Jump to content

lights


Featured Posts

Hi Richard.

 

B & Q and other D I Y places sell a hole cutter of the required size that even has a fancy contraption that catches all the dust. They are normally used for plaster ceiling but I know they work equally well with other materials.

 

Cut through the insulation too, as far as you can and finish off with a Stanley knife so you have a neat hole through to the metal. You can then undercut the insulation to give a larger space if you are are concerned about heating, cut a strip of thin aluminium the same width of the insulation and about 14 inches long. Roll it into a cylinder and push it into the aperture so it expands into place. You could probably do a similar thing with Bacofoil but make sure it can't touch live contacts.

 

There is a vast range of the lights manufactured but few retailers stock anything like all of them. Wattage goes from 5 to 50 but I wouldn't go above 20w on a boat they are just too bright. There is also an option of beam divergence (spot / flood) 10 deg (narrow) up to 45 deg (flood), again few shops bother to stock a good range.

 

One tip. These lights are rated at 12 volts, as you know when the engine is running the volts can reach close to 14 and Tungsten halogen lamps are intollerant of over voltage. Wire you downlights with say 1.0 mm cable to give a little volt-drop the lamps will last a lot longer.

 

These downlights are very clever. originally designed for display lighting some years ago they use a 'diachroic' reflector which allows the red (hot) end of the spectrum to pass right through it. That's why you need to be a little bit carefull about what is behind, but there is not that much energy.

 

John Squeers

Edited by John Orentas
Link to comment
Share on other sites

thanks John

By cutting the sprayfome out above the lights it is not going to get condensation dripping on the electrics is it.?

 

Hi Richard, I'm also fitting similar lights and wondered how you ran cable to each light, I have a central trunk cable running to 4 downlights (at each corner of a square). Did you just use ducting to each light (to avoid the foam vs PvC problem) or different cable, or even just duct tape over the PVC?

Link to comment
Share on other sites

Stuart.

 

The PvC problem applies only to it's use with polystyrene insulation, Richard has had his interior 'Sprayfoamed' so I don't think there is a problem. If you have polystyrene fitted there are several ways around the problem.

1/ I used silicon insulated cable where it contacted the insulation, butyl rubber is another option.

2/ Sleeving can be bought cheaply, or as you say wrap it in duct tape.

 

John Squeers

Link to comment
Share on other sites

Stuart.

 

The PvC problem applies only to it's use with polystyrene insulation, Richard has had his interior 'Sprayfoamed' so I don't think there is a problem.  If you have polystyrene fitted there are several ways around the problem.

1/  I used silicon insulated cable where it contacted the insulation, butyl rubber is another option.

2/  Sleeving can be bought cheaply, or as you say wrap it in duct tape.

 

John Squeers

 

Of course typical spray foam is polyurethane rather than extruded polystyrene insulation sheets.

 

I agree that cheap flexible sleeving will do the job as long as its not PVC !!

Link to comment
Share on other sites

Hi Richard

 

Just a little piece of info, that may be of help to you and others. If you find that you have a problem with lamps blowing due to excessive voltage you might find the following helpful. My friend had this problem with his 24volt lighting system, he found that his lamps were only lasting a very short time, due to the fact that his domestic voltage was running at 27volts, which is normal on a new boat with new batteries and connected to a land line through a multi inverter. Originally he was told that he would have to suffer this until his batteries became less efficient. However he discovered that some manufacturers produce lamps for a 27volt supply especially for this reason as they were aware that a problem existed with caravans and boats. I think for 12volts they are rated at 13.5 volts. He changed all his bulbs and the problem was cured.

 

Colin

Link to comment
Share on other sites

ive found a DC-DC converter 20-30 volts in and 24volt out with this i can run all the lighting circuits.

The other point is i dont think i will have the lights on with the engine running very often.

And as yet i have not ruled out the led ones as the manufacture says he has a d/barge and uses them on that he also says i can wire 2 together and use 24v and will need 10 in a room 13' x 6' that means all 10 in the lounge will take 10w in stead of the 120 i will use with conventional ones

Ime getting 2 to try to see what light they through out

Link to comment
Share on other sites

(The other point is i dont think i will have the lights on with the engine running very often.)

 

I would agree, I don't think I will have them on with the engine running very often.

 

However, I don't know about you but if I have the opportunity to cock something up I seize it with both hands, eventually. :(

 

Richard

Edited by Rick
Link to comment
Share on other sites

  • 2 months later...
Hi all

How do you fit the downlighters in the roof, they say they need 4'' clearance, that is not a problem in itself but do i remove the insulation above them.

And what whattage bulbs do you use.?

 

 

I was talking to an electrician on site about 12V downlighters, and about the 4" clearance, he warned me not to fit them as you shouldn't insulate between them! If they're household bulbs, they are designed to recess into a ceiling, where there will be sufficient airflow around the back of the bulb. Any insulation will hamper this flow, causing the bulb to keep blowing. And the thought of you just cutting a small hole into the sprayfoam is making me cringe with possible fire hazards. It might be possible to source different bulbs that'd work, not sure.

I've decided to use 12V kitchen downlighters that are designed to fit under wall cabinets. They come in their own casing(so designed not to get hot) that is surface mounted - seen some stainless steel triangular ones!

 

Clive

Link to comment
Share on other sites

I keep forgetting this is my first fit-out, I'm used to fitting out houses! I'm still sure that the bulbs will need rear ventilation (oo-er missus), isn't that what the 4" is all about (done it again!) ?

The downlighters I mentioned go up to 60W, so less bulbs needed, I thought.

Link to comment
Share on other sites

Clive.

 

20 watt tungsten halogen down lighters are as much as you will ever need on a boat but don't totally ignore the rear space issue, as I have mentioned before the reflectors on these fittings are invariably diachronic, which means the red (hot) end of the spectrum passes through to the area behind.

 

You will need less light generally on a boat, low ceilings etc. Inverse square law and all that.

Edited by John Orentas
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.