4
TBP 100
EN
BATTERY TEMPERATURE
+20˚F
0˚F
-20˚F
DECREASE BATTERY RATING BY:
1 STEP
2 STEP
3 STEP
OPEN CIRCUIT
VOLTS*
PERCENT OF
CHARGE
11.7 Volts or lower
0
12.0
25
12.2
50
12.4
75
12.6 or higher
100
TEMPERATURE COMPENSATION 1 STEP = 50 CRANKING AMPS.
TESTING THE CHARGING SYSTEM
1.
Connect the tester the same as for battery testing.
2.
Start the engine and allow it to reach normal operating temperature.
3.
Run engine at 1200 to 1500rpm. CAUTION: Stay clear of moving engine parts. Do not press
the load switch.
4.
Read the meter. A reading in the red band area indicates a problem in the charging system
that will undercharge a battery; if the meter is beyond the OK area, the charging system is likely to
overcharge the battery.
STARTER MOTOR TEST (12VOLT VEHICLES)
This test identifies excessive starter current draw, which makes starting difficult and shortens bat
-
tery life. Perform battery load test-proceed to make sure if battery is GOOD.
ENGINE MUST BE AT NORMAL OPERATING TEMPERATURE
1.
Connect negative (black) clamp to the negative (NEG, N, -) battery post. Connect positive
(red) clamp to the positive (POS, P, +) battery post. ROCK clamps back and forth to ensure a good
electrical connection.
2.
Disable the system ignition so the car will not start.
3.
Crank the engine and note the voltage reading during cranking.
4.
A meter reading of 9 volts or less indicates excessive current draw. This may be due to bad
connections or a failing starter motor; or the battery is too small for the vehicle’s requirements
If the load indicates poor battery condition, allow the
battery to stabilize for a few minutes and check the open
circuit voltage by voltmeter. This is a good measure of
the percent charge in the battery. The battery is consi
-
dered charged if it measures 75% or more. If it failed
the load test with 75% charge, it should be replaced. If
the battery charge measures less than 75%, it should be
charged and load tested again. Replace the battery if it
fails again. The values in the following charge are for a
12 volt battery; divide these in half for 6 volt batteries.
