Reply
 
Thread Tools Display Modes
 
Old 06-01-2014, 03:37 PM   #41
Wil
Veteran Member
 
City: Pacific NW
Country: US
Join Date: Jul 2013
Posts: 72
Quote:
Originally Posted by Ski in NC View Post
Watch or read "Mosquito Coast"!!!!
Thanks for the tip, will do!!!
__________________
Advertisement

Wil is offline   Reply With Quote
Old 06-01-2014, 03:39 PM   #42
Wil
Veteran Member
 
City: Pacific NW
Country: US
Join Date: Jul 2013
Posts: 72
Quote:
Originally Posted by psneeld View Post
yes..yes...I think most here understand basic electricity...
Basic question: do you think 6vdc is as 'good' at performing work efficiently as 12vdc?
__________________

Wil is offline   Reply With Quote
Old 06-01-2014, 05:03 PM   #43
Guru
 
psneeld's Avatar
 
City: Avalon, NJ
Country: USA
Vessel Name: Freedom
Vessel Model: Albin 40
Join Date: Oct 2011
Posts: 15,913
Quote:
Originally Posted by Wil View Post
Basic question: do you think 6vdc is as 'good' at performing work efficiently as 12vdc?
Just the question alone speaks you are missing most of our points.

Sure higher voltage, smaller gear and smaller losses...

Go for it...

but first...re-read this about a million times...caltexflanc posted it in post #33

I see so many newbies spending a lot of time and money getting the boat to match what they think it should have based on reading and dreaming and other people's opinions (which are based, at best, on how they happen to use their boat, and/or their budget.).


probably after rereading it only 500,000 times...you may see what many of us. and if not certainly 2 of us, are saying....
psneeld is offline   Reply With Quote
Old 06-01-2014, 05:52 PM   #44
Wil
Veteran Member
 
City: Pacific NW
Country: US
Join Date: Jul 2013
Posts: 72
Quote:
Originally Posted by psneeld View Post
Just the question alone speaks you are missing most of our points.

Sure higher voltage, smaller gear and smaller losses...

Go for it...

but first...re-read this about a million times...caltexflanc posted it in post #33

I see so many newbies spending a lot of time and money getting the boat to match what they think it should have based on reading and dreaming and other people's opinions (which are based, at best, on how they happen to use their boat, and/or their budget.).


probably after rereading it only 500,000 times...you may see what many of us. and if not certainly 2 of us, are saying....
Absolutely couldn't agree more with caltexflanc, you, and all others about newbies (and maybe some oldies even) getting caught up in their own dreams and other people's opinions/positions, thus wasting alot of money. What I don't seem to be able to get across is that This Is A Thought Exercise. Sure, I advocate for 24v heartily--but am I actually going to do anything about it? That is why I started this really good give-and-take conversation in the first place.

I want to know the actual reasons behind the 'norm' and 'convention', especially when there seems to be a better alternative that a lot of other boats are already using. I knew from the beginning that it would be an expensive pita, but I want to know just exactly why. What I've come up with so far is that the availability of a lot of the 12v items will be very spotty in 24v, so that goes a long way towards ruling out pure 24v (but what do the bigger boats do?). That having a 12/24v system would be unnecessarily complex. Good reasons those, and that might be why I don't do it. Hope that clarifies things.
Wil is offline   Reply With Quote
Old 06-01-2014, 05:56 PM   #45
Guru
 
psneeld's Avatar
 
City: Avalon, NJ
Country: USA
Vessel Name: Freedom
Vessel Model: Albin 40
Join Date: Oct 2011
Posts: 15,913
Quote:
Originally Posted by Wil View Post
Absolutely couldn't agree more with caltexflanc, you, and all others about newbies (and maybe some oldies even) getting caught up in their own dreams and other people's opinions/positions, thus wasting alot of money. What I don't seem to be able to get across is that This Is A Thought Exercise. Sure, I advocate for 24v heartily--but am I actually going to do anything about it? That is why I started this really good give-and-take conversation in the first place.

I want to know the actual reasons behind the 'norm' and 'convention', especially when there seems to be a better alternative that a lot of other boats are already using. I knew from the beginning that it would be an expensive pita, but I want to know just exactly why. What I've come up with so far is that the availability of a lot of the 12v items will be very spotty in 24v, so that goes a long way towards ruling out pure 24v (but what do the bigger boats do?). That having a 12/24v system would be unnecessarily complex. Good reasons those, and that might be why I don't do it. Hope that clarifies things.
Maybe because the "better" is so slight...no one else cares....

but maybe if you keep looking...someone might be able to point to real world numbers why a total 24V system would be better...but I've never seen any (other than for a specific piece of equipment like a thruster)...till then talking theory and reality is a fun mental exercise...so how many so far have thought a changeover was good?
psneeld is offline   Reply With Quote
Old 06-01-2014, 06:10 PM   #46
Guru
 
caltexflanc's Avatar
 
City: North Carolina for now
Country: USA
Vessel Name: Small Incentive
Vessel Model: Boston Whaler 130 Sport
Join Date: Aug 2011
Posts: 3,801
Maybe I live in an alternative reality, but I simply just do not get this "scarcity of 24 volt" stuff. It is all very available on my planet. As I said before, I have had no problem getting 32 volt stuff either. What am I missing here? 24-12 converters (or 32 - 12 for that matter) are easy to source if you need them.
__________________
George

"There's the Right Way, the Wrong Way, and what some guy says he's gotten away with"
caltexflanc is online now   Reply With Quote
Old 06-01-2014, 06:11 PM   #47
Wil
Veteran Member
 
City: Pacific NW
Country: US
Join Date: Jul 2013
Posts: 72
psneeld said:
...so how many so far have thought a changeover was good?
__________________________________________________ _______________________

..... and how many are on 'pure' 24v or higher (just the DC side) boats? Is there such a thing? Are they all 12/24v+ combos with a very substantial amount (half or more?) of the electrical items being 12v?
Wil is offline   Reply With Quote
Old 06-01-2014, 06:17 PM   #48
Guru
 
psneeld's Avatar
 
City: Avalon, NJ
Country: USA
Vessel Name: Freedom
Vessel Model: Albin 40
Join Date: Oct 2011
Posts: 15,913
Quote:
Originally Posted by caltexflanc View Post
Maybe I live in an alternative reality, but I simply just do not get this "scarcity of 24 volt" stuff. It is all very available on my planet. As I said before, I have had no problem getting 32 volt stuff either. What am I missing here? 24-12 converters (or 32 - 12 for that matter) are easy to source if you need them.
it's all available and not THAT hard to get...but like twinkies over organic lettuce...

every 7-11 and Little General has twinkies...not organic lettuce...

pull into any decent port and 24V stuff and service is certainly available...

I agree having 2 different voltage systems on a boat is no big deal...but not only 24V or switching to it if you only want to add a 24V appliance or 2....
psneeld is offline   Reply With Quote
Old 06-01-2014, 07:38 PM   #49
Wil
Veteran Member
 
City: Pacific NW
Country: US
Join Date: Jul 2013
Posts: 72
Quote:
Originally Posted by FF View Post
The only item that is a power hog on most boats is the refrigeration system.
A boat with a propane reefer and freezer, and range only requires minor electric for anchored out weeks or months. WE DO IT!
What make/model of fridge and freezer do you have?
Wil is offline   Reply With Quote
Old 06-01-2014, 10:43 PM   #50
Veteran Member
 
Cathy and David's Avatar
 
City: Hilton Head, SC
Country: USA
Vessel Name: Irie Daze
Vessel Model: Albin 43 Sundeck
Join Date: Mar 2014
Posts: 62
???

I read this and get befuddled. Some comments seem to suggest that going to a higher voltage either in DC or AC reduces work. Wattage is the electrical definition of work and the load dictates wattage thus the work. Granted electrical current reduces with higher voltage given the same wattage. However the work remains the same. 24 volts and 12 volts will run the same temp if the wiring is sized accordingly. One is not more efficient than the other given proper wire sizing. Work is work and nothing is free and you can not create nor destroy energy. Physics are Physics!
Cathy and David is offline   Reply With Quote
Old 06-01-2014, 11:43 PM   #51
Wil
Veteran Member
 
City: Pacific NW
Country: US
Join Date: Jul 2013
Posts: 72
Quote:
Originally Posted by Cathy and David View Post
Work is work and nothing is free and you can not create nor destroy energy. Physics are Physics!
Agreed. Why do bigger boats go to higher DC voltages?
Wil is offline   Reply With Quote
Old 06-01-2014, 11:58 PM   #52
Guru
 
Ski in NC's Avatar
 
City: Wilmington, NC
Country: USA
Vessel Name: Louisa
Vessel Model: Custom Built 38
Join Date: Jan 2014
Posts: 3,888
Quote:
Originally Posted by Wil View Post
Agreed. Why do bigger boats go to higher DC voltages?
Because of the starters!!! Covered that already.
Ski in NC is offline   Reply With Quote
Old 06-02-2014, 12:04 AM   #53
Wil
Veteran Member
 
City: Pacific NW
Country: US
Join Date: Jul 2013
Posts: 72
Quote:
Originally Posted by Ski in NC View Post
Because of the starters!!! Covered that already.
That is just too simplistic thinking. I said that larger flywheel diameters would solve your issue about a 'large 12v starter diameter'. There are other reasons why large boats go to 24v and higher.
Wil is offline   Reply With Quote
Old 06-02-2014, 04:01 AM   #54
TF Site Team
 
Peter B's Avatar
 
City: Brisbane
Country: Australia
Vessel Name: Lotus
Vessel Model: Clipper (CHB) 34 Sedan/Europa style
Join Date: Jun 2008
Posts: 6,669
Send a message via Skype™ to Peter B
Quote:
Originally Posted by Wil View Post
That is just too simplistic thinking. I said that larger flywheel diameters would solve your issue about a 'large 12v starter diameter'. There are other reasons why large boats go to 24v and higher.
Maybe the answer is as simple as them wanting to save weight and cost of heavier gauge wiring, Wil, of which there is plenty on the large vessels. It seems to go up exponentially, the larger the boat, more of everything along with the volume and displacement. Maybe too simple, but it is a serious suggestion. Otherwise there appears to be so little in it re efficiency as to not make it worth it to change. There are davit and winch systems out there with plenty of power, so grunt appears not to be an issue. You just need the heavy duty wiring to those items. Maybe 24v is better than 12v, but the reason why we stick with what we have now is probably, in the end, as mundane as the same reason the US does not plan to go 240vAC. That is too much already out there including plant and stock existing in the present format. So too expensive to make the change. So you sort of answered your own question, right there.

As to why 24v has not bumped 12v like 12v did to 6v, well, same reason as above, and the only car I remember with a 6v system was early VW beetles, and they had huge issues getting bright enough lights, so gave in to 12v in the end mainly for that reason I think. Maybe if they had had LEDs back then..?
__________________
Pete
Peter B is offline   Reply With Quote
Old 06-02-2014, 06:28 AM   #55
FF
Guru
 
FF's Avatar
 
Join Date: Oct 2007
Posts: 16,530
I see so many newbies spending a lot of time and money getting the boat to match what they think it should have based on reading and dreaming and other people's opinions (which are based, at best, on how they happen to use their boat, and/or their budget.).

At one boatyard I watched in horror as two novices destroyed a steel Abaking Rasmussen cutter about 50 ft that had done 2 circumnavigations (Dolfijn) with only a couple as crew.

Their idea of cruising came from Cruising World , a mag that then did not even have a tech editor!!

Bigger boats choose 24V as loads are bigger and the wiring and gear is cheaper than what the next size up boat does , all AC .
FF is offline   Reply With Quote
Old 06-02-2014, 06:33 AM   #56
Guru
 
psneeld's Avatar
 
City: Avalon, NJ
Country: USA
Vessel Name: Freedom
Vessel Model: Albin 40
Join Date: Oct 2011
Posts: 15,913
Often the simple answers are the correct ones.

Dreams aren't born in facts usually......but reality is.
psneeld is offline   Reply With Quote
Old 06-02-2014, 08:20 AM   #57
Dauntless Award
 
Wxx3's Avatar
 
City: New York, NY
Country: USA
Vessel Name: Dauntless
Vessel Model: Kadey Krogen 42 - 148
Join Date: Jan 2013
Posts: 2,313
Quote:
Originally Posted by Wil View Post
Ok, let me try to do that with specific examples. Inverters with 24v vs. 12v inputs run cooler & more efficiently, refrigeration compressors with 24v vs. 12v inputs run cooler and more efficiently, 24v anchor winches are more powerful than 12v winches with smaller wire runs. Using less current and more voltage is intrinsically more efficient and powerful. By its own definition, 24v is a more efficient and cooler-running system than 12v. Of course there's a limitation on how high one can go in DC voltage, but that isn't something I've researched. By the same logic, do you think a 6v system would be just as good as a 12v system? If not, that is exactly the same reason why I think 24v is better than 12v.
ASSUMING all of your assumptions are correct in the above statement the issue you are ignoring is the tremendous infrastructure out there to support 12v things (thank you cars).

So yes, while 24v systems may be inherently more efficient, because of economies of scale, 12v things will cost less than half the price for any given thing.

So, while you save 2-3% in electricity use and transmission, you are losing at least 50% in item costs.

People spending a few million $$ for a 65' boat, probably don't car that a replacement alternator costs a few thousand.

I do.

As an aside, the best change I made on my boat was switcihing my 120v fridge and freezer for 12v and adding four 110w solar panels to my pilot house roof. Yes, within the week, I will post the details)
__________________
M/Y Dauntless, New York
a Kadey Krogen 42 Currently https://share.delorme.com/dauntless
Blog: https://dauntlessatsea.com
Find us: https://share.delorme.com/dauntless
Wxx3 is offline   Reply With Quote
Old 06-02-2014, 11:14 AM   #58
Guru
 
Ski in NC's Avatar
 
City: Wilmington, NC
Country: USA
Vessel Name: Louisa
Vessel Model: Custom Built 38
Join Date: Jan 2014
Posts: 3,888
Quote:
Originally Posted by Wil View Post
That is just too simplistic thinking. I said that larger flywheel diameters would solve your issue about a 'large 12v starter diameter'. There are other reasons why large boats go to 24v and higher.
Might be simplistic, but pretty accurate.

Flywheels are built to SAE standards, so things being driven can be standardized. If you build a bigger fw to accomodate the wider engine block and wider starter, you just boxed your engine company out of many driven components (like marine gears, generators, pumps, automotive transmissions), or forced the need for machined adapters.

It is cheaper to bolt on a 24v starter than to redesign to a larger fw size.

Regarding US power engineering and 120v vs 220v elsewhere: US power engineers are not idiots. Yes we use 120v for small household loads. But we also use 240v for larger power loads. And go into any industrial plant and you see three phase, which is significantly more efficient than any of the above. Get into decent sized motors and volts go up: 240v3ph for little stuff. 10hp up or so- 480v, 300hp up or so- 4kV. Base load generators- around 30kV into the switchyard, around 250 to 500kV out of the yard. Well understood and practiced the concept of selecting voltages to minimize resistance losses.

But as in boats, you have to apply costs to the analysis. There is little benefit in designing a 480v3ph toaster. Duty cycle, line losses and cost of mfg would make that a stupid decision.

Calculate the cost of all the line losses in your proposed boat for its entire life cycle using 12v. Repeat using 24v. Write the numbers down. Now estimate the cost of specifying and maintaining a 24v system vs 12v. Write that number down. Compare numbers. That is why small boats stick with 12v. Like the toaster example.
Ski in NC is offline   Reply With Quote
Old 06-02-2014, 02:05 PM   #59
Wil
Veteran Member
 
City: Pacific NW
Country: US
Join Date: Jul 2013
Posts: 72
Quote:
Originally Posted by Ski in NC View Post
Might be simplistic, but pretty accurate.

Flywheels are built to SAE standards, so things being driven can be standardized. If you build a bigger fw to accomodate the wider engine block and wider starter, you just boxed your engine company out of many driven components (like marine gears, generators, pumps, automotive transmissions), or forced the need for machined adapters.

It is cheaper to bolt on a 24v starter than to redesign to a larger fw size.

Regarding US power engineering and 120v vs 220v elsewhere: US power engineers are not idiots. Yes we use 120v for small household loads. But we also use 240v for larger power loads. And go into any industrial plant and you see three phase, which is significantly more efficient than any of the above. Get into decent sized motors and volts go up: 240v3ph for little stuff. 10hp up or so- 480v, 300hp up or so- 4kV. Base load generators- around 30kV into the switchyard, around 250 to 500kV out of the yard. Well understood and practiced the concept of selecting voltages to minimize resistance losses.

But as in boats, you have to apply costs to the analysis. There is little benefit in designing a 480v3ph toaster. Duty cycle, line losses and cost of mfg would make that a stupid decision.

Calculate the cost of all the line losses in your proposed boat for its entire life cycle using 12v. Repeat using 24v. Write the numbers down. Now estimate the cost of specifying and maintaining a 24v system vs 12v. Write that number down. Compare numbers. That is why small boats stick with 12v. Like the toaster example.
Great answer with excellent detail and reasoning. Thank you. I got it, understand what you propose, and agree that's what I should do. I don't have the skills--yet--to do the analysis you speak of, that's what I was hoping someone on TF might have already done. It's along the lines of why I asked if anyone had already done a 24v conversion and what was the result.
Wil is offline   Reply With Quote
Old 06-02-2014, 02:10 PM   #60
Dauntless Award
 
Wxx3's Avatar
 
City: New York, NY
Country: USA
Vessel Name: Dauntless
Vessel Model: Kadey Krogen 42 - 148
Join Date: Jan 2013
Posts: 2,313
Quote:
Originally Posted by Wil View Post
Great answer with excellent detail and reasoning. Thank you. I got it, understand what you propose, and agree that's what I should do. I don't have the skills--yet--to do the analysis you speak of, that's what I was hoping someone on TF might have already done. It's along the lines of why I asked if anyone had already done a 24v conversion and what was the result.
Oh, I thought we were explaining why that person doesn't exist, so don't hold your breath waiting.
__________________

__________________
M/Y Dauntless, New York
a Kadey Krogen 42 Currently https://share.delorme.com/dauntless
Blog: https://dauntlessatsea.com
Find us: https://share.delorme.com/dauntless
Wxx3 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





All times are GMT -5. The time now is 08:39 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012