Load Test - Jeep 1997 Grand Cherokee Service Manual

ZG
DIAGNOSIS AND TESTING (Continued)

LOAD TEST

A battery load test will verify the battery cranking
capacity. The test is based on the Cold Cranking
Amperage (CCA) rating of the battery. Refer to the
battery label, or see the Battery Classifications and
Ratings chart in Specifications at the back of this
group for the CCA rating of the factory-installed bat-
tery.
WARNING:
•
IF THE BATTERY SHOWS SIGNS OF FREEZ-
ING, LEAKING, LOOSE POSTS, OR LOW ELECTRO-
LYTE LEVEL, DO NOT TEST, ASSIST-BOOST, OR
CHARGE. THE BATTERY MAY ARC INTERNALLY
AND EXPLODE. PERSONAL INJURY AND/OR VEHI-
CLE DAMAGE MAY RESULT.
• EXPLOSIVE HYDROGEN GAS FORMS IN AND
AROUND THE BATTERY. DO NOT SMOKE, USE
FLAME, OR CREATE SPARKS NEAR THE BATTERY.
PERSONAL INJURY AND/OR VEHICLE DAMAGE
MAY RESULT.
•
THE BATTERY CONTAINS SULFURIC ACID,
WHICH IS POISONOUS AND CAUSTIC. AVOID CON-
TACT WITH THE SKIN, EYES, OR CLOTHING. IN
THE EVENT OF CONTACT, FLUSH WITH WATER
AND CALL A PHYSICIAN IMMEDIATELY. KEEP OUT
OF THE REACH OF CHILDREN.
• IF THE BATTERY IS EQUIPPED WITH REMOV-
ABLE CELL CAPS, BE CERTAIN THAT EACH OF
THE CELL CAPS IS IN PLACE AND TIGHT BEFORE
THE BATTERY IS RETURNED TO SERVICE. PER-
SONAL INJURY AND/OR VEHICLE DAMAGE MAY
RESULT FROM LOOSE OR MISSING CELL CAPS.
Before proceeding with this test, completely charge
the battery as described in the Battery Charging pro-
cedure in this group.
(1) Disconnect and isolate both battery cables, neg-
ative cable first. The battery top and posts should be
clean.
(2) Connect a suitable volt-ammeter-load tester
(Fig. 6) to the battery posts (Fig. 7). Refer to the
operating instructions provided with the tester being
used. Check the open-circuit voltage (no load) of the
battery. Open-circuit voltage must be 12.4 volts or
greater.
(3) Rotate the load control knob (carbon pile rheo-
stat) to apply a 300 ampere load to the battery for
fifteen seconds, then return the control knob to the
Off position (Fig. 8). This will remove the surface
charge from the battery.
(4) Allow the battery to stabilize to open-circuit
voltage. It may take up to five minutes for the bat-
tery voltage to stabilize.
(5) Rotate the load control knob to maintain a load
equal to 50% of the CCA rating of the battery (Fig.
9). After fifteen seconds, record the loaded voltage
AMMETER INDUCTION POSITIVE CLAMP CLAMP
Fig. 6 Volt-Ammeter-Load Tester - Typical
Fig. 7 Volt-Ammeter-Load Tester Connections-
Fig. 8 Remove Surface Charge from Battery- Typical
reading, then return the load control knob to the Off
position.
(6) The voltage drop will vary with the battery
temperature at the time of the load test. The battery
temperature can be estimated by using the ambient
temperature during the past several hours. If the
battery has been charged, boosted, or loaded a few
NEGATIVE
BATTERY
Typical
CLAMP
8A - 9