TCM FB-8 Series, Service Manual

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1.1 GENERAL DESCRIPTION
1.1.1 BATTERY
The battery unit consists of twenty-four 2-volt battery cells for the 48-volt electrical system
(thirty-six 2-volt battery cells for the 72-volt electrical system) connected in series. Figure 1.1
shows its construction.
Fig. 1.1 Battery Unit
BATTERY CELL WITH
ELECTROLYTE LEVEL SENSOR
LOCK PIN
ELECTROLYTE
LEVEL INDICATOR
Note: The sketch shows a 48-volt battery unit. The 72-volt battery unit has 36 battery cells.
(1) Battery care
The most important point in battery care is to
prevent overdischarge. The deeper the battery
discharges, the shorter its life becomes (See Figure
1.2).
The approximate depth of discharge can be
known by measuring the specific gravity of the
electrolyte (See Figure 1.3)
Check the level of electrolyte every ten days.
Add distilled water if the level is found lower than
the specified level before charging the battery.
Fig. 1.2 Relation Between Depth of Discharge
and Service Life (Example)
Service life
Cycles of charge and discharge
Depth of discharge (%)
1. BATTERY AND CHARGER (OPTION)