Converting Floor Lamp Halogen to LED - Advice

[Jack Strong]

Hi,

Could someone please be able to give me some advice and electrical theory about converting a light from halogen to LED. The current circuit has 5 20W halogen bulbs running off a dimmer:

Buy Bella 5 Light Floor Lamp from the Next UK online shop - http://www.next.co.uk/g503008s1

I have read up on dimming LED's and considering the lights purpose I intend on just changing to just on/off.

I intend on using some existing COB LED's I have, which are 3W(something I bought before properly understanding LED dimming requirement). They are actually dimmable but thats not important.

Could someone please tell me what LED driver I need to run 5x 3W LED's ? The thing I dont understand is calculating the sum current draw.

I do know that the driver should be running at 80% capacity.

Also does anyone recommend a good website/youtube video for understand how to calculate electrical requirements for an LED circuit ?

Thanks for your help.

Jack

 

[telectrix]

G4 bulbs are 12V. just ditch the dimmer and bung the LEDs in

 

[1Justin]

If you wire them in parallel (The fitting will already be wired this way), current draw will be approximately 5x(3/12)= 1.25A. I would ditch the dimmer and fit a 12V DC LED driver able to supply that. Get one which can drive 5A and that should cover you.

But..do check your digital radios nearby - you might wipe out reception (just saying. These teeny LEDS without room for RF suppression and without any CE marking or test compliance are often let's say, lacking in this regard. )

Re dimming, the spec on those lamps is confusing. They say 12-30V AC/DC With a spec like that I'd expect them to contain a simple bridge rectifier and SMPS driver to supply the LED drive current. I find it hard to believe these would dim in any nice way since that requires a dimming method, and none is specified.
"RAW" LED's are dimmable with a DC variable current source driver, and "12V LEDS" contain internal drivers which can respond to an external PWM "dimmed" drive voltage. These seem to be specified in no way at all, whilst claiming to operate off a wide range of both AC or DC. That doesn't wash, and I suspect not actually dimmable, though if the manufacturer can enlighten us I'd be interested to know.

If your lamp contains glass covers for the halogens, don't fit them. Even if the LED's do fit inside they will definitely overheat if you fit the covers.