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27-08-2012, 11:22
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#1
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Moderator... short for Cat Wrangler

Join Date: Jul 2009
Location: San Francisco
Boat: Cal 28 Flush Deck
Posts: 5,559
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110v Lights to 12v / Removing Transformer
I think I have read some brief accounts of taking 110 halogen lights and removing the transformers and wiring them into the 12v system.
Has anyone done this?
If not, why not?
__________________
Sara
ain't what ya do, it's the way that ya do it...
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27-08-2012, 11:26
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#2
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Registered User
Join Date: Jul 2011
Boat: Bavaria 47
Posts: 172
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Re: 110v Lights to 12v / Removing Transformer
If the lamps are 12V it should be possible. However, the current in the wire will increase by a factor of 10, so you need to make sure they are thick enough. On the other hand, if you replace the lamps with LEDs, the current problem is neatly solved.
__________________
Nigel
Got a Bavaria? Want a Bavaria Forum? Click here!
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27-08-2012, 11:57
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#3
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Registered User
Join Date: Apr 2011
Location: Cruising the east coast and Bahamas
Boat: Pearson 422
Posts: 228
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Re: 110v Lights to 12v / Removing Transformer
Slight variation. IKEA sells LED lights for bookshelves. They call it the Inreda link: INREDA LED spotlight - IKEA
The lights are actually 12v and the set includes a transformer that converts the 110 to 12v. Throw away the transformer and you end up with 4 12V LED lights. Turns out one fits neatly inside the wood ring of most existing overhead lights and runs nicely off the switch in the wood ring. Just cut away the reflector and bulb assembly, wire in the LED fixture (polarity matters) and voila. The price has gone up some since we bought them about a year ago. But at 12.50 per fixture, it's still cheaper than conversion bulbs or new fixtures.
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27-08-2012, 19:11
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#4
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Moderator Emeritus

Join Date: Sep 2007
Location: Eastern Tennessee
Boat: Research vessel for a university, retired now.
Posts: 10,405
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Re: 110v Lights to 12v / Removing Transformer
12 volts will not be enough potential for bulbs rated at 120 volts. They will either be too dim if they are incandescents or not work at all if they are LED's .
If you do change out the bulb then you need to be concerned about the wire or the socket trying to carry too much current. For the same power (watts) a 12 volt bulb will draw roughly 10 times the current...if both are incandescents. If the bulbs are now 12 volt LED's and they draw 1/10 th or less the amount of current, then you will be okay since the wire and the socket is gauged for the same amount or less current.
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David
Life begins where land ends.
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27-08-2012, 19:13
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#5
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Registered User
Join Date: Dec 2010
Location: W Carib
Boat: Wildcat 35, Hobie 33
Posts: 13,500
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Re: 110v Lights to 12v / Removing Transformer
Quote:
Originally Posted by sarafina
I think I have read some brief accounts of taking 110 halogen lights and removing the transformers and wiring them into the 12v system.
Has anyone done this?
If not, why not?
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Its easy to rewire any fixture for 12V, just remove transformers/power supply and reroute wires as necessary. All you need is a switch (if applicable) and appropriately sized wires.
If the existing bulb is 12V then this should work just fine. If not, you will also need to swap out the bulb for one that works with 12V. Either a 12V halogen (which may be easier to find in the same form factor and connection type) or an LED.
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27-08-2012, 19:15
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#6
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Moderator Emeritus

Join Date: May 2007
Location: Ohio
Boat: Now boatless :-(
Posts: 11,580
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Re: 110v Lights to 12v / Removing Transformer
Quote:
Originally Posted by sarafina
I think I have read some brief accounts of taking 110 halogen lights and removing the transformers and wiring them into the 12v system.
Has anyone done this?
If not, why not?
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There must be a backstory here. Didja go to a swap meet or sumptin?
I bought a set of halogens I am planning to install as deck lights. Still debating whether to install them or give them away and get LED <sigh...>
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27-08-2012, 21:30
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#7
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Moderator... short for Cat Wrangler

Join Date: Jul 2009
Location: San Francisco
Boat: Cal 28 Flush Deck
Posts: 5,559
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Re: 110v Lights to 12v / Removing Transformer
No swap meet this time ; -)
I bought these goose neck little mounted flexible spots, with halogen bulbs, from Ikea. They have just been really nice in the vberth in the evening when we are reading. They look good, small profile, seem to be pretty much resistant to corrosion, they look like new after 3 years. Nothing I have found that is "purposed for" boats suit me nearly as well.
So I was just thinking, that maybe I could use these, but removing the transformer (110 to 12) and wiring them into the new electric system.
Sounds as if the bulb may be a problem.
But if there are 12v halogen bulbs with the same stems then maybe it could work.
Just reading what everyone here has to say!
__________________
Sara
ain't what ya do, it's the way that ya do it...
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27-08-2012, 21:51
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#8
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Registered User
Join Date: Oct 2007
Location: Hollywood, Fl.
Boat: FP Athena 38' Poerava
Posts: 4,028
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Re: 110v Lights to 12v / Removing Transformer
I did what Paperbird suggested about two years ago on my boat. They've been working great ever since. Chances are good that the wire sizing feeding your existing 115V lighting circuit system is going to be fine to power a few small LEDs at 7.5watts each. A simple test after install with your handy DC amp clamp meter will give you the load being carried on the feed wire and whether or not it is of appropriate size or not.
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27-08-2012, 21:53
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#9
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Registered User
Join Date: Aug 2005
Location: NSW Central Coast
Boat: Lagoon 410 (now sold)
Posts: 514
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Re: 110v Lights to 12v / Removing Transformer
A few years ago I bought a mains powered halogen desk lamp and converted it. It was a very simple conversion ...
Just hook the 12V into the output of the transformer. I actually left the mains power lead intact as well, but have never used it. You should just confirm that the globe is in a fact a 12V globe.
I agree with the comments about LEDs being far more efficient. At 50 watts it chews as much power as a fridge. But I did mine before the warm white LEDs were so easily available, and for occasional use when a bright focused light is needed I'm happy.
I think your globe life would be substantially reduced if you use it while the engine is running, as they are designed for just 12V, not a battery charging current.
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Steve
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27-08-2012, 22:22
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#10
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Registered User

Join Date: May 2011
Location: Miami Florida
Boat: Ellis Flybridge 28
Posts: 4,078
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Re: 110v Lights to 12v / Removing Transformer
It's funny how you get to know people on this forum. When I first read the post I thought what kind of nut job would want to do that. Why not just buy 12 volt lights? Then I saw it was Sara who did the post and I thought, Sara has a reason, she doesn't ask stupid questions. Sure enough, Sara has a good reason.
Now if it was Tellie, well that's another story. When are you coming down to Miami?
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Retired from Hopkins-Carter Marine Supplies
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27-08-2012, 22:32
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#11
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Registered User

Join Date: May 2011
Location: Miami Florida
Boat: Ellis Flybridge 28
Posts: 4,078
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Re: 110v Lights to 12v / Removing Transformer
Sara, If you wanted to try LED lights, Suncor makes a mounted gooseneck 3 or 9 LED lamp. Might not be as pretty as the Ikea.
9 Star Cluster w/ Stalk
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Retired from Hopkins-Carter Marine Supplies
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28-08-2012, 09:05
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#12
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Registered User
Join Date: Dec 2010
Location: W Carib
Boat: Wildcat 35, Hobie 33
Posts: 13,500
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Re: 110v Lights to 12v / Removing Transformer
Quote:
Originally Posted by sarafina
....
So I was just thinking, that maybe I could use these, but removing the transformer (110 to 12) and wiring them into the new electric system.
...
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What is the voltage output of the transformer (should be printed on it)?
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28-08-2012, 10:21
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#13
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Registered User
Join Date: Oct 2007
Location: Hollywood, Fl.
Boat: FP Athena 38' Poerava
Posts: 4,028
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Re: 110v Lights to 12v / Removing Transformer
Quote:
Originally Posted by HopCar
It's funny how you get to know people on this forum. When I first read the post I thought what kind of nut job would want to do that. Why not just buy 12 volt lights? Then I saw it was Sara who did the post and I thought, Sara has a reason, she doesn't ask stupid questions. Sure enough, Sara has a good reason.
Now if it was Tellie, well that's another story. When are you coming down to Miami?
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Hey!!!! Was that a shot!?  Now I'm coming down for far more nefarious reasons
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28-08-2012, 11:29
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#14
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Moderator... short for Cat Wrangler

Join Date: Jul 2009
Location: San Francisco
Boat: Cal 28 Flush Deck
Posts: 5,559
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Re: 110v Lights to 12v / Removing Transformer
Now my mind is getting scary creative...
Imagining splicing 12v into the wiring between the inline switch and the light, with an inline switch on the 12v line as well. If the 12v was 'on' and the 110 was 'off' it should run on 12v, ther other way around it would run on 110.
The transformer steps the power down to 12v, so why do I need to change the bulbs? And I just looked, the bulbs are LED, NOT HALOGEN!
specs from ikea
Energy consumption: 3.0W.
Built-in LED light source.
May be completed with other lamps in the same series.
Light color; warm white (2700 Kelvin).
LED life time approx. 20,000 hours.
Could it be possible to have lights that run on shore power at the dock, and on batteries on the hook?
This seems to easy, there must be a hang up I am not seeing...
And yer right Hop, them is UGLY lights ; -)
But thanks for the vote of confidence that I'm not totally blonde! Much appreciated... Next time Himself is actin all doubtful about one of my plans I'll show him your post!!
__________________
Sara
ain't what ya do, it's the way that ya do it...
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28-08-2012, 12:50
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#15
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Registered User
Join Date: Aug 2011
Location: Petersburg, AK
Boat: Outremer 50S
Posts: 4,229
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Re: 110v Lights to 12v / Removing Transformer
Quote:
Could it be possible to have lights that run on shore power at the dock, and on batteries on the hook?
This seems to easy, there must be a hang up I am not seeing...
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As long as you have the inline switch on the battery powered side I think you have it covered. Without the switch, when you run it on shore power the little power supply in the light will try to power the whole boat, and that could be a bit of a problem.
Since they're cheap, and since they're intended to run off the included power supply, I would presume that IKEA has not included any voltage regulation circuits in the fixture, which means the LEDs could die an early death if you run them at 14.4V while charging the batteries. How early? The cost is not so high that it prevents finding out by experiment. Maybe report your results?
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