# Changing Dome Flourescent Lamps To LED



## listerdiesel (Aug 3, 2012)

I've got around to doing this modification today, and am quite pleased with the result.

Originally supplied with a 9W inverter-fed flourescent, they now have 4 X LED packages giving a better and brighter light spread at less current.

The difference can be seen in the following two pictures. First is the original single 9W tube, followed by the modified light. These were taken within seconds of each other, there are two lamps in the habitation area, I modified one to see what it was like and to do a comparison:



















The difference is fairly obvious, even in outdoor daylight conditions with a translucent roof.

To show how it was done, here are the stages:

First of all, the basic light with the cover taken off and the whole thing disconnected:










Next the tube and clips are removed:










Then the inverter and wiring are taken out, leaving just the on/off switch in place:










Next step is to mix up some Araldite Rapid, having first got your four LED's and connector block ready. We tried four around the edge first as it would probably give us a decent spread of light, and four is just a convenient number as we bought 10, used two on the spotlights and had 8 left over with two dome lights to convert.










The Araldite takes about 20 minutes to become handleable, don't rush it and wait until all the parts are firm. The LED's we stuck on the black plastic part of the pins so we could get them off again if we needed to.



















LED's are polarity sensitive, on our batch the negative pin was the one with the two through-holes above it, they are also marked on the other side with + and -.

Then you can wire them up. I used very thin tinned copper wire with a small PTFE sleeving over the top, and bent the +VE leg up in the air a bit so I could run the negative leads underneath:










Do a run all round and back to the switched side of the terminal block. On mine, I glued a 3-way block to the back of the light, the centre terminal is the negative, the terminal furthest away from the switch is the +VE input, the terminal nearest the switch is the output from the switch to the LED's.

Same thing for both terminals on the lights, so you end up with a double ring.










Once that is done you can apply 12V and check that they work.










Don't look at them directly for too long, they emit ultra-violet and will hurt your eyes if you stare at them for too long.

I have loads of the sleeving available, let me know if you need any, an SAE will get you sufficient to do a couple of lamps.

Peter


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## Zebedee (Oct 3, 2007)

Nice job Peter.

I did ours last year and apart from a much better and "nicer" light the current draw is a lot less even than a fluorescent. Handy when off hookup.

Dave 

P.S. What you didn't say (_but which might help others_) is that you won't blow the LED lights by trying the polarity and getting it wrong. One way nothing will happen - swap the wires and it will work. :wink:


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## listerdiesel (Aug 3, 2012)

Some will survive reversed polarity, some won't, it depends on the reverse voltage rating of the LED pack.

Generally it is always best to tell folks to go by the markings, especially those not as electrically savvy as you or I 

Peter


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## safariboy (May 1, 2005)

Looks a good modification. I have used LED strips to repair a linear fitting when the electronics blew. The light is better and the current less.

I was surprised to see your suggestion that these lights emit U-V is is actually quite difficult to get U-V from an LED. The fluorescent certainly does but it should be filtered out. Can you produce a reference? The spectrum I have seen cut off sharply at 400nm - the start of the U-V.


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## listerdiesel (Aug 3, 2012)

Might not be UV then but is certainly screws my eyes up and the camera doesn't like it either, blue lines down the viewfinder.

Peter

Edit:

Read this: http://en.wikipedia.org/wiki/Light-emitting_diode

Looks like my eyes might be right after all.


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## safariboy (May 1, 2005)

listerdiesel said:


> Might not be UV then but is certainly screws my eyes up and the camera doesn't like it either, blue lines down the viewfinder.
> 
> Peter


There are white LED's that use U-V LED's and a phosphor to get the white light. I thought that there were experimental only but perhaps I am wrong here.


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## Pudsey_Bear (Sep 25, 2008)

Does that mean we could get a tan, and not need the Vit D pills then if we leave the lights on :lol: :lol:


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## JockandRita (Jun 1, 2005)

> Kev_n_Liz said........Does that mean we could get a tan, and not need the Vit D pills then if we leave the lights on :lol: :lol:


 :lol:

Jock.


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## Stanner (Aug 17, 2006)

For my dome lights I used self adhesive panels like this...






Much easier to fit - no glueing or soldering needed just some connector strip to join the cut ends of the wires.


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## Pudsey_Bear (Sep 25, 2008)

http://store.ijdmtoy.com/90-LED-Car-Interior-Map-Dome-Light-Panel-p/sku93.htm


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## Stanner (Aug 17, 2006)

> http://store.ijdmtoy.com/90-LED-Car-Interior-Map-Dome-Light-Panel-p/sku93.htm


Can't remember where I got mine from but they cost about £1.00 each.


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## Pudsey_Bear (Sep 25, 2008)

> *"Stanner"*
> Can't remember where I got mine from but they cost about £1.00 each.


Sorry I thought you got them from the company in the youtube link, I just posted the url from there to the purchasing site, as not everyone might realise it was there.


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## Stanner (Aug 17, 2006)

> > *"Stanner"*
> > Can't remember where I got mine from but they cost about £1.00 each.
> 
> 
> Sorry I thought you got them from the company in the youtube link, I just posted the url from there to the purchasing site, as not everyone might realise it was there.


That's why I said "like" that and didn't post the link because that is a ridiculous price.

This is the actual type I bought with 48 LEDs, but still 3 times the price.

http://www.ebay.co.uk/itm/White-Car...S-Dome-Festoon-Bulb-Adapter-12V-/161133047931


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## Pudsey_Bear (Sep 25, 2008)

Ah I see, that is a good price, shame I don't have a use for those.

I jsut ordered some of these as they are just so handy to put in cupboards etc.

http://www.ebay.co.uk/itm/120954220880?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649


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## Stanner (Aug 17, 2006)

10 for under £10................ free P&P

http://www.banggood.com/10-X-Panel-...0-Dome-Bulb-BA9S-12V-DC-Adapter-p-916000.html


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