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 12 amps are the amps consumped of amps over an hour (60 minutes)? or is that a constant draw of amps per minute?If it were watts (it would be volts x amps = watts or in this case 144 watts) - but again, watts are a measure of work - not a capacity or a rating of wires.This all goes back to me using a 12 volt winch with a 12 amp rating - so if i'm sizing a battery and I expect the motor to run for no more than 10 minutes then i'd use 2 amps if amps are measured per hour.What am I missing?Forgive my ignorance, but it's better to ask and understand it than spend money foolishly.Thanks in advanceJosh

I think you are confusing Amp Hour with Amp. Amp Hour is a metric used in storage for how many amps (flow) can be drawn from a battery bank over a course of time before discharged. Amp by it self is current (flow in the common analogy)On google: Voltage is measured in volts, current is measured in amps and resistance is measured in ohms. A neat analogy to help understand these terms is a system of plumbing pipes. The voltage is equivalent to the water pressure, the current is equivalent to the flow rate, and the resistance is like the pipe size.What are amps, watts, volts and ohms? | HowStuffWorksscience.howstuffworks.com/environmental/energy/question501.htm

Amps: Amperes, commonly known as amps, measure the flow of electricity as an electric current. Specifically, it measures the amount of electrons that flow past a certain point per second.PER SECONDAmp Hour Rating..that is how batteries are ratedif a battery has a rating of 100AH @ 20 Hr rate, then that battery was discharged over 20 hours with a 5 amp load.12V winch with a 12A rating will use 12 amps per second to run motor at rated speed.

think of amps as rate of flowlike 1 quart per minute verus 1 gal per minute of water12 amps is a current/flow rate being used, if that motor runs for 1 hr, you use 12 ampHrs at 12v or 144 watt hrswater at 1 quart per minutes needs 4 minutes to fill a gallon bucketwhile 1 gal a minute will fill the same bucket in 1 minute10 minutes water run a 1qt per minute is 10qts aka 2.5 gallons of wateryou have a 12amp motor, buy a 15amp switch or even a 20 amp switchyou want the switch contacts to have a higher rating than the max draw of the motor, so the contacts do NOT heat up and burn up or get pitted

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.

Amp Rating | Good Sam Community

wa8yxm
Explorer III
Sep 01, 2017
You are confusing Amps and Amp Hours

Amps is a rate of flow.. Gallons per minute

Amp hours are Amps times Hours Gallons delivered

I will use "Gallon minutes" for this

If you are flowing 5 GPM you can fill a 5 gallon bucket in 1 minue

The rate is 5 and the use is too.

But let's say you had a variable faucet

IT runs 3-15 Gallon, and you start at oh, say 15 (Quickly filling the bucket) then as it fills you "Throttle" back to 3 GPM till full

Your rate (Amps) is all over the range of 3-15 BUt your AMP HOURS is still 5
jodeb720
Explorer
Sep 01, 2017
So my expectation is I could get a 12 amp hour battery (12 Volts) and I could use the winch to pull a motorcycle up a ramp onto the back o my 5er and using the winch (not at maximum load) I'd use about 2 amps of the battery capacity.

Once the bike is in place, i'd recharge the batter to full capacity.

So - 12 Ah battery would suffice for this?

As we get older, things seem to get heavier and we look to use leverage to make things easier.

In this case, I'm looking for those wild electrons to help me out.

And by the way, thank all of you for the help in getting this sorted out. I really appreciate the clarity.

Josh
MrWizard
Moderator
Sep 01, 2017
Yes as stated you would use 2 amp hours of the battery capacity

Only one battery?
Then because of perkut effect you would use a little more than that

That's the chemical reaction verus time thing
Where a battery rated at 100 amp hrs , only if you use less than a 5 amp load
Use more the capacity goes down

Means you could use 5 amps for approximately 20 hours to reach total discharge , which is bad

But if you use 12 amps you can not do that for 8.5 hours, instead it might last 7 hours or maybe less

But in your case of only ten minutes, the effect on total capacity in minimal

Just like driving your vehicle
Pick a flat road do 50 mph get better mileage, than going up hill at 60 MPH
2oldman
Explorer II
Sep 01, 2017
..
mike-s
Explorer
Sep 01, 2017
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.
MrWizard
Moderator
Sep 01, 2017
think of amps as rate of flow
like 1 quart per minute verus 1 gal per minute of water

12 amps is a current/flow rate being used, if that motor runs for 1 hr, you use 12 ampHrs at 12v or 144 watt hrs

water at 1 quart per minutes needs 4 minutes to fill a gallon bucket
while 1 gal a minute will fill the same bucket in 1 minute

10 minutes water run a 1qt per minute is 10qts aka 2.5 gallons of water

you have a 12amp motor, buy a 15amp switch or even a 20 amp switch
you want the switch contacts to have a higher rating than the max draw of the motor, so the contacts do NOT heat up and burn up or get pitted
Old-Biscuit
Explorer III
Sep 01, 2017
Amps: Amperes, commonly known as amps, measure the flow of electricity as an electric current. Specifically, it measures the amount of electrons that flow past a certain point per second.

PER SECOND

Amp Hour Rating..that is how batteries are rated
if a battery has a rating of 100AH @ 20 Hr rate, then that battery was discharged over 20 hours with a 5 amp load.

12V winch with a 12A rating will use 12 amps per second to run motor at rated speed.
mrkoje
Explorer
Sep 01, 2017
I think you are confusing Amp Hour with Amp. Amp Hour is a metric used in storage for how many amps (flow) can be drawn from a battery bank over a course of time before discharged. Amp by it self is current (flow in the common analogy)

On google:

Voltage is measured in volts, current is measured in amps and resistance is measured in ohms. A neat analogy to help understand these terms is a system of plumbing pipes. The voltage is equivalent to the water pressure, the current is equivalent to the flow rate, and the resistance is like the pipe size.
What are amps, watts, volts and ohms? | HowStuffWorks
science.howstuffworks.com/environmental/energy/question501.htm

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