BESA-12P User’s manual
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37 -
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Page 23
To understand the working principle of the tests,
let‟s look at the wave form
displays taken during the cranking tests with an oscilloscope.
Figure (A) above shows the voltage profile of a healthy battery during the
cranking of an engine. The graph starts off at the battery's nominal voltage,
and a voltage drop is detected when the vehicle is cranked. The voltage
recovers to the battery's nominal voltage and eventually rises to
approximately 14.4 V when the alternator starts charging the battery.
For Figure (B) where a typical 2 year-old battery, you noticed the difference
in the voltage drop which indicates that it is weaker but still usable.
Whereas Figure (C) represents a very weak battery that can barely crank a
car and is due to fail in the very near future.
As voltage profiles can indicate the relative ability of the tested battery in
starting an engine, so there is no need for knowledge on the starter motor
requirement or the battery's rating and size.
BESA12P will capture the highest voltage drop and calculate the final
results which should not be lower than 9.6V average during cranking and
computes the result after the test.
10.1
– Begin Testing
1. With engine OFF, place
the vehicle transmission in NEUTRAL for Manual
and PARK for Automatic then apply the parking brake.
2. Connect the analyser to the battery terminals and the display will light up as
shown (Fig 52).
Figure 52
BESA-12
BATTERY ELECTRICAL
SYSTEM ANALYSER
