Hitachi uc 24yj Technical Data And Service Manual page 13

5-3-6. Switching the charging current
The charging current is switched according to the temperature of the battery or the charger as described in (1) to
(6) below (see Figs. 7 to 12).
(1) 7.2 V to 24 V Ni-Cd batteries
The charging current is switched (9 A/7.5 A/6 A/1.3 A) according to the battery temperature at the start of
charging.
(Min.)
In the case of 2.0 Ah Ni-Cd batteries Models EB 7B/EB 9B/EB 9M/EB 12B/EB 1220BL/EB 12M/EB 14B
Fig. 7 Relationship between battery temperature at the start of charging,
Relationship between temperature of battery/charger and charging current
Temperature
Battery temperature at the start of
charging is between -5˚C and 50˚C.
Battery temperature at the start of charging
is 50˚C or more.
Battery temperature at the start of charging
is -5˚C or less.
Inside of the charger becomes hot during
charging at 9 A (see Fig. 13).
(*) The battery is also charged at 1.3 A when the battery is near the end of its service life.
Otherwise, the battery temperature becomes high due to the high internal resistance and it is dangerous.
(2) 18 V Ni-Cd batteries
The charging current is switched (7.5 A/5 A/1.3 A) according to the battery temperature at the start of charging.
(Min.)
Fig. 8 Relationship between battery temperature at the start of charging,
Battery temperature at the start of charging
charging time and current
Battery temperature at the start of charging
In the case of 2.0 Ah Ni-Cd batteries Models EB 1820/EB 18B
charging time and current
Charging current (constant value)
Charging time
Charging current
9 A
7.5 A
1.3 A (*)
Switch from 9 A to 6 A
Charging current (constant value)
Charging time
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Purpose
Protection of the battery
Protection of the charger