# lot lighting costs to operate/kw/hr?



## rlc3854 (Dec 30, 2007)

As an apprentrice let us know what your teacher says is the answer. As a project manager let us know if you were able to up sale a system to correct their problem.


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## lmwolfwalker (Aug 25, 2009)

*Answer...*

As an approximation for the owner of the mobile park I used the following: 


3amp startup
1.2 operating
400watt Metal Halide lamp
120volts
1000/watts = length of time to use 1000watts in hours
 hours of operation/ length of time=kwh 

Finally, multiply kilowatt-hours by the cost per: 
kWh * (cost per kWh) = cost to operate

Summer operation approximately 9.5hrs.
400 x 9.5=3800/1000=3.8x.06=.23
$0.23 per day
$6.84 per month
Winter operation approximately 15hrs.
400x15=6000/1000=6x.06=.36
$0.36 per day
$10.80 per month
$113.76 per light pole per year


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## 480sparky (Sep 20, 2007)

lmwolfwalker said:


> ..........watts / 1000 = kW .......


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## lmwolfwalker (Aug 25, 2009)

am I wrong on this???


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## 480sparky (Sep 20, 2007)

Watts *** 1000 = kw.

Watts */ *1000 = mw.


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## lmwolfwalker (Aug 25, 2009)

480sparky-

thanks. goes to show you to look closer at your math....and to think I use to teach math...thanks again.


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## lmwolfwalker (Aug 25, 2009)

okay, so let me think about this....if a 1000w lamp consumes 1kwh in exactly one hour...correct? So, then a 400w will consume 1kwh in 2.5 hours...correct? So...1000/400=2.5 hours to consume 1 kwh.....if operation of lamp is 15hrs/2.5 hours for 1kwh=6kwh x .06=.36cents.....

comments please


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## 480sparky (Sep 20, 2007)

You have a ballast between the lamp and the source, so your lamp wattage is not what you base your calculations on.


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## lmwolfwalker (Aug 25, 2009)

Ah, yes. Got it figured now. Thank you for your help.


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## Lighting Retro (Aug 1, 2009)

480sparky said:


> You have a ballast between the lamp and the source, so your lamp wattage is not what you base your calculations on.


Yes, your standard 400W MH actually uses somewhere between 455 and 460 Watts with ballast. 1000W MH is around 1080-1100. Be sure to calculate that in as well. :thumbsup:


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