[General] How To convert known Wattage to Amps and known Amps to Wattage.

[Nut Kracker]

Just thought I would explain how to convert known Wattage to Amps and known Amps to Wattage.

This is very handy when you know the Wattage of a component and need to know the Amperage for the correct fuse or wiring to use,
or you know the Amperage, and need to know the Wattage.

It's very simple and here are the equations.


To work out the amperage.........
Watts (divided by) Volts = Amperage.
Example - 120 watts (divided by) 12 Volts = 10 Amps.

To work out Watts........
Amperage x Volts = Watts.
Example - 10 Amps x 12 Volts = 120 Watts.


Just remember that just because a component/s is drawing say 60 watts, don't just use a 5 amp fuse.
This will be right on the limit of the power consumption and will not allow for small current spikes or slight over loads in the system.
If you use a too higher amp fuse, it will take longer to blow if there is a problem and could cause serious damage to the component and or the electrical system.

Do not use foil or any other things to relace a fuse as these foriegn objects will not blow as a fuse is designed to.

 

[K-BAGZ]

Ohm's Law is also very handy and basic auto electrical knowledge.

 

[Nut Kracker]

This may be handy.
The Ohm's Law Calculator.
Ohm's Law Calculator

 

[Jxfwsf]

And just to make it look pretty here are the formula's in a triangle, makes it easy to remember what to multiply or divide..... if you can memorise them....

ohms law -->

<--power


P = power/watts
V = Voltage (Could use "E"lectromotive force, but "V"olts is easier to remember for most people)
R = Resistance
I = Amperage

Ohms law:
V/I=R
V/R=I
R*I=V

Power calc
P/I=V
P/V=I
V*I=P

 

[VR38]

my head hurts...

 

[Nut Kracker]

my head hurts...

Mine too...:bomb:
I think the first post is the easiest to remember for the layman.

 

[Immortality]

Then all you need to do is work out the required wire cross section taking into account the length of the cable to minimise voltage drop.......

 

[begrubb]

Then all you need to do is work out the required wire cross section taking into account the length of the cable to minimise voltage drop.......

then consult: AS/NZS 3000 2007, AS/NZS 3008 2009

 

[Immortality]

Yeah, I got one of those somewhere around here