denmark

https://www.electrive.com/2019/08/16/powerful-electric-ferry-ellen-takes-to-the-sea/

https://www.forbes.com/sites/jamese...has-completed-its-maiden-voyage/#3ab5a72e556a

Edit - I just saw this article in my daily email from the Boat Test folk. They mention hybrid systems and all electric propulsion.
https://www.boattest.com/view-news/6545_how-to-go-green-now
 
Last edited:
Zing said:
It’s a total non starter unless you can get to mains charging regularly. Batteries in lithium are 50 times less energy dense than diesel, so work out how much diesel you would need in a boat then multiply that diesel weight by 50 and if you can make it work go for it. For an ocean capable yacht it is unworkable. Volumetrically it also difficult and unworkable probably, needing about 20 times the space of diesel. It is also a bad idea to pay for energy storage you will only use once a year if that.

There’s an old and cheap, lightweight and well proven renewable energy that is much better - sail power.
Click to expand...

I don't claim to be expert but aren't you forgetting that a car motor uses an enormous amount of the fuel to generate heat, noise etc as well as motion?

" A lithium-ion battery pack has about 0.3 MJ/kg and about 0.4 MJ/liter (Chevy VOLT). Gasoline thus has about 100 times the energy density of a lithium-ion battery. ... The efficiency of an internal combustion engine in converting the energy stored in gasoline to making the car move is typically 15 percent (EPA 2012)

The car/boat would be a lot lighter and it would not need a gearbox, differential etc and the car chassis could be lighter. The energy used in stopping the vehicle could be used to generate power.
 
Last edited:
As battery technology improves I'm sure we will all raise our eyebrows at its uses

Why the age of electric flight is finally upon us
By Tim Bowler BBC News, Le Bourget, Paris
3 July 2019
https://www.bbc.com/news/business-48630656

_107472398_uktwyjna.jpg

Advances point the way to smaller, safer batteries - ScienceDaily

" Mar 18, 2019 - New research advances the design of solid-state batteries, a technology that is inherently safer and more energy-dense than today's lithium-ion batteries, which ..
 (Science Daily)
 
Last edited:
You must log in or register to reply here.

Other threads that may be of interest

N
Integral Battery Electric Outboards… with MORE POWER!
Replies
11
Views
744
ontheplane
O

Share this page

Top