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Electric Drive H28


DrWatson

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Re the batteries ( I didnt look at the links so might be a silly question ) but are these batteries able to be discharged down deep without damage?

 

If you _need_ 200Ah of capacity to do what you want, with lead acids you really want at an absolute minimum 400Ah of battery capacity to avoid damage to the bank, and 800ah, to get a good long lifespan from the batteries. Makes the weight of a small diesel electric setup look insignificant maybe?

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These batteries would be great for this http://www.aasolar.co.nz/AA%20Solar%20L ... eries.html

 

 

Holy hemorrhoids batman, I just checked the price on those batteries - $5,000 for 500Ah at 12V!! - about 5 times the initial cost of lead acid.

 

I think I’ll wait till this stuff gets cheaper

 

Yeah but you only get 500-600 cycles our of a lead acid deep cycle battery assuming a depth of discharge (DOD) of 50%. You are meant to get 5000 cycles out of a LiFePO4 battery with a DOD of 80% i.e. 10 x the cycles for 5 x the price. You do need to factor in an upgrade to charging system if you want to maximise your benefits so its not quite that simple.

 

Also from what I understand the LiFePO4 batteries will accept near 100% charge up until full unlike lead acid batteries that tapper off. Your typical cruiser who is trying to maximise the life of his/her deep cycle battery will only use 30% of its capacity (50%-80% range) whereas the Lithium batteries can use up to 80% i.e. 50% more usable power for the same rated battery. What's better is that they generally are lighter than your nomal lead acid battery.

 

KM had a slightly less technical thread somewhere around on these batteries.

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Have a look at the link to AA Solar. Lots of stuff there and comparisons to lead acid.

Being able to charge at full speed would be great when you have 5 kilowatts coming out of the dc motor when running the diesel. I guess 100 amps at 48 volts so won't take long to re charge. Also with this amount of power available running the fridge won't be a big deal, maybe even air conditioner! Different world with this amount of power aboard.

The Lithium batteries are a bit less than 3 times the cost of sealed lead acid from AA Solar.

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Its a 100 amp 3.2 volt. So a bit more than $1000 per 100 amp hour at 12.8 volts. Saves quite a lot of weight and space! They have a hybrid system as well.

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Just found this on the Enertec website (Mastervolt)...."For six to eight hours sailing, you require 4.6 x kW capacity in kWh. Example: 4.6 x 3.5 kW = 16.1 kWh; this is the capacity required for six to eight hours sailing."

So for a 5 kilowatt motor......4.6 x 5 = 23kwh which at 48 volts is 23000 / 48 = 479 amp hours for 6 to 8 hours motoring.

With a hybrid setup I'd be happy with around 1 hours motoring because thats mostly what would be needed to get into and out of a harbour. So 480 / 6 = 80 amp hours. So 80 amp hours at 48 volts is 320 amp hours at 12 volts which is a bit light on for the house. Probably be ok if we went with the Lithium batteries.

With this setup one could motor electric sail say in light air or in a big swell and light air using very little throttle for considerably longer periods. This is one of the main attractions of electric drive for me.

http://www.mastervolt.com/marine/products/e-propulsion/

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So it is one hell of a lot of money to spend to get in and out of a Marina. You would be better off with a small outboard you could then remove and stow in a locker. For me (but remember we have a big Motor sailor) the engine is an important piece of equipment.

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Well $15 to $20 grand for a diesel is a big reach also. I understand your "floating palace" :thumbup: may be not suited to electric drive. Where I see a large advantage is in sailing in light winds with a bit of assist from the engine. In my current situation we could re charge the batteries with shore power and rarely need to use the diesel, though I reckon it would need to be run fairly regularly.

This is an interesting development......http://www.gizmag.com/mecc-bio-methanol ... der/23462/

maybe we can fill these tanks from a service station. We need something like this to make electric drive alone suitable for long range cruising.

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The more I read the more I am convinced the day of cheap fossil fuels is over and never coming back. Thus being able to regenerate under sail makes lots of sense.

Remember Wheels that is pretty much a one off cost vs buying diesel, oil , filters, fan belts, repairing pumps, replacing impellers ....... for a very long time.

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You'll like this Ogre from EV Concepts.....

"With good winds the system can regenerate power through the spinning prop. The regenerating system uses the power in the pop shaft to spin the electric motor to recharge the batteries. It takes about twice as long to recharge the batteries under sail as it does to drain them while under power. So motoring out of the harbor, sailing for four hours, then motoring back in for an hour would result in no overall change in the charge in the batteries. "

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There, that's twice as good as we were quoted earlier. The fun thing is that a full time live aboard is probably better suited to this than the weekend warrior (no need to be back Monday morning). But it will require a shift in thinking, arriving with the "fuel tanks" full, and leaving when they are empty.

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What I haven't been able to find is whether the shaft stops spinning when the batteries are fully charged??? Although problem solved by the suggestion above of a folding prop and a separate towed water generator.

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Remember Wheels that is pretty much a one off cost vs buying diesel
I wish it was, but you get ruffly about 1000 charges with current lithium technology. With the Prius cars, they seem to get about 7yrs out of their banks. At current costs of 12K for a bank, then that's a hell of a lot of diesel. Sadly, Fossil fuel is still cheap and will remain so I think. It is not running out like many would have you believe. The cost is being set by speculators, not those that suck it out of the ground. Plus, don't fool yourself in thinking that a Lithium battery is "greener" than fossil fuel. It's cost is because of the enormous amount that goes into making it in the first place. The material passes through 5 different processes, in 5 different countries before it ends up as a battery in your boat. Then you have to dispose of it when it is shot.
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Fossil fuel is still cheap and will remain so I think. It is not running out like many would have you believe.

 

 

Ok, there we have to agree to disagree.

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If a genny is aboard you then don't need a huge set of batteries. Enough to get into and out of a harbour at 5 knots would be fine then if you needed to go further start the genny. Even 200 amp hours at 48 volts gives 800 amp hours at 12 volts so the house needs are well covered. I'm now thinking 100 amp hours at 48 volts would be enough. These batteries would charge in an hour on shore power. I estimate the trip from my berth out to sea, about 20 minutes, would use around 24 amps at 5 knots. A lot less if we did 3 knots.

I agree Ogre, fuel will continue to rise in cost, especially if they have a war in the middle east.

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From an owner with electric drive

 

Let's put an electric drive maritime myth down...

 

More than time to face up to some problems, who says there's no voter fraud (but you might want to check out the voting while dead culprit), and George R. R. Martin makes a point...

 

I had a couple of readers who took exception with my pointing out the other day that electric propulsion works out at being quite a bit less expensive in a repair/replacement situation... Sadly, the maritime myth of electric propulsion being MORE expensive than ICE just won't go away.

 

The thing to keep in mind is that electric propulsion is a very simple system and there is very little to go wrong. You could fry the motor, destroy the controller, have a belt fail, or if really talented in the mayhem department, you could rip the throttle off and destroy it in the process.

 

Not a lot to go wrong but, just in case, here are some numbers for the system on "So It Goes" (an Electric Yacht drive if anyone is interested)...

 

The most likely repair, a stretched or broken belt, would cost you somewhere south of $25. Not a lot of money (and I really should buy an extra one for just in case).

 

A replacement motor would cost between $600-$800 and is small and light enough to actually consider buying one as a spare.

 

The brain of the system is the controller and a replacement would run around $800. Just for the record, we do have a spare controller as it is the one part we'd expect to find difficult to get repaired or replace in the boonies.

 

The throttle is just a potentiometer so replacement is anywhere from a couple of dollars to around $100 for something that looks like what we expect a boat throttle to look like.

 

Those are replacement costs and as most of these items can actually be repaired, repair costs could be quite a lot less...

 

So, even if we had to replace ALL of the various parts of our system that could go wrong, we'd only be out of pocket (by my calculation) somewhere around $1630 which, I think you'll all agree, is quite a bit less than replacing all the major bits on an ICE system.

 

I really should also point out that an engine-less cruiser does not have to worry at all about the cost of replacing systems or repairs which might be something to keep in mind.

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Remember Wheels that is pretty much a one off cost vs buying diesel
I wish it was, but you get ruffly about 1000 charges with current lithium technology.

 

I think that figure you are quoting might be a bit misleading. From the numbers I have read about, you get roughly about 1000 cycles (charges) if you do a 1:1 replacement of lead acid to Lithium leaving the original style charger in place. If you install the correct battery charging system you should get between 5000 and 7000 cycles.

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Ok ok now that's enough of this silly talk, we must be able to do a costing

 

Hippopotamusly speaking I am building a new 40 ft cruiser, the hull is finished but the internal fit out hasn't started.

I'm going to own this boat for 30 years so I will average out the costs

ICE

 

40hp diesal with sail drive prop and controls. $20k~

Fuel tank, exhaust system, house and engine batteries,smart charger, fuel lines etc $10k~

At year 15 to 18 this unit will need a rebuild or replace so another $20 k

I will do 200 engine hours per year at 2.5ltrs per hour so 500 ltrs at $2/ltr plus I will do all the servicing myself but oil and filters etc will be $200 so annual running cost of $1200/annum

I will have 2 house and 1 engine batteries and will replace these on average every 5 years at $100 per year

I've probably been a little light but close enough ?

 

At a rough count I make that just a tad under 3k per year

 

Now who wants to do the same for electric drive system ?

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A good FLA house bank with a good charging system, and properly managed, should easily give you 10yrs or even more. My batteries have a 10 warranty for a starter.

I will leave the electric costing to someone else. But if it is possible to get 5000 or more cycles from LiFe with proper charging, then lets factor a 10yr life in those as well.

By the way, I reckon a diesel/electric drive would be the bees knees for many installs. An electric sail drive like and a small diesel driving a genny connected directly to the saildrive (or whisperdrive). You can then site the engine where you want it and not where a drive shaft determins it has to be.

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10 kilowatt motor $3000

48 volt x 200 amp hour lith ytt batteries $8000

48 to 12 volt converter say guessing $500

Charger $2000

Honda generator 2 kilowatt $3000

Some labour charges depending.

 

So way less than $20,000 without recurring costs for maintenance except a drive belt replacement every year or so.

The way I would be using the yacht, that is waiting for the wind, the batteries should last a lifetime with these types having a 0% reduction in capacity for 7000 cycles to less than 20% depth of discharge.

At 50% DOD these will have 5000 cycles with no loss of capacity.

Now with the generator aboard, if we needed to motor for a while it would be wise to use the genny rather than deeply discharging the batteries and in this fashion they should last well past the end of my lifetime.

By reducing the batteries to 100 amp hours at 48 volts probably do the above system for around 12 grand.

My house loads would likely be easily covered especially well with the 48 volt 200 amp setup, where say 100 amp draw per day at 12 volts becomes insignificant,

The 200 amp batteries would be about 8 cubic feet and weigh 94 kg.

Now my motor weighs roughly 200 kg the fuel 228 litres is almost 200 kg plus I have 140 kg of house and start batteries aboard. Thats 540 kg for the honour of vibrating, noisy beast within.

So with the 200 amp hour setup I could ditch around 400 kg! Plus lots more space.

This is only a rough estimate that is a simple indication only.

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