Is 60 watts at 12 volts the same as 60 watts at 240 volts?

st999

I know it was inefficient but I used to use a 60 watt 240 volt filament bulb as a heat source.
If I was to use a 12 volt battery charger and a 60 watt car bulb would I need 20 60 watt bulbs, to produce the same amount of heat?

Gerry1

60 watts is 60 watts regardless, even if it's a gas flame or a candle.  You might get the odd extra watt from the heat emitted by the charger, but it wouldn't be a free lunch, you'd be drawing that much extra from the mains.

unforeseen

Using a 60W 240v is more efficient as all the input gets turned into heat by the bulb. 
Using 12V 60W means that not only are you using 60W for the bulb but you now also get losses in the charger. Transformers are not 100% efficient so more input is needed to produce 60W output. 

Hasbeen

st999 said:

I know it was inefficient but I used to use a 60 watt 240 volt filament bulb as a heat source.
If I was to use a 12 volt battery charger and a 60 watt car bulb would I need 20 60 watt bulbs, to produce the same amount of heat?

LOL do not know. Is that 100 amps per hour? 12v charger?

st999

If 60 watts is 60 watts would I be using the same amount of electricity, disregarding what the charger used?

Gerry1

Yes.  The 12V bulb would draw a higher current but Volts x Amps = Watts.

Talldave

You'd need wires capable of handling 5 amps.

matelodave

60 watts at 12 votls will draw 5amps and 60watts at 240 volts will draw 0.25amps but they still use the same amount of power = 60watts. So having it on will use 60watt/hours of energy 
Although, as others have said, most battery chargers will only be around 90-95% efficient and as batteries aren't 100% efficient either (you need to put in about 10% more than you get out due to the conversion of electrical energy into chemical energy and then back again, as well as generating some heat in the process) then you will probably use around 70watts, so it will cost you more

st999

Talldave said:

You'd need wires capable of handling 5 amps.

There's loads of them in cars.

Cardew

As the others have stated an output of 60 watts is 60 watts regardless of the voltage used to produce that output; the variable is the amperage.

If your intent is to power the 12 volt 60 watt bulb from a battery charger and use it purely as a heat source, again as said above, there will be losses in the battery charger. However a guy named Albert Einstein has some good news for you.

Many years ago, but still true today, Einstein  proved that you cannot destroy energy and it can only be changed from one form to another. In the case of the battery charger the losses of electrical energy in that charger will be changed to heat, and provided the heat from that charger is utilised, you will suffer no losses from your unique set up!

However as you will need mains volage to power your battery charger ------!