Par16 "Birdie" - Lamp and Power Supply

[PYROmaster]

Hey Folks!

I'm looking at using some birdies but just a little stuck on power for them.

I've bought the main unit and it is the 12/24v version with the GU5.3 socket.
As this is a common fitting I have bought some standard LED lamps off Amazon and it was interesting to just find out that they are 12v AC rather than what I assumed to be DC.

So, either - what transformers do people normally use to power these? - or - what lamps are available and people use?

Ideally I would like to operate as LED on 12v DC as I have a leisure battery powering the system I am using...

Also, what would you guys suggest for a dimmer? 

Thanks 🙂

[Yorkie]

I bought some 12V Sylvania LED MR11's intended for domestic use (AC as far as I could tell) and they worked just fine in a motorhome (from the 12V battery)

[alistermorton]

As Yorkie says, the AC lamps will work fine on DC, but you'll struggle to dim them. Most of them have a SMPSU which allows them to work over a range of voltages. Even PWM the power has no real effect.

[sunray]

My only real experimenting is with G4 and G9 sizes.

Generally G9's (230V) will not work on DC and if they don't say 'dimmable' generally they are not. They will generally dim down to around 50-70% then snap down to a glow.

G4 come in all sorts of arrangements; some are AC only or DC only, some have a constant current chip and will behave something like above. The really cheap versions tend to have a bridge rectifier, small capacitor and a resistor and will PWM dim down to around 10% then snap off. Bypassing all components the LED's do of course dim correctly on a PWM dimmer.

[alistermorton]

Birdies are likely MR16 or GU10 replacement. There are dimmable versions of these but they tend not to be what you'd call theatre dimming quality. 

[sunray]

Oh yes, a big difference between the standards.

[KevinE]

I've run them off DC supplies before now, however I remember some early led MR16's with the multiple led pcbs had half the led string on one half the mains cycle and half on the other, I suppose to simplify the dropping arrangements while avoiding flicker. Obviously these wouldn't work on your leisure battery but things have moved on a bit since then in the world of led replacements!

[Jivemaster]

The lamps in trade satisfy the requirement for light from low volts by any means that may or may not be DC suitable. Onsolar.co.uk specialise in lamps intended for use from DC, off grid, battery type applications. Whether they have something you can use.... Likely there will be other suppliers that I haven't found. 

[alistermorton]

Part of the problem, I think, is that the public perception of a dimmable lamp is very different to the theatrical one. For theatre, we want a smooth fade from completely off to completely on. For domestic and commercial use the ability to vary between about 20% and full is all that most people need. So the lamps are really for different markets. Hence why LED houselights, for example, are a specialist product.