Hitachi UC 14YFA, Технические данные и руководство по обслуживанию

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Q2 Why was the microcomputer control system adopted for the Model UC 14YFA?
A2 If charging is continued after the battery has been fully charged, it will cause a large amount of oxygen gas
(O
2
) to be generated in a short period of time, as shown below. This proportionately accelerates
degradation of the plates.
The microcomputer control system was adopted for the Model UC 14YFA charger in order to stop
charging immediately before the battery is fully charged, thereby avoiding the generation of oxygen gas.
This charging method applies no stress to the batteries.
Anode plate
Up to full charge. (Charging
proceeds almost without
deviation.)
Charged portion Uncharged portion
Plates
Separator
Cathode plate
O
2
O
2
O
2
Oxygen gas is generated
when full charge is reached.
(Anode is fully charged.) Enters overcharge state and
begins gas degradation with the
cathode.
Anode plate
Cathode plate Cathode plate
Anode plate
O
2
O
2
O
2
Q3 What is the difference between the microcomputer control system and the dT/dt system?
A3 Both systems cut off charging at almost the same point before the battery becomes fully charged.
The microcomputer control system detects a sudden voltage change which occurs just before the
battery is fully charged and then suspends charging. The dT/dt system detects a sudden temperature rise
which occurs just before the battery is fully charged and then suspends charging.
Q4 Is there any difference in the amount of work possible per charge of batteries charged with the
microcomputer control system and those charged with dT/dt microcomputer control system?
A4 The dT/dt microcomputer control system may have a slightly shorter charging capacity (approx. 3 to 5 %).
However, the amount of work possible per charge varies widely depending on the ambient temperature, the
efficiency with which the battery charge is used, etc., so that there is essentially no difference between
batteries charged with either system.
Q5 The battery charger is supposed to be used within a temperature range of 0 to 40 ˚C.
What happens if it is used for charging at under 0 ˚C or above 40 ˚C?
A5 If charging is attempted when the ambient temperature is below 0 ˚C, charging is not possible or
overcharging occurs because the recharging control circuit does not function properly. If charging is
attempted when the ambient temperature is above 40 ˚C, charging is stopped before the battery is fully
charged due to temperature rise during charging because the difference between the upper limit of the
rechargeable battery temperature (Ni-Cd batteries: 60 ˚C, Ni-MH batteries: 55 ˚C) and the ambient
temperature is small.