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Daryl in Nanoose 06-18-2006 09:59 AM

amps to watts
How do you calculate amps to watts?

Square Eye 06-18-2006 10:41 AM

Volts x amps = watts @ 100% efficiency.

You would need the length of the wire, the gauge of the wire and the co-efficient of the appliance you are powering to get real accuracy. The formula above is good for a ball park figure.

100 watt light bulb
120 volts

= .833 amps, in a perfect world.

inspectorD 06-18-2006 12:00 PM


Originally Posted by Daryl in Nanoose
How do you calculate amps to watts?

What are you up to?:D

To early for christmas lights.......;)

Daryl in Nanoose 06-20-2006 07:25 AM

Thanks guys, I am figureing out how big of a inverter to get and noticed some appliances have amps and no watts. Thanks again.

PaPaDan 06-30-2006 06:39 PM

Here is an Ohms Law chart for colculating volts and currents. If you know 2 factors in your cicuit you can use this
chart to find the additional information you need.

Example = You want to add 3 light fixtures to your shop,
each with 1 100 watt bulb and you know you have a 115 volt
service. You would devide 300 (P) by 115 (E) to find (I) which
would be 2.06. So now you know that your new circuit needs
to be capable of handling 2.06 amps.

Sauna 07-19-2006 08:30 AM

Easy now.. yeah no christmas light yet buddy!

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