Wednesday, December 4, 2013

Re: [Electric Boats] RE: Harbor Test 2013

 

Eric
That's what she weighs in the travel lift.
Originally the designer had it speced to be 11,000 lbs but, hinterholler the builder refused to build it that light. Not sure where all the weight was added exactly but' she's got a big beam over 11 feet.

Mike

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From: <cirejay@hotmail.com>
Sender: electricboats@yahoogroups.com
Date: Wed, 04 Dec 2013 14:02:56 -0800
To: <electricboats@yahoogroups.com>
ReplyTo: electricboats@yahoogroups.com
Subject: [Electric Boats] RE: Harbor Test 2013

 

Capt. Mike, I can understand 300# for the mast on a Nonsuch 30 but how did it get up to 8 tons displacement? 

 

eric SV Meander

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[Electric Boats] RE: Harbor Test 2013

 

Capt. Mike, I can understand 300# for the mast on a Nonsuch 30 but how did it get up to 8 tons displacement? 

 

eric SV Meander

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[Electric Boats] Harbor Test 2013

 

Early this past season I did several harbor tests with my Thoosa 9000 EP system on my 8 ton 30 foot sailboat. The yard was delayed in stepping my boat's 300 lb mast so I did tests with it off and on the boat and made a graph comparing the two. I also made another graph of a test I did at the end of the season in 2011 with the boats bottom slightly fouled and compared with this seasons test with a clean hull.:


Capt. Mike
http://biankablog.blogspot.com

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[Electric Boats] RE: Pearson 10M electric power?

 

Copied directly from a TCCH-6000 battery charger configuration worksheet:

This is the Max Wattage Output from the Charger in Relation to the Inpute Sources
Input Output
120V 15A 1200
240V 30A 4000

 

For example, 120vac = 83vdc.  83vdc * 15a = about 1200 watts of usable DC power.

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Monday, December 2, 2013

Re: [Electric Boats] RE: Pearson 10M electric power?

 

I challenge  your voltage calc for 240vac. Remember that the 240 is rms. A little experment will show you the voltage potential. Take a 600 volt capacitor and a diode bridge and charge that capacitor of any size without load and measure the voltage.

Be careful a capacitor of any size at that voltage can be deadly. Although a bleed off resistor should bridge the terminals of the capacitor bleed off takes a while.

The point? If you feed the wrong circuit to high a voltage it will smoke, or more.

Be safe, stay happy.

Kevin

On Nov 30, 2013 6:53 PM, <dfwmcse@yahoo.com> wrote:
 

I have a slightly different take on the generator sizing.

 

Chances are, the bottleneck for this whole system is going to be the charger.  Shore power in the best circumstances: 240vac at 50 amps,  240vac is around 152vdc, and the charger is not going to actually pull all 50 amps or it risks tipping the circuit breaker.  45 amps is closer to the max current on a charger connected to shore power.  That's around 6800 watts, give or take.  A 7kw charger would be the ideal fit. I chose a 6kw charger because stepping up to an 8kw charger added another 30 percent to that component cost.

 

The same charger can use the (AC or DC) output from a gen set.  So, in my case, it made sense to just keep the existing 7kw Phasor gen set I already have.  Well, to be totally honest, I've pulled that gen set and set it on a bench in my shop.  I might not put any generator at all back on the boat.  I had a heck of a time finding a generator that was 1) well documented by the manufacturer and 2) available at a reasonable price.  If prices come down about 25 percent, and that documentation problem gets corrected, I'll revisit installing a new generator.

 

At 4 knots I should have a range of about 16 nm under battery power alone. That's a pretty good range for an auxiliary propulsion system that can be recharged just by sailing, and sailing is what I prefer to do anyway.

 

I guess the bottom line here is, when you are designing your PBBPS, you need to first identify how much power (in watts) is required to move your vessel at different speeds.  Work from there.  You may find out that 15hp is more than you need for a 33 foot vessel. One thing I do recommend considering, very strongly, is the nominal voltage of your battery pack.  It is very easy to find converters, inverters, and chargers for 48v packs.  Above that, however, and the options suddenly narrow quite a bit.



---In electricboats@yahoogroups.com, <gvanderhart@...> wrote:

Preston,

 

I do not have an electric propulsion system, so you may want to take my advice with a grain of salt.  However, I am an electrical engineer, so I know something about creating electrical systems that work.  Perhaps my comments will nudge other responses.

 

Since you want to power a fairly large sailboat and since you are removing an inboard motor, I would recommend a 10-20hp electric motor.  To get that kind of power requires at least 48 volts, or one bank of four 12V batteries.  The principle for voltage selection is: the higher the voltage, the lower the current.  Large currents can require more copper than is practical.  The best connection to the propeller is an AC motor with a motor controller.  The input to the motor controller is DC, but you get the advantage of a reliable brushless motor and more importantly, speed control.

 

There are a lot of tradeoffs with regard to how many banks you need (adds Ah) and how fast you can recharge those banks.  At least you will need a charger that connects to shore power.  If you already have a device that changes AC to charging DC, an AC gen set is probably the best way to avoid duplication of equipment.  If you choose the charger carefully (make sure the manual says you can connect other electrical equipment while it is charging), then you can use the power from the gen set/charger to run the motor.  In this case, the batteries keep the charger from shutting down (which it would do if it did not detect a minimum voltage), but the current from the charger is used to power the motor.  It makes sense to me to approximately match the charger output (volts * amps = watts) with the cruising volts * amps needed by the motor.

 

Gary



---In electricboats@yahoogroups.com, <electricboats@yahoogroups.com> wrote:

So, I'd love to "electrify" my old faithful Pearson 10M (33 ft.) sloop.  
The Atomic 4 that has served for so many years is shot.
I'd like to put in an electric motor (what kind, voltage, etc?), a water cooled generator or motor to run an alternator, a battery bank (of what kind of batteries?) and a controller of some sort.

I'll pull the old engine, get rid of the gas tank, and start over.

Multiples of 6 volts?  A 48 volt sweeper or golf cart motor?  A bank of 6 volt batteries, what type?  Generator, or motor w/alternator?  

I'm figuring 4,000 watts for the generation system, max 800-1200 rpms at the shaft…
15hp would drive the boat nicely...
(In my fantasy, a Hydrogen fuel cell system, fed by cng or something, would be cool…)
But, when I wake up and look at my checking account… probably a diesel gen set is the answer…

Thoughts, recommendations, guidance?
Best,

Preston

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Sunday, December 1, 2013

Re: [Electric Boats] RE: Pearson 10M electric power?

 



12 kW is correct for peak electrical measurement, but not when considered as heat energy.
 
240 VAC is a peak measurement. It occurs 60 times a second. But ability to handle heat is what determines how expensive it is to manufacture a charger, and for that he is correct to use some sort of average kW value rather than peak. I didn't check his numbers; they're based on whatever his assumptions are. But his is the right direction to go when considering heat load.
 
What we don't know is whether the manufacturer of the charger has already taken that into account or not....and that's critical.
Roger L.
....
..........
 
 
----- Original Message -----
From: han
Sent: Sunday, December 01, 2013 5:09 AM
Subject: Re: [Electric Boats] RE: Pearson 10M electric power?

240 V x 50 Amps = 12 kW.
No ?


On 30/11/2013 22:04, dfwmcse@yahoo.com wrote:
> Chances are, the bottleneck for this whole system is going to be the
> charger.  Shore power in the best circumstances: 240vac at 50 amps, 
> 240vac is around 152vdc, and the charger is not going to actually pull
> all 50 amps or it risks tipping the circuit breaker.  45 amps is
> closer to the max current on a charger connected to shore power. 
> That's around 6800 watts, give or take.  A 7kw charger would be the
> ideal fit. I chose a 6kw charger because stepping up to an 8kw charger
> added another 30 percent to that component cost.



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Re: [Electric Boats] RE: Pearson 10M electric power?

 

240 V x 50 Amps = 12 kW.
No ?

On 30/11/2013 22:04, dfwmcse@yahoo.com wrote:
> Chances are, the bottleneck for this whole system is going to be the
> charger. Shore power in the best circumstances: 240vac at 50 amps,
> 240vac is around 152vdc, and the charger is not going to actually pull
> all 50 amps or it risks tipping the circuit breaker. 45 amps is
> closer to the max current on a charger connected to shore power.
> That's around 6800 watts, give or take. A 7kw charger would be the
> ideal fit. I chose a 6kw charger because stepping up to an 8kw charger
> added another 30 percent to that component cost.

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