Cruisers Forum
 


Join CruisersForum Today

Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on Cruisers Forums. Advertise Here
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 29-01-2018, 10:23   #1
Registered User

Join Date: Jan 2018
Posts: 1
Ensuring Stable 12v DC

I am remolding my boat and will start on my electrical system soon. I am leaning towards a 12 DC boat. Meaning terminate my shore power / AC Generator / Solar / Wind ..etc at the batter charger. My 120 V AC would run through a DC / AC Converter. The question is whether I should use a buck converter or DC / DC converter that would stabilize my 12v DC output. I am just wondering if it's worth the investment?

Cheers,
__________________

sv.BlueLagoon is offline   Reply With Quote
Old 29-01-2018, 10:41   #2
Registered User
 
ccannan's Avatar

Join Date: Jun 2003
Boat: Alubat, OVNI 47
Posts: 264
Images: 5
Re: Ensuring Stable 12v DC

It depends on your 12vdc equipment sensitivity. Most 12vdc equipment will happily accept from 14v to 11v. Each device has its electrical requirements listed on it, and in its' manual.

BTW, a common name for a DC to AC converter is inverter.
__________________

__________________
Chip
ccannan is offline   Reply With Quote
Old 29-01-2018, 10:53   #3
Registered User
 
Privilege's Avatar

Join Date: Oct 2009
Location: Bermuda
Boat: Privilege 435
Posts: 554
Images: 12
Re: Ensuring Stable 12v DC

..and you will need different chargers; one for your A/C, one for your solar and one for your wind.
Privilege is offline   Reply With Quote
Old 29-01-2018, 11:10   #4
Registered User
 
travellerw's Avatar

Join Date: Jan 2014
Location: Grenada
Boat: Fortuna Island Spirit 40
Posts: 2,291
Re: Ensuring Stable 12v DC

Quote:
Originally Posted by sv.BlueLagoon View Post
I am remolding my boat and will start on my electrical system soon. I am leaning towards a 12 DC boat. Meaning terminate my shore power / AC Generator / Solar / Wind ..etc at the batter charger. My 120 V AC would run through a DC / AC Converter. The question is whether I should use a buck converter or DC / DC converter that would stabilize my 12v DC output. I am just wondering if it's worth the investment?

Cheers,
Personally I think a DC/DC converter is a waste of money and power. Pretty much all devices on our boat are tolerant from 11-16V. A DC/DC converter doesn't really offer any benefits. I guess the only real benefit I could see is surge supression.

I wouldn't bother with it. Instead put the money into quality connectors, wires and terminal blocks. Thats a much better investment.
travellerw is offline   Reply With Quote
Old 29-01-2018, 11:51   #5
Registered User
 
Viking Sailor's Avatar

Join Date: Nov 2006
Location: San Francisco Bay
Boat: Fantasia 35
Posts: 1,191
Re: Ensuring Stable 12v DC

One exception is the Ham radio transceiver. These units are much happier when powered by 13.8 volts from a car alternator/battery system.
Viking Sailor is online now   Reply With Quote
Old 29-01-2018, 12:24   #6
Registered User
 
Colin A's Avatar

Join Date: Mar 2013
Location: East of the river CT
Boat: Oday Mariner 19 , Four Winns Marquis 16 OB, Kingfisher III
Posts: 644
Send a message via Skype™ to Colin A
Re: Ensuring Stable 12v DC

Quote:
Originally Posted by Viking Sailor View Post
One exception is the Ham radio transceiver. These units are much happier when powered by 13.8 volts from a car alternator/battery system.
Yep Radio equipment tends to prefer a more stable power source. Certain electronics as well. But for 90% of boat stuff kind of a non issue.
__________________
mysite: Colinism.com
Colin A is offline   Reply With Quote
Old 29-01-2018, 12:57   #7
Registered User

Join Date: Mar 2014
Location: Oz
Posts: 894
Re: Ensuring Stable 12v DC

If you have big electric winches, the power draw can be high enough to temporarily drop voltage down to instruments below their cutoff and so they switch off and then reboot. Particularly disconcerting when using your radar in fog or driving rain, all of a sudden you can't see anything for a couple of minutes. This can happen if batteries have been run down when sailing all night. We installed a Victron DC ~DC stabilizer (Orion isolated 18 amp - $116) that powers all the electronics and radar and have not had a problem since.
Bean Counter is offline   Reply With Quote
Old 29-01-2018, 13:00   #8
Registered User
 
travellerw's Avatar

Join Date: Jan 2014
Location: Grenada
Boat: Fortuna Island Spirit 40
Posts: 2,291
Re: Ensuring Stable 12v DC

Now I don't know anything about HAM radios, but I really doubt the new generations would work any better on higher voltage. Modern radios would be designed with a stable power supply built in and should operate exactly the same on any voltage listed in thier range. That would also hold true for any electronics. As long as you aren't running electronics from the 80s, they will operate exactly the same on 11 - 16V.

The only modern device on a sailboat that may benefit would be the windlass or an electric winch. They do operate better when the voltage is higher, BUT, you would need a hell of a DC/DC converter to run them (with probably %10 loss to heat).
travellerw is offline   Reply With Quote
Old 29-01-2018, 13:03   #9
֍֎֍֎֍֎֍֎֍֎

Cruisers Forum Supporter

Join Date: Apr 2006
Posts: 15,129
Re: Ensuring Stable 12v DC

Most "12" volt gear is designed for a specific range, often "13.8 volts plus or minus ten percent" and often it is expected to run from 14.4 volts (the maximum output from an automotive alternator) down to around 11.5 volts, that being a dead 12 volt battery.

Aside from radio transmitters sometimes getting unstable at 11.5 volts or less, and cheap LED lights or filament bulbs varying in brightness with voltage changes, I can't think of what on your boat would care about "stabilized" DC. There are a lot of FUD "stabilizers" sold to the car audio crowd but they are mainly pointless. Especially if you take care of your batteries and voltage drops in the wiring.
hellosailor is offline   Reply With Quote
Old 29-01-2018, 14:21   #10
Registered User

Join Date: Jun 2013
Location: canada
Posts: 2,598
Re: Ensuring Stable 12v DC

that is what a battery is for.... it goes between the AC charger and the DC loads...
smac999 is offline   Reply With Quote
Old 29-01-2018, 14:35   #11
Registered User
 
S/V Illusion's Avatar

Join Date: Oct 2007
Location: Lakewood Ranch, FLORIDA
Boat: Alden 50, Sarasota, Florida
Posts: 2,166
Re: Ensuring Stable 12v DC

Quote:
Originally Posted by travellerw View Post
Now I don't know anything about HAM radios, but I really doubt the new generations would work any better on higher voltage. Modern radios would be designed with a stable power supply built in and should operate exactly the same on any voltage listed in thier range. That would also hold true for any electronics. As long as you aren't running electronics from the 80s, they will operate exactly the same on 11 - 16V.

The only modern device on a sailboat that may benefit would be the windlass or an electric winch. They do operate better when the voltage is higher, BUT, you would need a hell of a DC/DC converter to run them (with probably %10 loss to heat).
Actually, most radios ( ham or marine) have no power supply but rather depend on external power. If unregulated, they behave poorly below 13 volts. The same is true of other electronics, most commonly autopilots which are unreliable with lower voltage.

A reasonable (read - cheap) alternative to whole boat converters is single unit voltage stabilizers which have the added advantage of supplying a selectable output voltage regardless of supply voltage such that a 12 v source can be raised to 13+ where necessary.
S/V Illusion is offline   Reply With Quote
Old 29-01-2018, 15:32   #12
Registered User
 
travellerw's Avatar

Join Date: Jan 2014
Location: Grenada
Boat: Fortuna Island Spirit 40
Posts: 2,291
Re: Ensuring Stable 12v DC

Quote:
Originally Posted by S/V Illusion View Post
Actually, most radios ( ham or marine) have no power supply but rather depend on external power. If unregulated, they behave poorly below 13 volts. The same is true of other electronics, most commonly autopilots which are unreliable with lower voltage.

A reasonable (read - cheap) alternative to whole boat converters is single unit voltage stabilizers which have the added advantage of supplying a selectable output voltage regardless of supply voltage such that a 12 v source can be raised to 13+ where necessary.
Hmmm.. News to me.. Both my VHF (pretty sure that is considered marine) and autopilot that died during our lightening strike had built-in power circuits. Since I have an EE background I took both apart to discover the damage and see if they could be repaired. I will agree to disagree with you..

However... Yes autopilots can perform poorly below 12.4V since they usually have a large electric motor used for moving the rudder (either as an actuator, or a pump for the hydraulics). The electronics, however do not care if the voltage is 12V or 15V.
travellerw is offline   Reply With Quote
Old 29-01-2018, 16:14   #13
֍֎֍֎֍֎֍֎֍֎

Cruisers Forum Supporter

Join Date: Apr 2006
Posts: 15,129
Re: Ensuring Stable 12v DC

" If unregulated, they behave poorly below 13 volts."
And you are basing that on what?

The radios I have worked with, documented by their manuals, usually say 13.8 volts plus or minus either 10% or a more generous 15%.

So for the one it is 12.42 volts minimum, for the other 11.73 volts. And if the ship' s battery is down to 11.73 volts, that's effectively a dead battery anyway. Some, like the old Drake radios, were actually quite happy at twelve and below. Others, including some popular Icom's, are notorious for misbehaving at "twelve". (Which is still a 60% discharged 12-volt battery.)

It is one thing to run a voltage booster when and if the battery bank is down, quite another to need it all the time.
hellosailor is offline   Reply With Quote
Old 29-01-2018, 17:31   #14
Registered User
 
travellerw's Avatar

Join Date: Jan 2014
Location: Grenada
Boat: Fortuna Island Spirit 40
Posts: 2,291
Re: Ensuring Stable 12v DC

Quote:
Originally Posted by hellosailor View Post
" If unregulated, they behave poorly below 13 volts."
And you are basing that on what?

The radios I have worked with, documented by their manuals, usually say 13.8 volts plus or minus either 10% or a more generous 15%.

So for the one it is 12.42 volts minimum, for the other 11.73 volts. And if the ship' s battery is down to 11.73 volts, that's effectively a dead battery anyway. Some, like the old Drake radios, were actually quite happy at twelve and below. Others, including some popular Icom's, are notorious for misbehaving at "twelve". (Which is still a 60% discharged 12-volt battery.)

It is one thing to run a voltage booster when and if the battery bank is down, quite another to need it all the time.
Sometimes I really wished CF had a "LIKE" button!
travellerw is offline   Reply With Quote
Old 29-01-2018, 22:37   #15
Registered User

Join Date: Jan 2017
Posts: 11,769
Re: Ensuring Stable 12v DC

Deal with the root cause, not bandaging symptoms.

If big loads are pulling your voltage that low, you should probably get your genny fired up beforehand.

Or get a bigger bank, or go to LFP.
__________________

john61ct is online now   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Need 12V stable power supply for WIFI router SFH Marine Electronics 20 09-06-2015 17:50
Shelf-Stable Cheese RainDog Provisioning: Food & Drink 4 21-01-2011 12:53
New Owner's Cat Capsizes: Stable, Though Upside Down; All Crew Survive CastOff Multihull Sailboats 39 16-09-2010 12:21
Safe, stable, family cruiser... settlednomad Monohull Sailboats 17 23-04-2009 07:12
Ideas on a Forgiving, Stable Tender / Dinghy ? ssullivan Auxiliary Equipment & Dinghy 3 06-06-2007 15:51



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 13:00.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.