Page 1189 - Workshop Manual - Aumark (BJ1051)

53-13
Battery-Battery
(b). Main character of pole plate short circuit is low open circuit voltage and small capacity. Terminal
voltage of cell decreases to 0 rapidly when it is checked by high efficient discharge gage. During
charging, the terminal voltage increases very slow, and the specific gravity of electrolyte increases
very slow too; there is less or no air bubble in the later period of charge.
4. Battery pole plates are bent
The positive plate of battery is easy to be bent but the negative plate is not bent easily; even
there is negative plate bent, it is because the positive plate is bent too much. The main
reasons of pole plate bent are:
(a). Poor quality. Diachylon is not coated evenly during manufacturing, and this will make the
active material distribute unevenly. So electrochemistry actions caused by pole plate during
charging and discharging are different, this will make the expansion and constriction of pole
plates different, which will make plate bend even break.
(b). Big current discharge frequently, so the current densities of pole plate surface are different
and the expansions of active material are different, which will make the plate bend.
(c). There is sulfuric acid generated inside of deep layer of pole plate because of frequent over
discharge, and it can not be resumed during charging; so it will cause inside expansion and
make the plate bend.
5. A great deal of active material falls down from pole plate
The phenomenon of active material falls down normally happened on positive plate. It can
not be avoided for the active material falling down because the volume of active material
changes during battery charging and discharging. It will speed up the falling down of active
material if the battery is not used correctly.
The main reasons of active material falling down:
(a). Charge current is too big, and this will make the temperature of electrolyte is too high; the
active material is expanded and soften to fall down.
(b). The battery is over charged frequently. There is a great deal of air venting from the hole of pole
plates which will form pressure inside of plate holes and make the active material fall down.
(c). Discharge current is too big and the time connecting to starter is too long will bend the plate
and speed up the fall down of active material.
(d). It is not charged in time after discharge in winter, so the electrolyte is iced when its specific
gravity is too low.
(e). Battery is vibrated heavily during vehicle running.
6. Polarity of one cell is reversed
(a). The reason is that there is malfunction of this cell or by other reason the capacity is
decreased. The cell with low capacity will be first discharged to 0 during battery discharging. 53
The current discharged by other cells will charge it if the battery is discharged continuously
and its polarity will be reversed. In three cells, if the polarity of one cell is reversed, the
terminal voltage is 2 V but not 6V when the battery is checked by voltmeter.
(b). In order to prevent this phenomenon happening, the cell with low capacity should be
charged/discharged independently or replace the pole plates; it can be used when its capacity
is same or similar with the capacities of other cells.
7. Battery explosion
The main reason of battery explosion is that when the battery is over charged, there is a
great deal of air bubbles generated because the water inside electrolyte is decomposed into
hydrogen and oxygen; inside short circuit of battery and sulfuration malfunction;
temperature of electrolyte increases sharply during charging make the water evaporate a lot;
now if the ventilation hole of filling cap is clogged or the gas is too much that can not vent,
the battery will explode when the inside pressure reaches to a certain limit (or meet fire).
The method to prevent battery explosion are:
(a). Keep the ventilation hole of fill cap free.
(b). Wire connection on the pole should be firm to prevent fire generating.
(c). Open the ventilation hole of fill cap when it is checked by High efficient discharge gage.
(d). Control the charge and do not over charge to decrease the gas quantity. No fire inside of
battery charging room and keep the room ventilated.

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