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Solid States Devices => solid state devices => Topic started by: magnetman12003 on August 17, 2016, 09:01:52 PM

Title: NEED BATTERY ADVICE
Post by: magnetman12003 on August 17, 2016, 09:01:52 PM
I have a small 12 volt fan rated at .30 amps.

If I used a fully charged 12 volt 12 amp hour battery how long will I be able to run the fan?
Same question for a 7 amp hour battery and a 1.2 amp hour battery.
Is there some sort of formula for figuring this out?
Title: Re: NEED BATTERY ADVICE
Post by: Magluvin on August 17, 2016, 11:12:13 PM
Quote from: magnetman12003 on August 17, 2016, 09:01:52 PM
I have a small 12 volt fan rated at .30 amps.

If I used a fully charged 12 volt 12 amp hour battery how long will I be able to run the fan?
Same question for a 7 amp hour battery and a 1.2 amp hour battery.
Is there some sort of formula for figuring this out?

Basically it works like this...

12ah will cover either 12 amps for 1 hour or 1 amp for 12 hours.  So 1ah can run .3 amps for just about 3.3 hours. And 12ah can run .3amps for nearly 39.6 hours hours.   

12ah - 12amps for  1 hour
12ah - 1amp     for 12 hours
12ah - .3amps  for 39.6 hours

7ah - .3amps    for 23.1 hours

1.2ah - .3amps  for 3.96 hours

Over the range of hours the voltage will decline from full charge down to the final count down. So say the battery is 13.2v to start(new battery settled resting voltage after full charge) and can be down to around 12v to 12.3v at the finish line, depending on the battery quality and or condition.

Mags