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Matt
12-31-2007, 06:15 PM
The question I get asked the most probably regards how much this costs in terms of electricity used. Do computerized displays really save that much power over a static display of the same size? What does your power bill look like?

-Matt

eschnell
12-31-2007, 06:46 PM
I think it would be less, because you are not using all the lights all the time, as compared to a static display.

Matt
12-31-2007, 06:50 PM
Exactly my thoughts. But do incandescent bulbs draw more current than normal when they turn on (I think there's a proper term for this, but I can't remember it)?

-Matt

Macrosill
12-31-2007, 07:15 PM
My electric usage added up to about 100.00 extra for the month of December last year. 23,000 lights. Not bad at all considering I pay one of the highest electric rates in the country, slightly over .21 cents per KWH when all the fees and surcharges are added. Still awaiting this years bill but I am not worried. Like you guys have said, its not static so it uses less electric than if it was static.

RJ
12-31-2007, 07:27 PM
The bill was about $40 more with the light show with about 22,000 lights.

acewingman
12-31-2007, 08:42 PM
People running static displays are not powering computers and circuit boards either...

I saw an episode of Myth Busters where they proved the incandescent light turning on does not use more power. However they did show that fluorescent lights use slightly more power to turn on...

ppohlman
12-31-2007, 08:49 PM
I saw that same episode. Basically they proved that it is cheaper to turn on and off a light instead of keeping it constantly on. That means that every time you turn off (flash) a strand of lights you're saving money compared to keeping it on.

acewingman
12-31-2007, 09:53 PM
You are correct sir. Every time you flash the bulb you are using an equivelent of .36 of a second of energy. So, if your bulb flashes 1000 times, you are using an equivelent of 6 minutes of energy. Meaning for every 1000 flashes, the light would have to be turned off for 6 minutes to have a cost savings.

Only makes sense that if the bulb is off there is a savings.

For startup energy consumption, Grant hooked up an inductive current loop to a computer and measured the amount of energy used when the turned on the bulbs. With an inductive current loop, you run a wire through the center, which induces a current in the loop. This current is then measured by a digital sampling oscilloscope.

Based on the amount of energy consumed turning on the bulb, they were able calculated how long the bulb would have to be turned off in order to make it worth the energy savings, i.e. "It's best to turn off the bulb if you are leaving the room for":

Incandescent: 0.36 seconds
CFL: 0.015 seconds
Halogen: .51 seconds
LED: 1.28 seconds
Fluorescent: 23.3 seconds

In other words, its almost always best to turn the bulb off. Even the 23 seconds for the fluorescent lights isn't very long, and the rest of the times are pretty much blinks of an eye.

Frankz
12-31-2007, 10:08 PM
You could always measure them yourself:
Kill-a-Watt (http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?jspStoreDir=hdus&catalogId=10053&marketID=401&productId=100396600&onlineStore=true&locStoreNum=8125&keyword=kill-a-watt&langId=-1&searchRedirect=kill-a-watt&storeId=10051&endecaDataBean=com.homedepot.sa.el.wc.catalog.bean s.EndecaDataBean%4063b1995&ddkey=Search)

.

rlilly
01-17-2008, 05:34 PM
But do incandescent bulbs draw more current than normal when they turn on (I think there's a proper term for this, but I can't remember it)?

-Matt

I believe the term you're looking for is "In Rush current". This is what you see when starting electric motors due to their induction. The current is much higher when starting than when running at steady state. Incandescent lights, however, are resistive devices, and therefore have no in rush current. Now wear and tear on the filaments from turning them on/off is another issue (heating/cooling). Fluorescent bulbs really get dinged by turning them on/off although there are 'soft start' ballasts available that help extend their life.

Aurbo99
01-17-2008, 06:02 PM
My power bill for the period of Dec 11 to Jan11:

45.88

Thats a whopping 6 bucks over my normal monthy bill.

2800 lights, 28 channels.

I fear my next seasons bill. 10,000+ Lights..

daviddth
01-17-2008, 08:38 PM
[quote=Matt]Incandescent lights, however, are resistive devices, and therefore have no in rush current.

Actually they do. As the filliment lights its resistence increases quite substantially, thus reducing the current. The difference in a Christmas light is nowhere near as much as it is in say a 100w or 150w globe, but the effect is still there - a higher initial starting current when cold, but as soon as the lamp warms, the current reduces.

This is the reason why 99% of ordinary globes blow when you turn them on rather than while they are running

rlilly
01-17-2008, 08:57 PM
[quote=Matt]Incandescent lights, however, are resistive devices, and therefore have no in rush current.

Actually they do. As the filliment lights its resistence increases quite substantially, thus reducing the current. The difference in a Christmas light is nowhere near as much as it is in say a 100w or 150w globe, but the effect is still there - a higher initial starting current when cold, but as soon as the lamp warms, the current reduces.

This is the reason why 99% of ordinary globes blow when you turn them on rather than while they are running

Agreed. Resistance increases with temperature. That's why superconductors are supercooled in order to function. However, my point is that the increase in intial current is nothing compared to that of induction motors.

omzig
01-17-2008, 10:29 PM
Incandescent lamps definitely have an in-rush current. A filament's resistance when it's cold is about 1/20 of what it is when it's hot. In fact in installations where a lot of large incandescent lamps are used, a "keep alive" circuit is often employed which maintains a very small amount of current to keep the filaments warm, although it's not enough to make them glow. There are "keep-alive" switches made for this purpose, that instead of completely opening the circuit they maintain a small current.

I had never really considered the in-rush current for mini lights because it's probably not that high. But now that I think of it, when you consider the many thousands of lights that are being used in our displays, I suppose it would add up pretty quickly especially if there is a lot of blinky flashy goin on.

I have yet to build my first controller and have yet to even look at Vixen (other than the docs), so I'm not sure of the particulars involved, but how dim is the lowest dim? Maybe on sequences where there is a lot of blinky flashy, very dim could be used for the off cycles to reduce in-rush. With these dimmable controllers, are the lights even visible when they are at the lowest dim value? Just a thought.

biffklg
01-18-2008, 09:37 AM
I just looked at my bill last night. I had about 16000 lights in 07 on olsens and in 06 I had about 5000 static. My bill went up about 30$ from 06 to 07 for the 2 months that my show spanned the bills. I also did not run my lights in 06 after Christmas, so $60 to run my show in 07, not bad.

Jeff Millard
01-22-2008, 06:57 PM
I'm a little slow jumping in here, but Dawn was nice enough to let me see the electric bills (she doesn't let me anywhere near anything having to do with money... a very smart girl I think) She compared the bills and says the entire display cost us $75 for the six weeks it was on. 28,000 minis, 100 C9's, 35 C9 strobes, 11 40watt blowmolds, 6 100watt spot lights, 3 motors, 2 indoor christmas trees and a bunch of lighted garland not included in the mini count.

Thank you oh great God of computer animated light control!!!

Jeff

daviddth
01-22-2008, 08:09 PM
[quote="daviddth"]However, my point is that the increase in intial current is nothing compared to that of induction motors.

Very true. Nothing like the feeling of starting a 9.15MW 11KV motor DOL (No soft starting at work!) We have 2 that size and a 9.09MW motor that gets started weekly... Makes our lights look awfully small lol

daviddth
01-22-2008, 08:13 PM
With these dimmable controllers, are the lights even visible when they are at the lowest dim value? Just a thought.

No. Here my 24V lights become visible JUST in the dark at about 35 to 40% depending on the lights. The 240V rope lights are about 28 to 32% and same for the silhouettes. Not tried the Par38 floods yet, but that will be the next test. Basically 40 to 100% is the range I'll use for dimming on most of my lights.

rlilly
01-22-2008, 11:22 PM
[QUOTE=rlilly;17932]

Very true. Nothing like the feeling of starting a 9.15MW 11KV motor DOL (No soft starting at work!) We have 2 that size and a 9.09MW motor that gets started weekly... Makes our lights look awfully small lol

Whoa! And I thought that 700 kW compressor that used to be mine was the monster!
Yes, the lights become a rounding error in comparison ....