I am currently working on a project at work. We need to light 75 acres for security reasons. I have chosen 42 1500 watt metal halide lights to do the job. It has come down to the annual cost to run the lights before the main office will make the purchase. I need some formulas for calculating kwh use. I will be running 277 volt, and I have figured the amp draw to 6 amps each. I know the local kwh price from our utility bill for the terminal. I know I have the formulas somewhere in my organized shop/office, but am running out of time.
Outdoor Lighting- annual cost to use
- Thread starter gasmanva
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bphgravity
Senior Member
- Location
- Florida
Re: Outdoor Lighting- annual cost to use
The basic formula for calculating power costs is:
$ = Watts x Hours Used Per Day x Rate Per Hour / 1000 x Total Billing Cycle Days.
The basic formula for calculating power costs is:
$ = Watts x Hours Used Per Day x Rate Per Hour / 1000 x Total Billing Cycle Days.
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
Re: Outdoor Lighting- annual cost to use
As long as you want something fast to use with your rough numbers. It would be far better to use the input watts for each fixture instead of using the amps.
Volts times Amps/1000 = KVA
KVA times Efficiency times Power Factor = KW
KW times hours on = KWHR
KWHR times billing rate = $
edited forgot factor of 1000
[ September 21, 2004, 08:31 AM: Message edited by: jim dungar ]
As long as you want something fast to use with your rough numbers. It would be far better to use the input watts for each fixture instead of using the amps.
Volts times Amps/1000 = KVA
KVA times Efficiency times Power Factor = KW
KW times hours on = KWHR
KWHR times billing rate = $
edited forgot factor of 1000
[ September 21, 2004, 08:31 AM: Message edited by: jim dungar ]
Re: Outdoor Lighting- annual cost to use
For a very rough estimate, and assuming $.10 per KWH, lights on for 12 hours per night, then it would cost $1.8 for each 1500W per day.
If we round that up for PF, maybe $2 per day. So you are roughly talking $85 bucks a day for your 42 lights.
Steve
For a very rough estimate, and assuming $.10 per KWH, lights on for 12 hours per night, then it would cost $1.8 for each 1500W per day.
If we round that up for PF, maybe $2 per day. So you are roughly talking $85 bucks a day for your 42 lights.
Steve
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