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DIY Halogen to CFL conversion | by ukespresso
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DIY Halogen to CFL conversion

If you're not confident working with electricity then please STOP here.


You take full responsibility for your own actions if you follow any of these steps and are fully aware of the risks.


What you'll need:


1. 45/ 50W 5400k CFL bulbs, ideally with a CRI > 90 (954).

2. ES (E27) lampholder

3. A few tools: drill with HSS bit, hacksaw blade and file, screwdriver, electrical cable, heat shrink, scissors.


The steps:


1. The halogen site light, lampholder and CFL bulb are shown in photo ONE.


2. Undo the external retaining screw, remove the glass from the door, the inner relfective shield and the halogen lampholder, as shown in photo TWO.


3. Flip the light over, undo the screws in the electrical box, loosen the screws and remove the cables to the halogen bulb lampholder, as shown in photo THREE.


4. If you're lucky your site light will be long enough to fit a CFL bulb and E27 lampholder inside the body of the light. Unfortunately mine was too small so I've had to resort to mounting the E27 lampholder externally.


Mark the position of the new lampholder on the side of the light (it makes the wiring easier if you do this on the same end of the lamp where the cables were removed from the junction box).


Be careful to not cut the hole to high as the slope of the side will mean the bulb will hit the glass in the door (if you keep the glass), as shown in photo FIVE (oops, that should have been labelled FOUR).


5. Now either drill lots of holes and use a hacksaw blade to cut out the hole, or use a jigsaw with an HSS blade. File the sides smooth with a metal file, as shown in photo FOUR.


6. Cut a length of electrical cable long enough to reach from the electrical junction box to the end of the new lampholder. Wire it into the electrical junction box into the connectors you removed the halogen lampholder cables from, and the other end to the E27 lampholder. Photo SIX.


7. Screw in a bulb and test it all works OK. Make sure the wiring is connected correctly and safely. Once you're happy it works undo the lampholder screws and put sufficient heatshrink on the cable to cover the lampholder and the cables that go into it (I used a combination of 50mm, 25mm and 10mm heatshrink). Reconnect the cable to the lampholder, position the heatshrink and shrink to fit with a heat gun.

Photo SEVEN.


8. Now cut a larger hole in the bulb end of the reflector and fit it into the light (I added some aluminium foil behind it as there are a few extra holes in it.


For safety I recommend using a rubber grommet on the new hole to prevent the metal thread on the bulb touching the body of the light. Depending on the E27 lampholder and the thickness of the grommet it is possible that the bulb may not screw fully into the lampholder and therefore not work. You'll have to judge this depending on the components that you have.


I didn't a grommet so used some electrical insulating tape on the edges of the new hole and also at the top of the thread on the CFL bulb.


Carefully screw the CFL bulb into the E27 lampholder until it is secure- mine is a pinch fit (you can see the black heatshrink on the lampholder). If it doesn't work when you test it tighten it up a bit more but be careful not to break the bulb. Photo EIGHT. There's no need to put the grille back on although I have in my photo.


A few comments:


Although the photo shows the two lights mounted horizontally I plan to mount them vertically - two high and two low. 50W CFL is about 250W in old money so this should give me up to 1000W per side (probably less as I'm not sure how true the equivalent wattage is).


Depending on how they work I'll also be adding some barndoors to them. Hopefully this will follow in part 2. I also need to sort out the seal between the door and the body as I have a bit of gap as the lampholder is a bit high so the top edge of the end of the bulb is close to the glass in the door. If the worst comes to the worst I'll put gaffer tape over the gap. Remember that the light won't be weather-proof any more unless you're careful to seal all the gaps, especially around the lampholder.


I'll be adding this to my blog with individal photos but for the present the write-up will be the same as this one.


Comments and suggestions welcome.


Remember: safefty first. If you're not confident DON'T do it.


p.s. My variable power Vivitar flash mod is here


p.p.s. and now as seen on :) (16.03.09)


UPDATE: 10th October 2010


I'm working on a much easier twin bulb version. I'll post photos soon.

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Taken on February 26, 2009