18
Operation
Measuring the specific Gravity of Battery Acid
In a maintenance-free battery the acid specific gravity (SG) cannot be measured.
If charging status is not satisfactory, charge the battery once more.
In conventional, non maintenance-free batteries the SG can be specified with an
acid pipette. The range should be at least 1.25 up to 1.28 g/cm
3
.
The SG in a well-conditioned battery has to be equal in all 6 cells. When the
density in the cells is different - the highest and the lowest value – and vary up to
more than 0.025 (25 points), this might be a hint for possible problems in the
cells.
When the SG does not show the same state after recharging the battery, the
battery might have sulphurized. If the value remains below 1.24 g/cm
3
- even after
charging - the battery is discharged and should be replaced. A battery is used up
after approx. 5 – 8 years.
Starter Test
With this test you can easily measure whether the starter motor of the vehicle
does not take too much current from the battery. In some cases currents of about
200 Ampere can be produced and weak the battery.
Before performing this test, the battery load test has to be made and the battery’s
condition should be OK.
1. Pull the spark plug cables from the spark plug in order to avoid the engine to
get started.
2. Now turn the key to try to start the engine.
3.
DO NOT
press the testing switch during this test! Only check the voltmeter (7)
and read the decreasing voltage value during the starting time.
SG of Battery Acid in
g/cm
3
Charging State
Step
1,25 – 1,28
Charged
Perform Measurement
1,20 – 1,24
Semi charged
Charging is recommended
< 1,20
Insufficiently charged
Charge immediately
