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Old 29-01-2015, 04:27   #1
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What's causing flickering 12v light?

Got a 12 volt, 5 watt, flourescent light on board that keeps flickering whenever I turn it on. It will flicker and sometimes go on, sometimes not. Once on, the bulb will stay lit.


If I put a new bulb in, I get a similar problem, so it seems that the problem is in the connection to the bulb.

Where/how exactly should I look for the problem?

All advice greatly appreciated.

G2L
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Old 29-01-2015, 04:48   #2
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Re: What's causing flickering 12v light?

I seem to remember that if you have pos/ reversed this May happen, also put a tester on the terminals and make sure you are on full 12 v as when my voltage got below they would flicker,
No expert just my experience from memory
Option 2
Replace the fitting and lamp with LED !


Sent from my iPad.......i apologise for the auto corrects !!!
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Old 29-01-2015, 04:57   #3
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Re: What's causing flickering 12v light?

- Try cleaning the pin contacts on the bulb, if it's a tube, and also cleaning the connections from the fixture to the wires feeding it.

- If that's not the problem then perhaps the switch is failing?

- It could be the "starter" in the fixture is failing.

You can get replacement LED's to fit any fixture or device. They even make "tube" LED's to replace similar shaped flourescent tubes.

Dr. LED is way over priced.
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Old 29-01-2015, 05:23   #4
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Re: What's causing flickering 12v light?

Quote:
Originally Posted by Hoofsmit View Post
I seem to remember that if you have pos/ reversed this May happen, also put a tester on the terminals and make sure you are on full 12 v as when my voltage got below they would flicker,
No expert just my experience from memory
Option 2
Replace the fitting and lamp with LED !


Sent from my iPad.......i apologise for the auto corrects !!!
Thank you for you input. I know that I have a full 12v on the system. May not be getting to the bulb due to wire corrosion, or as one poster noted, dirty connections. Could also have polarization reversed, as I have certainly inherited worse problems on this boat : )

Will check the various possibilities.

Regards,

G2L
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Old 29-01-2015, 05:26   #5
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Re: What's causing flickering 12v light?

Quote:
Originally Posted by PDA1 View Post
- Try cleaning the pin contacts on the bulb, if it's a tube, and also cleaning the connections from the fixture to the wires feeding it.

- If that's not the problem then perhaps the switch is failing?

- It could be the "starter" in the fixture is failing.

You can get replacement LED's to fit any fixture or device. They even make "tube" LED's to replace similar shaped flourescent tubes.

Dr. LED is way over priced.
The bulb is a fluorescent tube. Will check and clean up the connections as suggested.

Thanks for your help,

G2L
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Old 29-01-2015, 05:45   #6
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Re: What's causing flickering 12v light?

The referenced "starter" in the fixture is called a ballast. Learn how fluorescent lamps work (Google "How things work" or wikipedia) and go from there.
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Old 29-01-2015, 06:34   #7
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Re: What's causing flickering 12v light?

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Originally Posted by Stu Jackson View Post
The referenced "starter" in the fixture is called a ballast. Learn how fluorescent lamps work (Google "How things work" or wikipedia) and go from there.
Well, there are starters and there are ballasts. A starter is a metal canister about the diameter of a nickel and an inch long that's visible from the outside of the fixture and can be replaced by turning it to the left about an eighth of a turn. Starters in florescent fixtures are pretty rare these days. Most lamps are self starting.

The ballast is a type of transformer and is contained inside the fixture. You have to remove a cover to get to it. The cost of a replacement ballast is usually close to the cost of a replacement fixture.

On a boat, before I spent a lot of time and money repairing a florescent light, I would replace the entire thing with an LED fixture and enjoy the low current draw and reliability.
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Old 29-01-2015, 07:39   #8
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Re: What's causing flickering 12v light?

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Originally Posted by rwidman View Post
I would replace the entire thing with an LED fixture and enjoy the low current draw and reliability.
Alternately, keep the fixture and wire in a couple of passes of flexible strip LED lights. I have seen several of these done when the fluorescent lights went bad and they worked out remarkably well. Better than the original, IMO.

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Old 29-01-2015, 08:40   #9
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Re: What's causing flickering 12v light?

Quote:
Originally Posted by Gone2long View Post
Got a 12 volt, 5 watt, flourescent light on board that keeps flickering whenever I turn it on. It will flicker and sometimes go on, sometimes not. Once on, the bulb will stay lit.


If I put a new bulb in, I get a similar problem, so it seems that the problem is in the connection to the bulb.

Where/how exactly should I look for the problem?

All advice greatly appreciated.

G2L
Typical of a failing but not quite dead ballast. Replacing a ballast isn't worth the time/cost (DTDT). As an alternative, cut it out and replace the florescent tube with an LED tube such as the MarineBeam Tube

We recently installed 4 of these (in warm white) in our failing overhead recessed lighting fixtures and have been really happy with the conversion. More and better light and much less energy consumption.

FWIW...
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Old 29-01-2015, 14:31   #10
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Re: What's causing flickering 12v light?

I go with failing ballast. Classic symptoms. As others have said... just rewire with LED strips or install whole new LED fixture. Better light, longer life, lower current.


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Old 29-01-2015, 20:17   #11
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Re: What's causing flickering 12v light?

Agreed bad ballast rep,ace with a dedicated led fixture here is what we replaced ours with Optronics 18 LED Double Dome Light 12V Interior Cargo camper RV Trailer White V1 | eBay made us a deal on a large quantity of these and the single ones he sells as well
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Old 29-01-2015, 20:24   #12
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Re: What's causing flickering 12v light?

I got a new marinebeam fixture. LED Very nice, less than half the draw of the old one, nicer, too, get warm white. ...but you know that already from reading all the LED topics, right? :fa cepalm:
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Old 29-01-2015, 21:46   #13
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Re: What's causing flickering 12v light?

I've binned our fluoros now. Leds uae less power, have better light output and aren't fussy on how much DC voltage you give them.

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Old 29-01-2015, 22:09   #14
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Re: What's causing flickering 12v light?

Most 12v LEDs I have found will put out basicly the same light all the way down to 5 volts or so
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Old 29-01-2015, 22:51   #15
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Re: What's causing flickering 12v light?

Gone2long:

Just a little suggestion: you might want to edit your avatar, to show your boat, and your general area; it makes it easier -- for those of us who look at them -- to tune our advice to your location.

Ann
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