Gravely Promaster 260Z Service Manual page 27

IMPORTANT: When distilled water is added to battery
during freezing weather, battery must be charged to
mix water with electrolyte, or water will remain at top
and freeze.
Battery Charger
Under normal conditions, the engine alternator will
have no problem keeping battery charged. When unit
has set for an extended period of time without
operation and the battery has been completely
discharged, a battery charger will be required for
recharging.
Before using a charger, an attempt can be made to
recharge the battery using the engine alternator by
jump starting the unit and allowing the engine to run.
Charging A New Battery
WARNING: FROZEN BATTERIES CAN
EXPLODE and result in death or serious
injury.
DO NOT charge a frozen battery. Let the
battery thaw out before putting on a charger.
IMPORTANT: DO NOT fast charge. Charging at a
higher rate will damage or destroy battery.
ALWAYS follow information provided on battery by
battery manufacturer. Contact battery manufacturer for
extensive instructions to charge battery.
3
2
1. Positive terminal
2. Negative terminal
Figure 20
1. Put unit into service position to gain access to
battery.
2. Disconnect negative (-) cable first, then positive (+)
cable.
3. Remove hold down and remove battery.
4. Place battery on bench or other well ventilated
place where electrolyte spill will not create
damage.
5. Remove caps and fill each cell to level indicated
with electrolyte at 1.230 ± specific gravity and 80
degrees F (27 degrees C).
6. Let battery stand for one half hour.
7. Check electrolyte level and add more if necessary.
1
3. Battery
OF1670
9 - 27
8. Connect positive (+) lead of charger to positive (+)
terminal, and negative (-) lead to negative (-)
terminal.
9. Charge the battery at two and a half amps for ten
hours or until all cells are gassing freely and the
specific gravity is constant over three 30 minute
intervals.
10.Immediately after charging, check the electrolyte
level. If low, add distilled water to bring cell up to
required level.
11.Replace caps finger tight, wash off and dry battery.
12.Reinstall battery into unit and connect positive (+)
cable first, then negative (-) cable.
Specific Gravity Check
The specific gravity should be checked with a
hydrometer.
NOTE: The specific gravity should be checked in each
cell and should be the same for all cells. A variation in a
cell reading could be an indication of a problem. Sub-
tract .004 from 1.265 for each 10
.004 to 1.265 for each 10
A special temperature compensated hydrometer is
used to read the battery's state of charge.
The reading on the hydrometer gauge should be above
1.225. If the reading falls below 1.225 specific gravity
there will be an insufficient charge.
ALWAYS charge the battery until the specific gravity of
1.265 is reached over 3 successive readings. Check
monthly to ensure charge is maintained. The
approximate state of charge can be determined by the
cell specific gravity of the rested open circuit voltage at
room temperature and the charging time can be
estimated. For example:
OCV Specific
Gravity
12.60 1.265
12.4 1.225
12.20 1.180
12.00 1.130
11.80 1.100
If using an automatic tapering 12 volt charger, choosing
a good quality 5 to 10 amps 15VDC minimum output
charger and charge for 3 to 12 hours according to the
battery state of charge (see table above) or until the
specific gravity in each cell reaches 1.255 - 1.265
specific gravity at 80 degrees F.
If using a constant current charger, charge at 1 to 2
amperes for the time given on the table above or until
full specific gravity is reached.
o o
F below 80 F or add
o o
F above 80 F.
% of Charging
Charge Time
100% ---
75% 3 hours
50% 7 hours
25% 10 hours
0% 12 hours