Electric Drive: Who uses it?

[Dockhead]

Originally Posted by ctsbillc

The energy density of good Lithium batteries is about one tenth that of Diesel, so be prepared to install a lot of batteries at huge cost if you want a practical range. Lithium batteries also have an unfortunate tendency to immolate themselves. It's bad enough watching your Tesla burn to the ground, but much worse on an open ocean.

Actually I thinks it's 1/150, not 1/10. 0.3MJ/kg vs 45.

So it would take something like 100 tonnes (!) of li-ion batts to store as much energy as I have in my tank.

[ctsbillc]

Torqeedo uses Lithium Ion batteries, as an example of maritime use. On their larger electric outboards, they use BMW's car Li Ion packs.


Where you won't find Lithium Ion at sea is submarines. Latest submarine packs are thin plate pure lead (TPPL). The improved capacity of Lithium Ion batteries would have astonishing gains for diesel Electric submarines. The subs I'm involved with are 2,500 tonnes, and have a 9,000 Amp/hour battery pack running at 600 V - takes up a considerable part of the boat.



When my boat AGM batteries die, I'll replace with TPPL. They're twice the cost of AGM, but have no discharge limitations (use almost all the rated capacity, not 50%), longer life, and better charge acceptance rate, making them much more efficient. Still 1/5th the cost of Lithium.


Here's a presentation on the hazards of Lithium Phosphate. They are better than Lithium Ion, but not immune from catastrophic failure. https://www.slideshare.net/lewisglar...aysaug-21-2013

[a64pilot]

Originally Posted by john61ct

Lithium is an umbrella term for many different chemistries with very widely differing susceptibilities to thermal runaway.

LFP is very safe, and widely used in marine applications, but mostly House banks.

The energy density is the catch of course, that is why Li-ion and Li-PO are used in things like automobiles and high end Scuba Scooters, LFP is safer, but about twice the weight for the same power.

Where all these discussions go eventually is simple physics, it takes X amount of power to move a boat X number of miles, which is X number of thousands of lbs and XX number tens of thousands of dollars of batteries.
Usually environmental concerns are the driver for these desires, but the environmental concerns of hundreds or thousands of lbs of batteries is never discussed, nor is the fact that the energy the store is very likely generated by the burning of fossil fuel.
That is what I think is interesting with the electric car advocates, they act as if the power from the wall just exists in the wall and is unlimited.

What Boat Alexandra has done is seemingly really the best answer from a money perspective and an environmental concern, that is scull and sail.

If someone put half the money and work into making the boat sail better as they do with these electric conversions, it may be that the electric conversion isn’t as necessary?

Sorry, guess I’m a little grumpy this morning

[Dockhead]

Originally Posted by a64pilot

. . . If someone put half the money and work into making the boat sail better as they do with these electric conversions, it may be that the electric conversion isn’t as necessary?. . .

I'm here to tell you -- having just motored against the wind for 250 miles -- that unless you are just sailing around the bay on weekends, or permanently retired and just drifting around the world wherever the wind blows you, you need power, if you plan to ever get anywhere, even if you have a certain amount of flexiblity in your schedule.

I'm on my way to the Arctic with the whole summer to do it. The first leg -- UK South Coast to the Orkneys -- should have been easy peasy beam reach in the prevailing winds. But instead a perverted East (in the Channel) and N (in the North Sea) flow set in and has lasted for TWO WEEKS. Wind right on the nose, and too light for effective tacking, plus in many areas there isn't even room to tack. So we motored for 250 miles and only just now got free of East Anglia where we will be able to tack as we need to in the wider expanse of the Northern North Sea.

To each his own, but MY ideal cruising boat will need to have very good efficient motoring capability, able to get considerable distances upwind under power.

I spent a ton of money and effort getting my boat in condition to be able to get upwind at all (as compared to most cruising boats) -- carbon sails, blade jib, special rigging, got rid of a lot of windage, etc etc etc . It helps a lot but there are still a great variety of conditions where you either wait or use the motor.

This is why electric won't work for a lot of cruisers, but could be great for day sailors.

[a64pilot]

Dock, welcome to my world.
Regardless of forecasted conditions, whenever we go somewhere within 24 hours, the wind is coming from our destination.

[Jim Cate]

I believe that nearly all traditional fishing cultures have a folk saying that goes "the wind always blows from the bow".

Possibly there is a reason for this...

Jim

[Wayfarer1008]

Just think a wind turbine powered boat. the blades can turn creating energy to turn the propeller. What a classic green energy alternative

[a64pilot]

Originally Posted by Wayfarer1008

Just think a wind turbine powered boat. the blades can turn creating energy to turn the propeller. What a classic green energy alternative

There have been a couple of those built, one had a regular windmill, and another I have seen pictures of had a horizontal windmill, which seemed to at least look more practical.
Apparently neither Sail as well as an old fashioned sail boat though.
https://www.treehugger.com/renewable...-the-wind.html

[alickn]

This might be of interest... In a previous life BMCP (before my current partner) I was living aboard a Prout Snowgoose Elite by the name of Liberator. Whilst in the process of replacing an old, worn out 30hp Yanmar inboard, I looked at several generating options for those days when I fully expected to not be alongside a convenient electric hookup in a marina. I discounted the suitcase type, as there was nowhere convenient on the centreline to position one. Another option had a generator fixed around the flywheel of an inboard diesel, but the accepted wisdom/gossip/scuttlebutt in my marina was that they could be explosively unreliable.

I then looked at an arrangement from Hybrid Marine who are based on the Isle of Wight. Their system uses a lynch motor fitted to the aft end of a Beta 30hp diesel which could deliver @13hp to the Sillette leg via a toothed belt from a 48v battery bank. (They sell almost all their production to the narrowboat market, so the concept is proven, even if this was the first time they had put the hybrid into a catamaran). It would be controlled through a clever box of gubbins/electronics using the existing throttle lever from the inboard diesel. Via a small control panel, I could, whilst running the engine when cruising or at anchor, also use the lynch motor as a 5KvA generator to put a charge into the battery bank.

Total cost was roughly £2K more than the other options, and this is what I went for, for the following reason. It gave me a get out of jail card that the other options didn't, as I would have a second form of motive power. It also offered greater generating output through some cunningly designed control circuitry. So should I be motoring in windless conditions and the diesel failed, I could use the hybrid to get me out of trouble (realistically, it wouldn't get me off a lee shore in the face of a Force 9 gale, but then neither would a 30hp diesel). The other options would see me frantically sending out mayday calls whilst the tide carried me onto the rocks, consoled only by the thought that I had saved myself £2K.

I had to fit 4 x 180AH 12v Odessy AGM batteries in series to provide the oomph, and I obtained a 12v domestic supply via a 48v to 12v converter. It generated power efficiently and faultlessly whenever asked to do so on 'Pirate Grandad's Epic Voyage' around Great Britain in 2014.

Only once was it called upon to drive the boat, and it did so extremely well. I had booked a pilot to work the locks on the Crinan Canal for me, but within 30 seconds of setting off to meet the deadline at the first lock, Liberator's diesel overheated. A blocked cooling water filter (very odd, as it had been clear when last inspected - what - only two years previously). Engaging the electric drive, I got to the lock in plenty of time, making slightly over three knots through the still canal waters.

All the way through the next twelve locks I checked the Victron battery monitor, and all was well. With one manned lock to go, I moored at the first pontoon with an electric point I came to. The batteries were still giving full power, so I reversed the drive, moored and plugged in the shore lead. When I checked the battery monitor, it told me I had 2% remaining in the battery bank. I reckoned I had about 9 miles of calm water progress under my belt, and as a hybrid unit, with the ability to give emergency power when required, I would recommend it. But next time I have to replace an engine in a Snowgoose, I would fit a 45hp unit, that could deliver substantially better consumption than 5 litres per hour at 2750rpm for 5 knots, which was all I could get from 30hp.

[hzcruiser]

Originally Posted by Dockhead

Actually I thinks it's 1/150, not 1/10. 0.3MJ/kg vs 45.

So it would take something like 100 tonnes (!) of li-ion batts to store as much energy as I have in my tank.

Taking into account the efficiency of an ICE compared to electric would likely half your req'ts to a "more manageable" 50 tonnes, wouldn't it?

[Dockhead]

Originally Posted by hzcruiser

Taking into account the efficiency of an ICE compared to electric would likely half your req'ts to a "more manageable" 50 tonnes, wouldn't it?

Yes -- fair enough. I forgot all about that bit.

But still that's a far cry from 1/10. I guess taking into consideration thermal efficiency maybe 1/100?

[Wayfarer1008]

The other problem is lithium ion batteries if they get exposed to salt water do not short out but actually explode. Keep Your bilge dry !!!!

[a64pilot]

Originally Posted by Dockhead

Yes -- fair enough. I forgot all about that bit.

But still that's a far cry from 1/10. I guess taking into consideration thermal efficiency maybe 1/100?

A very good electric motor run at it’s efficiency high point which I think is usually about 75% of rated power can be up to as much as three times as efficient as a poor internal combustion motor.
So I’d say that electric is twice as efficient and think it a fair statement.
Of course that is ignoring efficiencies In charging batteries, delivering the power over a grid etc.
As always the answer isn’t simple.

[hzcruiser]

Originally Posted by Dockhead

Yes -- fair enough. I forgot all about that bit.

Of course. That was tongue in cheek anyway.



The higher the energy density we get with batts, the more scaremongering we'll see about them catching fire and blowing up at the most inopportune time anyway...

[hzcruiser]

Originally Posted by ctsbillc

Torqeedo uses Lithium Ion batteries, as an example of maritime use. On their larger electric outboards, they use BMW's car Li Ion packs.

Yes, Li-Ion, not LFPs.

Originally Posted by ctsbillc

When my boat AGM batteries die, I'll replace with TPPL. They're twice the cost of AGM, but have no discharge limitations (use almost all the rated capacity, not 50%), longer life, and better charge acceptance rate, making them much more efficient. Still 1/5th the cost of Lithium.

I'm the last one trying to convince you otherwise, so please, let us know once you migrated to TPPL (thin plate pure lead). What are the real costs and weight per kWh?

It's not easy to find those batts, as they seem to be fairly new (from 2014?) and Trojan comments that "they will not last as long as thick plate pure lead technology" here:

https://www.google.com.au/url?sa=t&r...rehryU8NsbKeHY


Granted, they want to sell their thick plate batts, as it seems that NorthStar has patented TPPL ?
Being as it is, I get hugely different prices from AUD 300-700 per kWh, their weight being about 25kg/kWh:

SMS-AGM8DK 12V 228 Ah AUD 1931
NSB100FT RED 12V 100 Ah AUD 360

source:

https://batteryspecialists.com.au/ba...batteries.html

Compared to 100Ah LFP (including BMS): AUD 1350 /kWh and 4.1kg/kWh

https://www.lfp.net.au/product-page/...-compress-pack


Hence, LFPs in this example are 1.9 to 4.5 times more expensive yet the TPPLs weigh 6 times more per kWh.

Sounds pretty bad for the LFPs on the price front, doesn't it?

Only they are rated at 2000 cycles compared 400 cycles for TTPL? That factor of 5 would make them immediately cheaper over their lifetime. Yet, even if they only lasted double the cycles compared to TPPL, I much prefer saving all that weight (and my back) at price parity.

source:
https://www.upsbatterycenter.com/blo...s-limitations/

Originally Posted by ctsbillc

Here's a presentation on the hazards of Lithium Phosphate. They are better than Lithium Ion, but not immune from catastrophic failure. https://www.slideshare.net/lewisglar...aysaug-21-2013

Err, I actually took the time to look at the preso, being a public holiday here in Oz, and yes, it is shocking!



Catchy headline about LFPs being "another fool's paradise" presented by a company who wants to get their competing battery technology on the market!? Hmm, get the salt shaker ready...


It is honestly one the worst presos I've ever seen. 35 pages, where in the first 30 they keep drifting into Li-Ion batts stories, very little about LFP. The photos on those first 30 pages are, except for one, all clearly Li-Ion devices that caught fire. The one I'm not sure about is a generic batt engulfed in smoke.


On the last 4 pages they present:


- one LFP batt allegedly catching fire in a university lab. There was an explosion asto which one bystander commented that it "could have been an aerosol can, we just don't know"


- two slides about burning race cars using LFPs to store energy for regenerative braking. Hmm... I wonder if they used the batts within their specs?


- the last one about an Audi R8 catching fire because the owner wanted a sound system that could deliver more oomph than any of his buddies' pimped up cars. If that is you, then yes, please stay away from LFP!


By the way, the company (Lattice Energy) that cobbled together this pile of bull dust preso wants to sell you.... wait:

a "low-energy nuclear reaction" energy storage system. Nuff said.