2. Add water, as necessary, to each cell.
available charging equipment does not have the
3. Connect the battery to the charging panel.
desired charging rates, use the nearest available
Make sure the connections are clean and
rates. However, do not let the rate become so high
that violent gassing occurs. NEVER ALLOW
THE TEMPERATURE OF THE ELECTRO-
4. Turn on the charging circuit. Set the cur-
rent through the battery at the value given
LYTE IN ANY CELL TO RISE ABOVE 125°F
as the starting rate.
5. Check the temperature and specific gravity
of pilot cells hourly.
6. When the battery begins to gas freely,
reduce the charging current to the finishing
Continue the charge until the battery is fully
charged. Take frequent readings of specific
gravity during the charge. Correct these readings
A normal charge is complete when the specific
to 80°F. Then, compare them with the reading
gravity corrected for temperature has reached a
taken before the battery was placed on charge.
value within 5 points (0.005) of the specific gravity
If you know the rise in specific gravity in points
obtained on the previous equalizing charge.
per amp-hr, the approximate time in hours
required to complete the charge is as follows:
Rise in specific gravity in
An equalizing charge is an extended normal
points to complete charge
charge given only at the finishing rate. You should
Rise in specific gravity in × Charging rate
periodically conduct an equalizing charge to
points per amp-hr
ensure all the sulfate is driven from the plates and
all the cells are restored to a uniform maximum
until the hydrometer readings show no increase
in corrected specific gravity for any cell over a
The test discharge is the best method of
period of 4 hours. You should take the readings
determining the capacity of a battery. Most
every 30 minutes.
battery switchboards are provided with equipment
for giving test discharges. If proper equipment is
not available, a tender, a repair ship, or a shore
station may perform the test discharge. A battery
test discharge is required when one of the follow-
You may maintain a battery at full charge by
connecting it across a charging source that has a
ing conditions exists:
voltage maintained within the limits of from 2.13
to 2.17 volts per cell of the battery. In a floating
1. A functional test reveals a low output.
charge, you determine the charging rate by the
2. One or more cells are found to have less
battery voltage rather than by a definite current
than normal voltage after an equalizing
value. Maintain the voltage between 2.13 and 2.17
3. A battery cannot be brought to within 10
volts per cell with an average as close to 2.15 volts
points of normal charge of its specific
4. A battery has been in service 4 years.
Use an emergency charge when a battery must
An equalizing charge must always precede a
be recharged in the shortest possible time. Start
battery is discharged at its 10-hour rate. This is
the charge at a much higher rate than is normally
used for charging. Use it only in an emergency.
done until the total battery voltage drops to a
value equal to 1.75 times the number of cells in
This type of charge may be harmful to the battery.
series or the voltage of any individual cell drops
to 1.65 volts. Keep the rate of discharge constant
throughout the test discharge. Because standard
Normally, the charging rate of Navy storage
batteries are rated at the 10-hour capacity, the
batteries is given on the battery nameplate. If the
discharge rate for a 100 amp-hr battery is 100/10,