Berkeley CSUA MOTD:Entry 38746
Berkeley CSUA MOTD
2017/10/16 [General] UID:1000 Activity:popular

2005/7/21-22 [Science/Electric] UID:38746 Activity:moderate
7/20    I have a 12V fan that takes 10W. If I power it using a 2000mA
        battery, how long does it take? Basically I don't have a good
        clue on the relationship between wattage, amp, and voltage. Thanks!
        \_ V = IR and P = VI. Didn't you take physics?
        \_ You probably have a 2000mAh battery.  That's 2000 milli-amp hours.
           Given that, you should be able to figure out how long the
           battery ought to last.
           \_ 144 minutes.  -nop
              \_ It's impossible to answer this question without knowing the
                 voltage of the battery.
              \_ Assuming that it's a 12V battery.
              \_ Really?  I get 25: --dbushong
                 \_ Dave, your answer seems to have the units of
                    25/minute.  Check your units.  I agree with nop.--PM
                    \_ Pfft.  Units.  --dbushong
                 \_ 144 minutes ... P = VI, 10W = 12V * I, I = .8333 amps.
                    2 Amp-hours @ .8333 amps will therefore take 2.4 hours
                    to run out making 144 minutes.
2017/10/16 [General] UID:1000 Activity:popular

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