Cost of Electric

[petena98]

Hi everyone

Will it cost less money to use 12v(with transformer)  50watts versus 220mains 50watts, if it does please can you tell me the cost comparison and if possible how do work it out.

Best regards

Peter

[Buenchico]

The power consumption of the appliance is given as 50W in both cases so, theoretically, you'll use the same amount of electricity in both cases. In practice, because transformers aren't perfectly efficient (i.e. energy is wasted when they heat up) it would cost slightly more to use a transformer.

If we assume that you're not using a transformer, you'll use 1 kilowatt-hour of electricity by using the appliance for 20 hours and 1 kilowatt-hour currently costs about 7p so, roughly, it will cost you about 8-and-a-half pence a day without the transformer and (because of those power losses) probably about 10p per day with it.

Chris

[landie]

Power (Watts) = Volts x Amps

so 50W = 12V x 4.166A

or 50W = 240V x 0.20833A

[petena98]

Hi

Thanks guys for the prompt replies

Best regards

Peter

[Tim B]

Just to chip in a little late.  Most transformers have an efficiency of around 98%.  So losses would be incurred, you'd lose 2% of your power, could you tell the difference?  The lamps won't demand 12V, they'll accept the 2% reduction and run on 11.76V.  Thus, by my reckoning, the cost will be the same.

Modern lighting transformers are a different animal, they chop the wave form and you end up with about around 10V, can you tell the difference in light output?

[Ray the DJ]

If you're using the power for light then you'll notice no difference.
However if you are heating water then the supply from a transformer would take longer to reach a required temperature and therefore cost slightly more.
It takes about 51 watts input to produce a 50 watt output from a transformer.