| Author | Topic |
|---|
Location:
Northwestern Sydney
Registered:
August 2002
|
|
power consumption of halogen lights
|
Tue, 13 January 2004 00:14
|
 |
Just a question ion power consumption of halogen lights compared to say a normal 60W globe, I read somwhere that somthing like 1 60W globe equates to approx 7 (or somthing) halogen globes.
Can any body confirm or denie this as I can't find the webpage I read this on.
I need to justify my wanting to use 20 or so low voltage lights in the garden to my missus 
|
|
|
Location:
Brisbane
Registered:
February 2003
|
|
|
Location:
Northwestern Sydney
Registered:
August 2002
|
|
Re: power consumption of halogen lights
|
Tue, 13 January 2004 00:31
|
|
The transformer I'm looking at is a 240V -> 12VAC 150W which will be powering between 5 and 7 20W Halogen globes
It's output is 12.5 Amps.
|
|
|
Location:
Brisbane
Registered:
February 2003
|
|
Re: power consumption of halogen lights
|
Tue, 13 January 2004 00:57
|
|
if you're using 7 x 20W (140W in total) halogens then they'll require 11.2A (@12VAC) to keep them lit.
one more bulb and you'll exceed capacity of transformer
there will be loss in the transformer hence the 10W headroom
i think someone with elec engineering background would know (with more precision) how much energy would be lost in the transformer
charles
|
|
|
Location:
Northwestern Sydney
Registered:
August 2002
|
|
Re: power consumption of halogen lights
|
Tue, 13 January 2004 01:01
|
|
What about bad earths? 
So one would be better to run the transformer at its rating
ie 5 x 20W + 1 X 50W halogens = 150 to get (maximum) light??
|
|
|
Location:
Brisbane
Registered:
February 2003
|
|
Re: power consumption of halogen lights
|
Tue, 13 January 2004 02:00
|
|
tis up to you - expect the transformer to run slightly warm if at 100% rated duty
but if it were my garden i'd run lots of low W bulbs - and use proper floodlights (240V quartz halogen) for floods. personally i don't like big, bright, direct lighting.
as for earths - dunno - ask Cool1 
|
|
|
Location:
Northwestern Sydney
Registered:
August 2002
|
|
Re: power consumption of halogen lights
|
Tue, 13 January 2004 03:15
|
|
That's my plan, to run low voltage lights basically to light up the driveway at night a luminate the path to the back door.
I'm not after daylight at night. And I'll have 2 240V flood lights on the pergola for Day/Night Backyard Cricket.
|
|
|
Location:
Canberra
Registered:
August 2003
|
|
Re: power consumption of halogen lights
|
Wed, 14 January 2004 04:24
|
|
A transformer will have no problem running at a light load, however if you exceed the wattage you draw too many amps and the coils melt and you start a fire and ruin your science project (not that this has ever happened to me or anything). Only drawin 140watts from a 150watt transformer will do no harm.
By law the output rating of the transformer should be after any internal losses. So you can draw 150w from that transformer without risking a fire. (there is normally an amount of tolerance to go above the rating, but that is pretty dangerous.)
|
|
|
I supported Toymods
Banned User
Location:
Brisbane
Registered:
May 2002
|
|
Re: power consumption of halogen lights
|
Wed, 14 January 2004 09:15
|
|
Being an AC supply it shouldnt get to warm operating at its full rated output.
How much are you looking at spending on the power supply? Dont limit your self to the power supplies that are marked for garden lights. Because there are other types that will allow use the amount of lights you are wanting to use.
|
|
|
Location:
Northwestern Sydney
Registered:
August 2002
|
|
Re: power consumption of halogen lights
|
Wed, 14 January 2004 21:55
|
|
I'm looking a Jaycar power packs of which I'll prolly need 3 or 4 to run the number of lights I'm planning to run. at about 70 bucks apiece.
You have another option there cool1?? 
|
|
|
I supported Toymods
Banned User
Location:
Brisbane
Registered:
May 2002
|
|
Re: power consumption of halogen lights
|
Thu, 15 January 2004 03:36
|
|
|
As long as you are keeping the supply inside you could/should just buy a big DC power supply. I have some 25Amp continuous switch mode power supply's which would do the job very well.
|
|
|
Location:
Northwestern Sydney
Registered:
August 2002
|
|
Re: power consumption of halogen lights
|
Thu, 15 January 2004 03:57
|
|
The supply will be outside but under cover and enclosed in a built in BBQ (next to bar fridge and Irrigation timer system)
Your starting to lose me on the power supply stuff:blush:
25Amps meaning that it can run more Lights that draw (insert halogen light current here) Amps
ie. light draws (say) 0.25 Amps / 25 amps = 100 lights??
Electronics is not a strong point of mine 
I cause bad earths.
what does a typical pond pump run off?? 240V or 12/24V
If what you're saing is applicable could I run a pond pump off the power supply as well as lights??
|
|
|
Location:
Brisbane
Registered:
February 2003
|
|
Re: power consumption of halogen lights
|
Thu, 15 January 2004 05:45
|
|
pond pumps are usually 240V AC powered.
keep pond pump separate to lighting power so it doesn't fry your lighting power supply when you accidently dig up the power line - plus mixing inductive loads (e.g. motors) and fixed load devices (incandescent bulbs) isn't a great thing. i don't mean a separately fused circuit, just not from the same power supply (if you are able to find a 12V pump)
as for your lighting power requirements, a 12V 20 Watt halogen requries about 1.7Amps to keep it lit. So a 25Amp switched-mode DC supply could keep 14 of them lit.
simple equation to work out DC current requirements: Watt = Volts * Amps
if you want to work out AC current requirements it gets a little more confusing.
|
|
|
Location:
Northwestern Sydney
Registered:
August 2002
|
|
Re: power consumption of halogen lights
|
Thu, 15 January 2004 05:53
|
|
Yeah that all sounds familiar I even recognise that formula, and that basically means I haven't yet killed off all my brain cells from school. So off to the pub.
What are the details of these 25Amp continuous switch mode power supply's Do Jaycar sell them (so I can see what you're talking about?
Pricing?
|
|
|
I supported Toymods
Banned User
Location:
Brisbane
Registered:
May 2002
|
|
Re: power consumption of halogen lights
|
Thu, 15 January 2004 11:58
|
|
Jaycar dont sell these. The ones I have are about $1200 new. I normally sell them for about $400 second hand.
But dont get me wrong, I'm not saying to buy one of mine. I'm just saying that there are other power supplies you can use for your lights.
|
|
|
Location:
Northwestern Sydney
Registered:
August 2002
|
|
Re: power consumption of halogen lights
|
Thu, 15 January 2004 23:19
|
|
I'm pretty much open to options. somthing to look into.
Ta Cool1
|
|
|
I supported Toymods
Banned User
Location:
Brisbane
Registered:
May 2002
|
|
Re: power consumption of halogen lights
|
Fri, 16 January 2004 06:43
|
|
|
No worries
|
|
|
