Current Draw of 12v WS2811 5M Strip

[Obejohnknobe]

Hello all,

  I am trying to get the correct power supply/s amperage to go with my 16 - 5M WS2811 pixel strips.  I have looked at several vendors websites selling the light strips and they have the wattage (14.5W but does not say if this is per meter or 5 meters) but no average or max current specs.  Can anyone assist, please?

 

Thank you in advance!

John M.

[Mr. P]

Divide the watts by the voltage and it will give you the amps.

W/V=A

FYI: most ws2811 5m strips at 30 leds a meter for a total of 150 averge 36w per strip.

Edited August 4, 2017 by Mr. P

[k6ccc]

Most strips that are 30 LEDs per meter are ABOUT 36 watts total for a 5 meter strip.  Strips that are 60 LEDs per meter are ABOUT 72 watts for a 5 meter strip.  That makes it about 3 amps and 6 amps respectively at 12 volts.

14.5 watts is pretty low for a 30 LED per meter 5 meter strip, but very close for a 60 LED per meter strip if they are talking about watts per meter.  If you post a link to the strips that you are looking at, we can take a look and sanity check the numbers.

 

[Obejohnknobe]

Jim,

Thank you for responding so quick!  Here is one of many websites I have encountered that gives some information about the WS2811 current draw http://www.ledlightinghut.com/ws2811-ic-intelligent-led-strip-light.html.    It seems no matter where I go the info is different as well as the different WS2811s on a 5M strip.  Some have 32-5050s per meter, some have 28-5050s per meter and so on.  The following is what I have purchased over a year,   Thanks!  John

Programmable Dream Color WS2811 LED Strip

Dream color ws2811 LED strip , 30LEDs/Meter ,  5meters/roll or according to customer requirements

1 WS2811 IC control 3 LED Chip

Product Specification:

 

Description	Multicolor ws2811 LED strip
FPC Width	10mm, better heat dissipation and longer life span
LED Type	5050 SMD
LED Quantity	30LED/m 1 WS2811 IC control 3 LED Chip
Power Consumption	10.0W/m
Grey scale	256/color
Working Voltage	DC 12V
Beam Angle	120 degree
FPC Color	White
Available Color	Full color
IP Grade	IP67(Tube Waterproof)
Operating Temperature	-20~+45 degree
Packing	5meters/Roll

[Obejohnknobe]

Hi Jim,

It seems I can have two -30 amp, 360 watt power supplies to power 16 strands (8 strands per power supply) of the pixel lights with some amps and wattage left over?  Correct?

John

[k6ccc]

The one you gave the link for is a 5V strip with a control IC for each RGB LED.  This means that every single RGB LED is fully and independently controllable.  This is generally the case with 5V strings or strips.  I have personally never seen a 32 pixel per meter strip, but there is no reason that it can't be done (and obviously someone did).  Their 10 watts per meter would be 50 watts for a 5M reel, which is not overly far from my general rule of thumb when you include the extra LEDs per meter.  At 5 volts, that would be about 2 amps per meter.

The strip that you posted the specs in the previous post is a 12V strip with a control IC for every three RGB LEDs.  This means that each group of three RGB LEDs is controllable as a group, but each group is fully and independently controllable.  This is very common for 12V strips.   There are 12V strips that have each pixel controllable, but as a general rule of thumb, they waste quite a bit of power to accomplish it.  Their 10 watts per meter is a little high, but not overly so.  At 12 volts, that would be a little under 1 amp per meter.

Both of those strips have a waterproof rating of IP67, which means that they can be left out in the weather (I have IP67 strips that have been permanently installed in the weather for at least five years.

 

[k6ccc]

3 minutes ago, Obejohnknobe said:

Hi Jim,

It seems I can have two -30 amp, 360 watt power supplies to power 16 strands (8 strands per power supply) of the pixel lights with some amps and wattage left over?  Correct?

John

I assume that is a 12 volt power supply.  At 36 watts per strip, eight strips strips would be 288 watts.  At 50 watts per strip, eight strips would be 400 watts.  Now the thing to remember is that the listed power load is based on all pixels at full white.  Seldom would you have all 16 strips at full white on all pixels (that is a massive amount of light).  You would likely get away with two 360 watt power supplies, but it's something you might want to remember during sequencing.

 

[Obejohnknobe]

Thank you Jim!

Yes, it is at 12v.  The full white is never in the specs for these lights and have to be asked about.  I really appreciate the info as I would be still digging up odds and ends of research leading me astray.  I do have a couple of sequences that have 16 strands at full white but it is for a couple of seconds (beats).  I do have extra power supplies that I can separate them into 5 strands per power supply (last one has 6).  I do overkill on just about everything when it comes to electrical and electronics.  Better safe than sorry.

Thank you!

John

[OzAz]

also remember, that unless you're using very high quality power supplies you should try and stay under 85% of the maximum rated output. eg a 12V 350W power supply you should try for no more than about 297.5W of load.

If you are close to the limit, consider running the controller at less than 100% brightness, or use less than 100% brightness in the sequencer, especially when using all white.

It can be handy to have a spreadsheet with all your props in it to work out power requirements etc, attached is a sample one with some sample data: 

power calculator.xls