3-30
ELECTRICAL
3. Remove:
• Battery band
•Battery
4. Measure:
• Battery charge
Measurement steps:
a. Connect a pocket tester "1" to the
battery terminals.
• The charge state of an MF battery
can be checked by measuring its
open-circuit voltage (i.e., the volt-
age when the positive terminal is
disconnected).
• No charging is necessary when the
opencircuit voltage equals or ex-
ceeds 12.8 V.
b. Check the charge of the battery,
as shown in the charts and the fol-
lowing example.
Example
Open-circuit voltage = 12.0 V
Charging time = 6.5 hours
Charge of the battery = 20–30%
A. Relationship between the
open-circuit voltage and the
charging time at 20 °C (68 °F)
(These values vary with the
temperature, the condition of
the battery plates, and the
electrolyte level.)
B. Open-circuit voltage
C. Charging time (hours)
D. Time (minutes)
E. Charging condition of the bat-
tery
F. Ambient temperature 20 °C
(68 °F)
a. Charging
b. Check the open-circuit volt-
age
5. Charge:
•Battery
(refer to the appropriate charging
method illustration)
Do not quick charge a battery.
• Never remove the MF battery
sealing caps.
• Do not use a high-rate battery
charger since it forces a high-
amperage current into the bat-
tery quickly and can cause bat-
tery overheating and battery
plate damage.
• If it is impossible to regulate the
charging current on the battery
charger, be careful not to over-
charge the battery.
• When charging a battery, be sure
to remove it from the machine. (If
charging has to be done with the
battery mounted on the machine,
disconnect the negative battery
lead from the battery terminal.)• To reduce the chance of sparks,
do not plug in the battery charger
until the battery charger leads
are connected to the battery.
• Before removing the battery
charger lead clips from the bat-
tery terminals, be sure to turn off
the battery charger.
• Make sure the battery charger
lead clips are in full contact with
the battery terminal and that they
are not shorted. A corroded bat-
tery charger lead clip may gener-
ate heat in the contact area and a
weak clip spring may cause
sparks.
• If the battery becomes hot to the
touch at any time during the
charging process, disconnect
the battery charger and let the
battery cool before reconnecting
it. Hot batteries can explode!
• As shown in the following illus-
tration, the open-circuit voltage
of an MF battery stabilizes about
30 minutes after charging has
been completed. Therefore, wait
30 minutes after charging is com-
pleted before measuring the
open-circuit voltage.
Tester positive probe→battery
positive terminal
Tester negative probe→battery
negative terminal
