Life of a Battery
The users guide of my scientific calculator says its battery life is “approximately 9000 hours continuous display of flashing cursor OR approximately three years when left with power turned off.” I use the calculator on an average of 30 minutes daily. Approximately how long will the battery last?
Labels: mathemagic
posted by ToM at
8:53 PM
11 Comments:
Each day the calculator consumes 1/18000 of available usage time plus 23.5/24 x 1/(3 x 365)of idle time.
I make it about 1053.5 days, i.e. short of three years by (again) FORTY TWO days!
Good morning all.
Let x be the energy consumption per our when the calculator is on and y when the calculator is off. If E is the total energy of the battery, we have x=E/9000 and y=E/(3*365.25*24).
The amount of energy the calc spends every day is D=0.5x+23.5y, and so the duration of the battery in days is E/D=1/(0.5/9000+23.5/3*365.25*24)=1053.56 days = 2,88 years
Everyone is making the assumption that when the cursor is just blinking is the same as making calculations. Entering data and making calculations takes a little more energy then just a blinking cursor, therefore it is impossible to determine exactly how long it would last. (unless he just stares at a blinking cursor for 30 minutes everyday).
I assumed Chris uses the calculator just to see the cursor blinking... ;)
This post has been removed by the author.
... true ;)
kick
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This post has been removed by the author.
I'm sorry for all the deleted post. I've been having tremendous problems getting my posts through.
buying the claculator was a mistake.
should've bought solar powered instead. :P
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