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Workman MD/MDXPage 6 -- 28Electrical System
Battery Charging
To minimize possible damage to the battery and allow
the battery to be fully charged, the slow charging meth-
od is presented here. This charging method can be ac-
complished with a constant current battery charger
which is available in most s hops.
CAUTION
Follow the battery charger manufacturer’s
instructions when using a battery charger.
NOTE: Using specific gravity of the battery cells is the
most accurate method of determining battery condition.
1. Determine the battery charge level from either its
open specific gravity or circuit voltage.
Battery Charge
Level
Specific
Gravity
Open Circuit
Voltage
100% 1.265 12.68
75% 1.225 12.45
50% 1.190 12.24
25% 1.155 12.06
0% 1.120 11.89
2. Determine the charging time and rate using the bat-
tery charger manufacturer’s instructions or the fol-
lowing table.
Battery
Reserve
C
a
p
a
c
i
t
y
Battery Charge Level
(Percent of Fully Charged)
C
a
p
a
c
i
t
y
(Minutes)
75% 50% 25% 0%
80 or
less
3.8 hrs
@
3amps
7.5 hrs
@
3amps
11.3 hrs
@
3amps
15 hrs
@
3amps
81 to 125 5.3 hrs
@
4amps
10.5 hrs
@
4amps
15.8 hrs
@
4amps
21 hrs
@
4amps
126 to
170
5.5 hrs
@
5amps
11 hrs
@
5amps
16.5 hrs
@
5amps
22 hrs
@
5amps
171 to
250
5.8 hrs
@
6amps
11.5 hrs
@
6amps
17.3 hrs
@
6amps
23 hrs
@
6amps
above
250
6hrs
@
10 amps
12 hrs
@
10 amps
18 hrs
@
10 amps
24 hrs
@
10 amps
CAUTION
Do not charge a frozen battery because it can ex-
plode and cause injury. Let the battery warm to
60
o
F (15.5
o
C) before connecting to a charger.
Charge battery in a well--ventilated place to dissi-
pate gases produced from charging. These
gases are explosive.
Keep open flame and electrical spark away from
the battery. Do not smoke. Unplug the charger
from the electrical outlet before connecting or
disconnecting the charger leads from the battery
posts.
Nausea may result if the gases are inhaled.
3. Follow the battery charger manufacturer’s in-
structions. Connect charger cables to the battery.
Make sure a good connection is made.
4. Charge the battery following the battery charger
manufacturer’s instructions.
5. Occasionally check the temperature of the battery
electrolyte. If the temperature exceeds 125
o
F (51.6
o
C)
or the electrolyte is violently gassing or spewing, the
charging rate must be lowered or temporarily stopped.
6. Three (3) hours prior to the end of the charging, mea-
sure the specific gravity of a battery cell once per hour.
The battery is fully charged when the cells are gassing
freely at a low charging rate and there is less than a
0.003 change in specific gravity for three (3) consecu-
tive readings.
Battery Storage
If the vehicle will be stored for more than 30 days, re-
move the battery and charge it fully. Either store it on the
shelf or on the vehicle. Leave the cables disconnected
if it is stored on the vehicle. Store the battery in a cool
atmosphere to avoid quick deterioration of the charge in
the battery. To prevent the battery from freezing, make
sure it is fully charged.