December 2021 - 68

TOOL BRIEFING
concern of using such a stressful load on
a battery is damage to the battery and the
potential for injury if the battery were to
fail under such a heavy load.
Follow the load tester manufacturer's
instruction to limit the potential for damage
or injury when operating.
REFRACTOMETER
(SPECIFIC GRAVITY) TESTING
While many newer batteries are not serviceable,
technicians in the industry will
still encounter batteries that have removable
service caps. This option allows technicians
to sample individual cell acid and
assess the density for diagnostic benefit.
To begin the process, the refractometer
must be calibrated with a few drops of distilled
water being placed on the clean sample
plate. Once the hinge plate (also called
a " daylight plate " ) is closed, the technician
needs to point the sample plate towards a
sufficient light source and view the measured
value on the display. If the display
indicates the sampled water has zero acidic
value (32-degree freeze point), wipe the
plate clean and begin sampling individual
cells in a similar manner. If the distilled
water doesn't show zero acidic value, the
refractometer must be calibrated to zero
to progress (typically done with a small,
flathead screwdriver provided by the
refractometer manufacturer).
Fortunately for us, most vehicle battery
specific refractometers provide
text indicating " good " , " fair " , or " needs
recharged " based on calibrated values.
Result of this type of test may vary with
calibration or sampling errors.
CASE STUDY: 2001 FORD
FOCUS WAGON
This vehicle came in with an immediate
no crank, no start concern. I popped the
hood and verified battery terminal to post
connection, measured live voltage values,
and assessed the battery's condition using
a refractometer and load tester to document
multiple methods of diagnosing battery
condition.
Upon initial inspection, I found severe
corrosion on the negative battery postto-terminal
connection due to sulfation.
I also measured an unsurprisingly
lower than normal battery voltage with a
DMM at ~12.2V. In wanting to capture a
diverse array of methods for verification,
I decided to use a refractometer (as the
battery was serviceable) and a load tester
to demonstrate the benefit of both tools
in service. When sampling the specific
gravity of the battery cells, I found the
specific gravity (density of battery acid
in cells) to average ~1.19, which indicated
low density (also indicated by initial
DMM reading).
The final step was to utilize the load
tester. The battery was rated at 525
CCA's, but when I applied the higher
amperage load test, the battery yielded
300 CCA's, further verifying results of
the DMM and refractometer.
I replaced the battery and the vehicle's
operation returned to normal.
DSO DIAGNOSTICS
As the industry continues to use advanced
methods of testing, my personal preference
for assessing a battery's condition is
the Pico Diagnostics Battery Test. This
test centralizes the most comprehensive
data, projects dynamically physical values
of voltage and current, and creates a
file that can be saved, printed, shared, and
displayed for reference and illustration.
CASE STUDY: 2017 FORD F-150
This vehicle came in with a complaint of
remote start intermittently inoperable
after a long sit time.
The truck was purchased in 2021 with
less than 20,000 miles on it from a local
dealer (it sat for many months after the
original owner purchased it). In wanting
to gain familiarity with some embedded
digital storage oscilloscope (DSO) battery
test software, I decided to use this vehicle
as a way to document the features of this
tool for class use. To begin this test, I connected
the DSO to a laptop, opened the
software, filled in ambient temperature
and battery specifications, connected
the test leads as specified (voltage probes
on battery connection points and 2000A
68 PTEN DECEMBER 2021 www.VehicleServicePros.com
probe around the starter M cable on channel
2), selected start on the software, then
cranked the engine and gathered data/
interpreted the results.
Findings from this test indicated my
initial suspicion: the battery needs to be
recharged and cycled normally. The battery
output 1080 CCA's, though rated at
880 CCA's. Initial voltage while testing
was 12.3V (40 percent SOC) but dropped
to 9.07V when cranking, which is well
below the industry recognized standard
of 9.6V when cranking.
After cycling the battery and running
a second test, I found the battery's output
to peak at 1026 CCA's, though resting
voltage was raised to 12.6V (80 percent
SOC). The software indicated the battery
performed sufficiently and no longer
needed a recharge for assessment.
Of the methods discussed and displayed
above, I must state that two major
tools used to assess a battery's static and
dynamic conditions have more potential
in the field: digital multimeters and
DSO's. Both should be considered prioritized
tools for technician ownership as
they have the potential for use in many
other mechanical and/electrical diagnostic
routines.
I must note that while battery analysis
may be prioritized by technicians when
dealing with a slow crank, no crank, and/
or limited accessory operation, a faulty
battery can cause more severe symptoms
and should not be overlooked when completing
diagnostics for more difficult
issues on any vehicle.
CHRIS REYNOLDS is an
ASE Master Technician,
ASE-Education Foundation
evaluation team leader,
and an associate professor
of automotive technology at Lewis & Clark
Community College in Godfrey, Illinois. He is
currently in his second year of study towards
a doctor of education in educational practice
at the University of Missouri St. Louis. He
enjoys time with his wife and three children,
and advocating for the needs of the
automotive service industry and the field of
technical education.
http://www.VehicleServicePros.com
December 2021

Table of Contents for the Digital Edition of December 2021
