LED strip power supply

[wdariusw]

Hello. I have 16pcs 9.6W/m led strips. I want to connect all strips in parrarell. What power supply i need ? 160W ?

 

[Harald Kapp]

16*9.6W=154W, so 160W sounds o.k. at first. But note that the power requirement is in W/m. Therefore you hav et otake into account the length of the strips, e.g.:
at 1/2m the power required is 80W
at 2 m the power required is 320W

 

[wdariusw]

It is for my stairs lighting - 16 steps 1m wide

 

[(*steve*)]

you may find that for step lighting that you want to operate them at reduced intensity.

This will also yield a much longer lifetime.

Assuming these have integral resistors you'll be able to connect them all up in parallel.

get a power supply which allows you to adjust the output voltage. This will allow you to set an appropriate brightness

 

[wdariusw]

you may find that for step lighting that you want to operate them at reduced intensity.

This will also yield a much longer lifetime.

Assuming these have integral resistors you'll be able to connect them all up in parallel.

get a power supply which allows you to adjust the output voltage. This will allow you to set an appropriate brightness

Better price is for fixed output voltage (in my country 26eur for 180w 12V 15A) . What would be best way to reduce intensity with that power supply ?

 

[(*steve*)]

Often the fixed output power supplies have an adjustment to trim their output. If the one you get has this you may be able to reduce the output to maybe 11V. This doesn't sound like much, but it will reduce the current to the LEDs significantly.

If not, it may be possible to modify the power supply to reduce the voltage, but unless you know what you're doing, that way lies dragons.

 

[BobK]

Or you can place a PWM controller between the 12V power supply and the LED strips.

Bob

 

[Colin Mitchell]

You only need a short length for each step (20cm) and the LEDs should be 1 watt per metre.

 

[(*steve*)]

"should"?

possibly useful if the OP didn't already have the strips.

 

[Colin Mitchell]

5m of LEDs cost $3.00 post free on ebay.

I will send him a deposit of $300 so he can buy a strip.

 

[wdariusw]

Ok...i have bought 4w/m led strip. As i said, i will use about 1m led strip for each step (16 steps) . So there will be about 64W . Also, i will use dimmer for intensity regulation. Now thinking about proper power supply. What is better, constant current or constant voltage ?

 

[Colin Mitchell]

You only need 20cm per step.
You only need 10 to 15 watts total
Use 12v supply and add 100R for each 20cm.
Use a 12v 1 amp switch-mode plug pack.

 

[wdariusw]

You only need 20cm per step.
You only need 10 to 15 watts total
Use 12v supply and add 100R for each 20cm.
Use a 12v 1 amp switch-mode plug pack.

I will use 1m (not 20cm ! ). Why i should use 100R resistance for 12V led strip if i will use dimmer ?

 

[Colin Mitchell]

I have 10w to light up 5m of passage and the LEDs are far too bright to look at.

LEDs wash out your eyes.
They have to be very dull for a staircase.

I am just trying to make your installation as simple as possible

 

[(*steve*)]

Adding extra series resistance will reduce the peak current.

I would connect one string of 1m of LEDs and determine the current/voltage required to get them to the desired brightness. From this you can calculate if your power supply is sufficient.