Chopping some power bills

Discussion in 'Electronics & Electrics' started by AgB deano, Nov 3, 2009.

  1. OP
    OP
    AgB deano

    AgB deano Member

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    I live in regional victoria :)

    Common inductive loads are heaters, lighting circuits, distribution transformers, arc welders and electric motors - many of which have some sort of power factor correction (in a PSU's case, the large capacitors that sit on the 240V line for passive or an Active PFC module). PFC is actually a rating of how efficiently the item in question is using power drawn from the mains (true / apparent, true being the amount of power being used by the device, apparent being the amount drawn from mains) and generally the reason it will screw with the jaycar meter is the means used to ensure that PFC (active or passive) is maintained. PFC is really important in EU countries because of the way customers are charged for power and arguably people that use UPS's :p. Not so much here though and every decent PSU out there has some sort of PFC, active or passive - otherwise the companies would not be allowed to sell the product in the EU.

    240V warning:: The best way to work out the amount of power an inductive load is drawing is to put a shunt on the line supplying the devices to work out the amount of current then P=VxI is your friend. Your average joe should never attempt this though, it is dangerous unless you have a clue what you're doing in which most people don't.

    A safer way to work out the load for lets say a fridge or my water pump out the back is guestimate the amount of time (i would love a power-mate to do it for me but that price is a little steep) the item in question is turned on, grab the power rating for that item and work it out.

    For instance I figure the water pump we use would be on for around 2 hours max a day (showers, washing loads, watering vegi patch an fruit trees, washing hands, topping up animal water bowls - the pump switches on with any water use), it is rated to 700W so over a period of 3 months it would use around (700x3x7x4x3) 117.6KW and would account for around $23.52 of the power bill.

    Fridges are different though, I worked out the main fridge in the house would be opened at least 20 times a day, i'd work out what the motor is rated at, listen to how long it stays on and work it out that way. Since it is a new'ish fridge with very good seals I think it would only turn on for those periods, fridges and freezers are quite good at keeping cool for long periods without the motor on. This is a real bit of guesswork though :)

    The water heater here is wired into the meter for offpeak tarriff's and only operates in offpeak hours. The only time it would switch on during the day is if the "boost" button on the meter is pressed, in which many arses get kicked. :D The hot water service itself is pretty efficient but it will possibly be replaced soon with the installation of a 2kW solar grid and a new hot water service.

    Our meter itself is not one of the old wheel meters, our meter is a newer digital meter that measures specific consumption during the hours of the day. The company we go with charges us different amounts for those different times, not just two standard rates (on peak, off peak) so we're already getting a good deal. So I guess all that is left is to cut the actual usage!

    There has been some very helpful suggestions in this thread, i'm pretty happy with the response actually. I'll try and keep the thread updated as I try different things but i'll definitely post next months bill :lol:
     
  2. BurningFeetMan

    BurningFeetMan Member

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    Hehe. I love the cold too, but some nights were pretty damn cold this year. :)

    Regarding light bulbs, I always select the lowest wattage classic bulbs, as modern lights give me headaches etc. I'm also a light turner-offer.
     
  3. Privatteer

    Privatteer Member

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    First off I would be checking the times you use most power. Despite how its billed the smart power option sometimes works out more expensive.

    Electric hot water? Change to gas or solar/gas boosted.
    If you do gas storage consider size of tank, do you really need to have 130+L heated all the time or is 85L sufficient. I halved my gas bill when my old one died and I replaced it with the 85L version.

    Energy efficient lights, minor effect but do as they die.

    If you want to get really serious, and have a alarm system get an output added that turns off most power circuits when its on.

    Chest freezer instead of upright.

    Decent insulation in roof. Less air con.

    Solar power system, rebates been slashed for the smaller systems but can be worth it.


    Proof it can be done 18 months ago I was using about 280$ in 60 days.
    About June I installed a 1600Kw solar system, but had bill down to about $180.
    [​IMG]
     
  4. Privatteer

    Privatteer Member

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    Those Jaycar meters are not true RMS last time I tested one so they read any switchmode power supplies ie computers about 20-30% lower that real draw.

    Ie my PC measured at 0.9amps but when measured with true-rms meter was really drawing 1.2amps.

    Edit: Newer power supplies with power factor correction will read a lot closer to real draw.
     
  5. OP
    OP
    AgB deano

    AgB deano Member

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    Nice work on the power savings :)

    I would hazard a guess that your psu does not have any form of PFC :) What sort of meter did you use to get the 1.2A reading? Clamp meter?

    We are hoping to see a good return for the 2kW solar system we want to install.

    As it stands, 60% of our usage is in the offpeak tarriff. A gas water heater is out of the question for us as we are regional vic and the nearest gas main is 20km away.

    We have a huge chest freezer, 550L fridge that is 4 stars, the 210L fridge that is 5 stars and a kelvinator clunker.. well yeah, it's an antique :)

    Half my problem is for example, I get home tonight and everybody is in bed yet I can count 11x 240v downlights, a television, hi-fi system, printer and computer that have been left on.. it is just frustrating at best. I am honestly starting to consider movement sensors with a 15 minute delay for all the lights in the house and setting the pc's to auto-standby after 30 mins and removing admin access. Bad habits FTW.
     
  6. Kyl3

    Kyl3 Member

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    Remembering to switch your lights off is a pretty decent step.. Small % but it's something you can do without having to think :)
     
  7. cavanor

    cavanor Member

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    to get an example of what a power hog uses. I use about $2.50 a day. 2 bedroom flat in Brisbane. TV on probably 6hrs a day, both computers on 24/7. Fridge on and dishwasher + washing machine used every 2nd day. Air con pumping.
     
  8. RobRoySyd

    RobRoySyd Member

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    Heaters are a very resistive load.
    As far as I know domestic consummers are billed for actual not apparent power.
     
  9. susmind

    susmind Member

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    My bill was $90/quarter living in studio flat with instant hot water & everything unplugged when not actively used.

    But power prices have just gone UP so I except next quarter to be $100-$110
     
  10. OP
    OP
    AgB deano

    AgB deano Member

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    Blonde moment there, I was thinking of air conditioners and typed heating for some reason :/

    We are billed for actual yes, my point was PFC is around because in the EU you're generally not. In the EU PSU's must have some sort of PFC, PSU companies would be stupid to create an expensive psu that a solid chunk of consumers wouldn't be able to buy, hence we receive PSU's with PFC as a norm.

    Still waiting on this mains meter for an update! :)
     
  11. MagyaR

    MagyaR Member

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    WTF? these Jaycar wireless plugs are shit, I've had 4 fail on me, unless it doesn't like 2 power boards connected to it BUT only the pc is on and the tv and that is way under 10amps and 2400w, what a crock of shit.
     
  12. mareke

    mareke Member

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    They are badly designed. Read the posts towards the end of the thread below and you'll see that others have found the same thing.

    http://forums.overclockers.com.au/showthread.php?t=644900
     
  13. Pugs

    Pugs Member

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  14. mareke

    mareke Member

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  15. Pugs

    Pugs Member

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  16. mareke

    mareke Member

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    Well I guess if you want to know the amount of greenhouse gas you produce then by all means pay an extra $230 and get the Clipsal.
     
  17. LethalCorpse

    LethalCorpse Member

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    My electricity provider prints the greenhouse gases used to produce my electricity on my bill, I'd guess yours might do the same. It's a simple multiplication.
     
  18. dmandn

    dmandn Member

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    Sorry for the thread hack, apart from my question, the rest of Onyx's post was very good, I completely agree with it.

    We have one of those edwards solar hot water systems (I think its edwards, was main competitior to solarheart and now owned by solarheart anyway), once the sun goes down, if the booster is off by around 11pm the water is freezing :(, its a bew house but we get told when we complain there is nothing wrong with the unit, what do you guys think?
     
  19. Jonchilds

    Jonchilds Member

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    Check to see if you have a water leak somewhere (check meter while all taps are off), or if you're using lots of hot water.

    The other thing that happens with cheap-o SHWS is they don't have a reverse flow valve which means they can lose heat if it cools down a lot outside and there's no sun. Not a problem if you're not using the electric heater tho.
     
  20. Daemonic

    Daemonic Member

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    Here is another Jaycar power meter, measures your total usage.

    Mains power meter
     

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