Lesson 2/Learning Event 2
Check the specific gravity of the battery often while it is being charged. Just how often will
depend on the rate of charge. If a charge rate of 2 amperes for 2HN batteries or 5 amperes for
6TN batteries is being used, check the gravity hourly when the batteries near full charge. You may
reduce the time between checks if the charge rate is decreased. Add water to replace any lost
during the charge. A battery is fully charged when three successive readings show no further rise
in specific gravity.
When the battery is charged, remove it from the charger and clean its top to remove any acid.
Inspect the battery once again for any cracks that may have opened due to the charging process.
Screw the vent plugs tightly in place. If the battery has handles and the paint on them is worn,
apply a coat of acid-resistant black paint.
PLACING BATTERIES IN SERVICE
New batteries that you receive will probably be charged and dry. If they are, you will have to fill
them with electrolyte in preparing them for service. The instructions received with new batteries
on how to prepare them for service should always be followed. In general, the following
Remove and discard the seals from the ventholes of the vent plugs. Remove the vent plugs and fill
each cell with electrolyte to the proper level. The temperature of the battery must be at least 60F.
Let the battery stand for 30 minutes after filling to allow the plates and separators to become
soaked, then check the specific gravity of each cell. The electrolyte level must be correct.
The battery is now ready for use unless one or more of the following conditions exist:
The specific gravity of any cell is below 1.250 after the 30-minute stand.
The battery will not be used for 12 hours after filling.
The battery is going into service in temperatures below zero.
If any of the above conditions exists, the battery must be charged. If you have the time and
equipment, it is always best to charge the battery regardless of the conditions to ensure longer
service life. After charging, the specific gravity should be at or very near 1.280.