Amp Rating
Ok - I thought I understood electricity ratings (watts, volts, amps). I know volts and undestand watts is a measure of work - but amps are a capacity. So when a motor has a rating of 12volts and...
Forum Discussion
Watts are not work, they're the rate work is done. Work is measured in joules, which are watt-seconds. But it's common to use watt-hours or kilowatt-hours instead.
One point of confusion is that people commonly say X uses so many amp-hours to refer to work/energy, but that's incomplete. Unstated is the voltage. It's used as a relative term.
Your 12 volt 12 amp motor, when running, uses 144 watts of power. If it runs for an hour, it uses 144 watt-hours of energy.
When working with batteries, it's common to just assume the voltage and only use amps and time. Then it's thought of as a 12 amp motor running for 1 hour using 12 amp-hours.
So, for your winch example - if the winch draws 12 amps for 10 minutes, it will consume 12 amps x 1/6 hour = 2 amp-hours.
One point of confusion is that people commonly say X uses so many amp-hours to refer to work/energy, but that's incomplete. Unstated is the voltage. It's used as a relative term.
Your 12 volt 12 amp motor, when running, uses 144 watts of power. If it runs for an hour, it uses 144 watt-hours of energy.
When working with batteries, it's common to just assume the voltage and only use amps and time. Then it's thought of as a 12 amp motor running for 1 hour using 12 amp-hours.
So, for your winch example - if the winch draws 12 amps for 10 minutes, it will consume 12 amps x 1/6 hour = 2 amp-hours.
