Electrical/Electronic Systems
Work Example 9

WorkKey Level: 4
NATEF Automotive Tasks: VI.B.1

You must determine if a battery should be replaced.  You take a specific gravity reading of each cell.  The readings are as follows:

Cell	Reading
1	1.145
2	1.182
3	1.131
4	1.131
5	1.158
6	1.173

Your service manual states that a battery must be replaced if there is a range of 0.050 (50 points) in the specific gravity readings of the cell.

a.  What is the lowest specific gravity reading of the cells?

b.  What is the highest specific gravity reading of the cells?

c.  What is the range of the specific gravity readings of the cells?

d.  Should you replace the battery?

e.  How can you explain the need for a new battery to a customer?

Solution: 

a.  Reading from the chart, cells 3 and 4 have the lowest reading of 1.131

b.  Reading from the chart, cell 2has the highest reading of 1.182

c.  The range of specific gravity readings is 0.051
(highest - lowest) = (1.182 - 1.131) = 0.051

d.  Yes

e.  Answers will vary