Midtronics MDX-300 Series, Instruction Manual, Page: 11 / 21

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MDX-300 Series
Test Messages
In some cases the tester asks for additional information before completing
a test. It may also warn you of a condition that prevents proper testing.
Test Message Interpretation
BATTERY TEMP.
ABOVE or BELOW
0° C
If the tester detects that the temperature of the
battery may make a difference in the result, it
will ask you to select if the battery temperature is
above or below 0 ˚C. It will resume the test after
you make your selection.
BEFORE or
AFTER CHARGE
For a more decisive result, the tester may ask if
you are testing the battery before or after charging.
If the vehicle has just been driven, select BEFORE
CHARGE. It will resume the test after you make
your selection.
continued
Decision Interpretation
CHARGING
VOLTAGE HIGH
(continued)
The regulator controls voltage output based on
the battery voltage, under-hood temperature, and
vehicle loads used. In other words, it controls the
maximum voltage the system can produce based
on the current needs and amount of current that
can be produced by the spinning of the rotor in
the alternator. The normal high limit of a typical
automotive regulator is 15.0 volts +/–0.5. Refer
to the manufacturer specifications for the correct
limit, which may vary by vehicle type.
A high charging rate will overcharge the battery
and may decrease its life and cause it to fail. If the
battery test decision is REPLACE and the charging
system test shows CHARGING VOLTAGE HIGH,
check the battery’s electrolyte levels. A symptom of
overcharging is battery fluid spewing through the
vent caps, which causes low electrolyte levels and
harms the battery.