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Battery Depletion
ELE 100
Craig Baron, Drew Somers, Rebecca White
Lab completed 10/13/04
Report due 10/25/04
Abstract
Batteries drain quickly at first, then steadily for a relatively long period of time,
and drop off quickly to at the end. They can output a useful amount of power for about
2/3 of this time. In this lab we measured and analyzed the depletion of a battery using a .5
ohm resistor at 30 second intervals for about 35 minutes. Our particular battery had a
useful life of 19 minutes, and an overall life of about 30 minutes. How much useful
energy and average power over the useful period?
Good title page
Introduction
The purpose of this lab was to gain an understanding of the energy and power
obtained from a AAA battery, and how they change or deplete as the battery is used. We
measured the voltage of our system at 30 second intervals, and using the resistance
V
V2
(known) calculated the current ( I  ), power ( P 
) and cumulative energy
R
R
(  Pt ). Objectives?
Experimental Setup
Equipment used
0.5 ohm resistor
1 AAA  1.39 volt battery
2 wires with alligator clips
Voltmeter
Stop watch
Photo is good. A schematic diagram would be
helpful.
Procedure
Test to see if the battery has enough
power to effectively do this lab this is
purpose: it should have close to 1.5 volts. Power is measured in watts. NiMH batteries
have an open circuit voltage of about 1.35 volts. Take the 1.5 AAA battery and connect
the positive and negative terminals to opposite ends of the 0.5 ohm resistor. Connect the
voltmeter to both sides of the resistor. Use the stop watch to record the voltage every
thirty seconds until the voltage drops off rapidly. Calculation of power and energy?
Results
See attached data spreadsheet. Results are more than the data. They should be
summarized in words. Graphs should accompany the results so they can be seen in the
context of the words.
Discussion of Results
The battery had lost about 1466.2 Joules (4 significant figures is sufficient, 1466)
of energy at 19 minutes. The power level started out high then began to drop a little and
started to level out at a slow decline. Around 19 minutes, the power began to drop off
quickly leaving the battery with an insufficient amount of power to do what?. With 0.5
ohm resistance, our battery’s useful life was about 19 minutes with the power level being
 1.125 Watts. Good but these are measured Results.
There is a noticeable error in the data around 10 minutes; we had touched the
resistor to see if it was warm, and that caused a small jump in the power level. Good.
Data should be incorporated into the report, not a separate document.