Alternative transformer for LED

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Luka3791

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My partner bought 8 7 Watt LED recessed ceiling lights for our new living room but didn't realise they didn't come with a driver. On further investigation the recommended dimmable drivers from the same manufacturer are around £90 each:
Astro 1756 HEP 350mA LED CC Dimmable 1-10V Driver
350mA LED Driver for 12w LEDs.

I presume I would need one for each light which adds £720 to the cost. This seems incredibly expense in relation to the lights which were half that price and to other drivers on the market.

The problem is I can't work out what a suitable cheaper alternative would be as they all seem to be specified in different ways.

Any advice appreciated.

Thanks
 
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I'm afraid that if you go with that solution your expense won't stop there - that's a 1-10V dimmer, i.e. it is not controlled by a normal dimmer switch, you have to supply the driver with a control voltage which you vary from 1 - 10V to control the brightness.

screenshot_366.jpg


http://en.wikipedia.org/wiki/0-10_V_lighting_control

Basically you need to find a dimmable driver, or drivers, which can cope with the load of your lamps and works off a normal dimmer switch.
 
Thanks for the replies.

If I forget the dimming option can you recommend a cheaper alternative to this which is their recommended non-dimming driver but still £32 a go and I need 8 of them?

Astro (1735) LED Driver 350mA 12W Constant Current

Thanks
 
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I think there is a big problem with marketing you need a true driver that's a device which controls current. Where often power supplies are labelled driver when they control voltage.

One can use voltage regulators to control current
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but you will be producing quite a lot of heat for 350mW at 5v = 1.75W. Clearly the whole idea of using LED's is to reduce heat.

At 7W and 350 mA it will need 20 volt and that seems some how wrong. Most LED's white are around 3 volt which would require 2.3 amp it may be each lamp already has 9 LED's in it at 350 mA each?

Running 9 LED's in series means if one fails either all fail or all left are overloaded so would soon fail anyway.

I think I would prefer a 230 volt lamp where all the control is built into the lamp.

As to dimming well unlike tungsten colour does not change so rather pointless better to have it in banks with more or less banks rather than dimming every bank.
 
ericmark said:
I think there is a big problem with marketing you need a true driver that's a device which controls current.
Click to expand...
Which is what the one proposed by Astro is. It's just an expensive one.

Or is it? How much should a good quality constant-current 1-10V dimmable LED driver cost?

Why don't they sell a non-dimmable one?


At 7W and 350 mA it will need 20 volt and that seems some how wrong.
Click to expand...
Why? If power is 7W and current is 0.35A the the voltage must be 20V. It has to be - other values would not work, so it must be right.

And 20V is in the range which that driver puts out.

screenshot_368.jpg


Bad typography - it's actually saying 3 - 30V, not 3.30V.

And it all ties up - it will drive up to 9 or 10 LEDs, each around 1 - 1.2W at the expected voltage per LED and a current of 350mA.

The manufacturer's spec says 1 - 9 at 1.2W.


Most LED's white are around 3 volt which would require 2.3 amp
Click to expand...
Not if the individual LEDs are in series inside the lamp package. Which clearly they must be (assuming Astro know what they are talking about), or a constant-current driver would be useless.


it may be each lamp already has 9 LED's in it at 350 mA each?
Click to expand...
That would be 9.5W. It's a 7W lamp, so it must be 6 or 7 LEDs.


Running 9 LED's in series means if one fails either all fail or all left are overloaded so would soon fail anyway.
Click to expand...
If they fail open circuit then yes - one goes and the whole lamp goes out. If they fail closed circuit then the lamp gets a bit dimmer but the constant current driver will ensure that the remaining ones are not overloaded.


I think I would prefer a 230 volt lamp where all the control is built into the lamp.
Click to expand...
But what would you want the control do be doing internally?

Constant current for a bunch of LEDs in series, or constant voltage for a bunch in parallel?

Or a single high-powered emitter, e.g. Luxeon?
 
Luka3791 said:
If I forget the dimming option can you recommend a cheaper alternative to this which is their recommended non-dimming driver but still £32 a go and I need 8 of them?
Click to expand...
Hopefully someone can.

Do remember though that it's got to be good quality, and if you go too cheap, e.g. some Chinese tat on eBay or Amazon not only might it not be safe but it might drastically shorten the life of your lamps.
 
This is an 11W driver which will do 1 of your lights:
http://cpc.farnell.com/powerpax/led-dr-350-12/led-driver-350ma-11-2w-cc-32v-max/dp/PW03094

Or you could get two of these and run 4 lights from each, the 4 lights wired in series:
http://cpc.farnell.com/powerpax/led-dr-350-60/led-driver-350ma-49w-cc-140v-max/dp/PW03099

There are other ratings including a 28W which in theory would do 4x7W, but that would mean running at the maximum rating of the driver, not recommended.

The key specifications are that it must be 350mA, and the total rating more than the light(s) you intend to connect to it.
 
ban-all-sheds said:
Luka3791 said:
My partner bought 8 7 Watt LED recessed ceiling lights for our new living room but didn't realise they didn't come with a driver.
Click to expand...
OOI, which Astro model were they?
Click to expand...

The model is Astro Asprilia 5693.

I'm not looking for the cheapest of the cheap just something more reasonable than £32 and £92 (dimmable) which I thought was a touch expensive.

Thanks for the suggestions.
 
Luka3791 said:
My partner bought 8 7 Watt LED recessed ceiling lights for our new living room but didn't realise they didn't come with a driver.
Click to expand...
They don't make that a secret....


TBH you've got a real dilemma, and I don't envy you.

I'm sure you can find a cheaper driver which is of good quality, but if you don't use "theirs" then if a light should fail, will they use that as an excuse to wriggle out of the warranty?

Those lights are nearly £60 each, and the lamps are not replaceable.....


If I were you I'd ask them about that.
 
Interestingly I just received the following from the Astro technical department.

It might be worth looking elsewhere on the market for a higher wattage driver that will power more than one fitting.

Please visit an electrical wholesaler and ask them for a suitable driver. You will need a 350mA constant current driver, 1-10V dimmable driver. Tell them that the forward voltage of a single Aprilia LED is 18.8vf.

This forward voltage figure will need to sit within the output voltage range of the driver that you choose and will determine the overall wattage of the driver chosen.
 
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