 |
06-04-2014, 07:41
|
#1
|
Registered User
Join Date: Sep 2012
Location: Halifax NS
Boat: C&C Frigate 36
Posts: 34
|
LED Polarity
I have installed LED steaming light but it doesn't work. We checked before I stepped the mast. I understand that polarity is important to LEDs. If I merely reverse the wires on the deck, would it solve the problem - if polarity is the problem. What would be the risks?
Electricity, especially direct, is most baffling to me.
Phil
|
|
|
06-04-2014, 07:45
|
#2
|
Registered User
Join Date: Oct 2011
Boat: Valiant 42
Posts: 6,008
|
Re: LED polarity
Phil,
Check with the light supplier. Many lights will not be damaged by reversal but some may be. If the light supplier used polarity protection then it will be ok to switch the polarity.
|
|
|
06-04-2014, 11:31
|
#3
|
Registered User
Join Date: Jan 2014
Location: St Michaels MD
Boat: F&C 44
Posts: 182
|
Re: LED polarity
Reverse the polarity. Polarity protection is easy and cheap so I can't imagine an LED running light designed without it. If it still doesn't work most likely a pulled or pinched wire when the mast was stepped. You did check that there is power where the wires connect?
|
|
|
08-04-2014, 19:12
|
#4
|
Registered User
Join Date: May 2011
Location: Lake Ont
Posts: 8,582
|
Re: LED polarity
Quote:
Originally Posted by SteveSails
Reverse the polarity. Polarity protection is easy and cheap so I can't imagine an LED running light designed without it. If it still doesn't work most likely a pulled or pinched wire when the mast was stepped. You did check that there is power where the wires connect?
|
The sort of LED (or LED fixture with integral regulation) that's meant for marine applications should be able to survive reversed 12v.
|
|
|
08-04-2014, 19:20
|
#5
|
Registered User
Join Date: Apr 2012
Posts: 585
|
Re: LED polarity
Light-emitting diode (LED)...diode means current will flow in only one direction through the device.
If the light is not ON the possible causes are:
- the LED is defective
- the LED is not getting the proper voltage (open wire or high resistance connection or voltage too low)
- the voltage polarity is reverse of that needed to flow through the diode(s)
If the polarity is reversed the diode will not be damaged (unless the voltage applied is high enough to cause a breakdown of the diode...much higher than your 12V supply).
|
|
|
09-04-2014, 04:11
|
#6
|
Nearly an old salt
Join Date: Jun 2009
Location: Lefkas Marina ,Greece
Boat: Bavaria 36
Posts: 22,801
|
Re: LED polarity
Most leds have an absolute max reverse breakdown voltage of about 5v by the way
Dave
__________________
Interested in smart boat technology, networking and all things tech
|
|
|
09-04-2014, 04:29
|
#7
|
Moderator Emeritus

Join Date: Nov 2008
Location: Lived aboard & cruised for 45 years,- now on a chair in my walk-in closet.
Boat: Morgan OI 413 1973 - Aythya
Posts: 8,504
|
Re: LED polarity
Quote:
Originally Posted by fryewe
Light-emitting diode (LED)...diode means current will flow in only one direction through the device. .....
|
'best statement yet on this thread here by fryewe.
You did not mention the type of socket on the bulb. If it's a double bayonet; then just reverse to bulb or the wires. I'd just turn the bulb 180 degrees.
__________________
Take care and joy, Aythya crew
|
|
|
09-04-2014, 05:00
|
#8
|
Moderator Emeritus

Join Date: May 2008
Location: Fort Lauderdale, FL
Boat: 48 Wauquiez Pilot Saloon
Posts: 5,972
|
Re: LED polarity
Quote:
Originally Posted by CaptForce
'best statement yet on this thread here by fryewe.
You did not mention the type of socket on the bulb. If it's a double bayonet; then just reverse to bulb or the wires. I'd just turn the bulb 180 degrees.
|
Capn' F's method has flaws rooted in laziness and efficiency...
There is nothing wrong with cutting two connectors, re-stripping, connecting, and sealing...
Your choice... You can do it the easy way... Or do it like the rest of us...
__________________
In the harsh marine environment, something is always in need of repair...
Mai Tai's fix everything...
|
|
|
09-04-2014, 08:27
|
#9
|
Registered User
Join Date: Oct 2011
Boat: Valiant 42
Posts: 6,008
|
Re: LED Polarity
Lots of misinformation here. Many double bayonet connectors are keyed so the bulb can only go one way. Also, most LED lights use a current regulated power supply. It's not just an LED in there. The most energy efficient reverse polarity protection is a diode across the DC input. But it will trip a breaker if polarity is reversed. Another type is a diode bridge at the input but this has about 1V drop and thus wastes some power. Because of these factors not all LED lights have polarity protection but most do.
|
|
|
10-04-2014, 21:39
|
#10
|
Registered User
Join Date: May 2011
Location: Lake Ont
Posts: 8,582
|
Re: LED Polarity
Quote:
Originally Posted by transmitterdan
...Because of these factors not all LED lights have polarity protection but most do.
|
I expect (hope) that all LED bulb/assembly/fixtures intended for boat nav lights bloody well better be able to withstand a reverse voltage of at least 12v, because over their lifetime they will likely be exposed to many times 12v from static due to mishandling, mast raising/lowering, accidental reversal, and induced voltages from atmospheric phenomena. I believe some of the first crop of LED marine lights had embarrassingly short lives because the makers skimped on such protection.
|
|
|
10-04-2014, 21:56
|
#11
|
Moderator

Join Date: Feb 2011
Location: SF Bay Area
Boat: Islander 34
Posts: 5,480
|
Re: LED Polarity
The better LED bulbs are actually not polarized which is really sweet. I always try to make sure the max. bulb voltage is 25-30V. I've found that a 15V max voltage is not quite high enough, least wise for my first anchor light which used a DR. Led blub.
YEs go ahead and reverse the wires. If the bulb does not light then you have other problems.
|
|
|
11-04-2014, 04:38
|
#12
|
Moderator Emeritus

Join Date: May 2008
Location: Fort Lauderdale, FL
Boat: 48 Wauquiez Pilot Saloon
Posts: 5,972
|
Re: LED Polarity
Quote:
Originally Posted by sailorchic34
The better LED bulbs are actually not polarized which is really sweet. I always try to make sure the max. bulb voltage is 25-30V. I've found that a 15V max voltage is not quite high enough, least wise for my first anchor light which used a DR. Led blub.
YEs go ahead and reverse the wires. If the bulb does not light then you have other problems.
|
+1
__________________
In the harsh marine environment, something is always in need of repair...
Mai Tai's fix everything...
|
|
|
 |
Thread Tools |
Search this Thread |
|
|
Display Modes |
Rate This Thread |
Linear Mode
|
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
|
Advertise Here
Recent Discussions |
|
|
|
|
|
|
|
|
|
|
|
|
Vendor Spotlight |
|
|