12V RGBs and wiring length

[RaceMedic]

Good morning everyone ...

I have looked for the answer in the search box with no luck !

I am converting my house over from c9 LEDs to 12v RGB strips this year with 2 controllers.

I was told that 18AWG would be sufficient .. what is the longest I can run the wire from the controller to the RGB strip without having power drop, especially at the distal end of the strip.

Thank-you for your time !

Dave

[Scott Cockroft]

Here is a link to an online calculator. You enter the voltage, spacing, and wire size. Then it will give you an ending voltage.

http://blinkyflashy.info/calcs/pixpower.php?psv=12&wl1=10&wl2=4&iwl=4.72&psa=50&wg1=22&wg2=20&iwg=20&wp1=3&wp2=1&np=150&pmx=60&pmn=&submit=submit

[RaceMedic]

Scott ..

Thanks ... WOW .. Confusing though .. a bit.

Any further assistance would be appreciated.

DEFINITELY have not seen this calculator before .. very useful.

Dave

[Scott Cockroft]

That calculator is really for pixel strings. This one might be better to figure simple voltage drop. http://www.supercircuits.com/resources/tools/voltage-drop-calculator

 

What I don't know is what an acceptable ending voltage is. The second calculator says less than 10% drop. However, you also need to figure something in for the voltage drop within the strip or string itself.

[edvas69]

If using 12vdc Strip which is rated at 3 amps for the 5 metre length and using 18 guage cable which has a resistance of 0.025 ohms/m for a 30 metre run (which is 60metres due to the return path) will give you approx 4.5 volts dropped before even going through the strip, this is too much voltage drop.

 

Try adding additional cores so you effectively 1/2 the resistance and thus volatge drop to approx 2.2 amps which may be enough to get way with

 

Refer to this thread on info regading voltage drop and the effects and how much you can get away with.

 

http://auschristmaslighting.com/forums/index.php/topic,3668.0.html

[Ken Benedict]

Here's another option for you; run 24-35 volts down your wire of choice, then just before your strip, insert a 24v-12v waterproof converter.

 

It will get you 12 volts DC at 5 amps all the time. But it's another $6.80 to add to the price of the strip. And you would need one per strip.

 

You would also need a 24 volt or 32 volt power supply.

 

I've used them and so have others on this forum, very successfully.

 

Something else to think about.

 

PS: They also make converters for 5 volt smart strips.

 

PPS: Or you could just bite the bullet and get a small PS with enclosure and put it right next to the strip. For an extra $24/strip.

 

 

See also: http://forums.lightorama.com/index.php?/topic/19936-diagram-for-5050-rgb-led-setup/?p=189465

 

and: http://forums.lightorama.com/index.php?/topic/21033-rgb-strings/?p=203789

 

and: http://forums.lightorama.com/index.php?/topic/19392-ok-questions-in-rgb-dmx-that-i-cant-seem-to-find-any-answers-to/?p=183334

 

and get back to us on your progress and solutions.

Edited June 26, 2013 by Ken Benedict

[RaceMedic]

Thanks Ken ....

 

Now I am more confused.  

 

This is the power supply that I bought ... http://www.aliexpress.com/store/product/350W-Dual-Output-Switching-Power-Supply-88-264VAC-input-12V-350W-output-CE-and-ROHS-approved/701799_289599951.html

 

Most of the runs will be a LOT less than the 30' ... those ones are just going to the high peak of the house.

 

 

Dave

Edited June 26, 2013 by RaceMedic

[Ken Benedict]

Too many options, I guess.

 

Buy this: http://www.ebay.com/itm/100-FT-16-AWG-GAUGE-ZIP-WIRE-RED-BLACK-STRANDED-COPPER-POWER-GROUND-/230922324357?pt=US_Car_Audio_Power_Speaker_Wire&hash=item35c40b0985

 

 

At 4 amps, it drops to 11 volts on a 30 foot run, which should be OK.

Edited June 26, 2013 by Ken Benedict

[edvas69]

At 30 feet not 30 metres you should be OK using 18 guage 12vdc strip. You would see around 1.5 volts dropped before the strip which shouldnt be enough to effect the strip as a 12vdc strip ussually sees issues at around 9.5 volts, so if the strip doesnt drop more than 1.5 volts itself then it will be OK

[CLD Kevin]

I'm not adding any technical ref like Eddy, Ken and rest...they have it covered. But for what it worth, I powered a 20ft basic (dumb) RGB strip that was 45ft away. I used 18awg waterproof pigtails on each side with 4-wire 18awg cable between. I also used a 30A PS going through the LOR DC board from my garage to the far right side if my house. The RGB strip was powered from one end through a 16ft strip and additional 4 ft strip inline making it 20ft long. Absolutely no issues at all. It was just as bright as the strip that was 5ft from the PS.

[RaceMedic]

Kevin ....

 

You mention 18 AWG pigtails ... I bought these ..

 

http://www.aliexpress.com/store/product/50-pairs-4-Core-White-Waterproof-Line-15cm-long-each-male-and-female/701799_323485474.html

 

The wire looks smaller than 18AWG .. would that cause an issue also ... I didn't realize they come in different guage wires !

 

Thank-you everyone for your help !

 

 

 

Dave

[edvas69]

I'm not adding any technical ref like Eddy, Ken and rest...they have it covered. But for what it worth, I powered a 20ft basic (dumb) RGB strip that was 45ft away. I used 18awg waterproof pigtails on each side with 4-wire 18awg cable between. I also used a 30A PS going through the LOR DC board from my garage to the far right side if my house. The RGB strip was powered from one end through a 16ft strip and additional 4 ft strip inline making it 20ft long. Absolutely no issues at all. It was just as bright as the strip that was 5ft from the PS.

 

What you find is that you will get more distance and less voltage drop if you concentrate on using either single colours or 2 mixed colours, When calculating the estimated voltage drop we always base the calculation on when the LEDs are White (all 3 colors on) as this is the maximum current that will be drawn. This will show voltage drop the most because you end up with a pinkish white colour which becomes more pronounced the further down the strip.

 

So one way to also over come this issue and gain longer distance is to drop your intensity levels to about 80% when using white as this will not be very noticable as the human eye does not see LED light in a linear fashion, so lower intensity levels at the higher end are less noticeable compared to that at the low end of dimming. LEDs Dim in a linear fashion, the human eys doesnt see in a linear fashion so this makes another good way to over come voltage drop and increase the max distance without any real noticeable effects and it doesnt cost anything.

[RaceMedic]

Out of respect for the neighbor across the road I was probably going to drop the max intensity anyways ... DEFINITELY NOW !!  

 

Dave

[CLD Kevin]

Kevin ....

You mention 18 AWG pigtails ... I bought these ..

http://www.aliexpress.com/store/product/50-pairs-4-Core-White-Waterproof-Line-15cm-long-each-male-and-female/701799_323485474.html

The wire looks smaller than 18AWG .. would that cause an issue also ... I didn't realize they come in different guage wires !

Thank-you everyone for your help !

Dave

I don't know what size gauge wire they use. I believe you can request different gauge wire.

I stock 18awg pigtails, but you already purchased them. Just follow Eddy's instructions and you should be fine.

[Little_b]

Just a quick question for you, I am planning on putting RGB strips on the different sections of the roof line.  Some runs are longer than 16ft, so I was planning on cutting a second strip to finish the runs, most are about 23 feet.  I am going to run the strip connectors to the middle and run the wire from the controller to both sections so I don't run into voltage drop.  So the question I have is: will the shorter length strip be brighter than the full 16ft strip?  Or so I need to cut 2 strips the same length?  I am using a 350 watt power supply with 2 RGB channels (6 Channels total) per side of the LOR DC controller with roughly 2 strips per color.