Page 1188 - Workshop Manual - Aumark (BJ1051)

53-12
Battery-Battery

Analysis of common malfunction phenomenon and troubleshooting

1. The battery is stored for a long time so the electricity is insufficient
(a). The fully charged battery will lose electricity gradually if it is not used for a long time, and
we call this phenomenon as “self discharge”. The key reason for self discharge is the
material is not pure. For example, there are impurities inside of pole plate or electrolyte, and
there is potential difference generated between impurity and pole plate, impurity and
impurity; this form closed “partial current” and make the battery discharge.
(b). The material of battery can not absolutely pure, and the positive plate and metal of frame
(lead-stibium alloy) form battery also. So slight self discharging is unavoidable. Improper use will
speed up the discharging. The battery will be discharged completely in 24 hours if the electrolyte
is not pure and content of iron reaches to 1%; electrolyte or other conductive material on battery
cover will connect positive and negative plates and cause self discharge; sulfuric acid will go
down to the bottom if the battery is not used for a long time, so the specific gravity of bottom is
bigger than that of up, which will generate potential difference and cause self discharging.
2. Sulfuration of battery plates
Sulfuration of battery plates means there is a layer of white coarse crystal grain lead sulfate.
Lead sulfate will clog the holes on plate seriously, and it is very difficult for the electrolyte
penetrate the plates, so the battery capacity will be decreased; the conductive performance of
lead sulfate is bad, so the inside resistance of battery is increased greatly; it can not provide
big starting current, so the vehicle can not be started. This kind of coarse crystal grain lead
sulfate is difficult to be dissolved in the electrolyte, so it will not disappear in the normal
charge time. The battery will be scrap when it is vulcanized heavily.
(a). For the phenomenon of sulfuration, cell voltage decreases sharply when it is checked by
high efficient discharge gage; the battery is boiled too early during charging; the specific
gravity of electrolyte increases too slow (even there is no obvious changes); and the
temperature of electrolyte increases rapidly.
(b). The main reason of pole plates sulfuration is the battery is undercharged for a long time or it is not
charged for a long time after it is discharged, and lead sulfate is recrystallized because of the
temperature changes; the liquid level is too low, so the upper part of pole plate contacts with air
and is oxidized (mainly for the negative plate); the electrolyte waves and contact with the oxidized
part of pole plate during vehicle running, it will also generate coarse crystal grain lead sulfate and
vulcanize he upper part of pole plate; specific gravity of electrolyte is too high, electrolyte is not
pure and outside temperature changes sharply will also speed up the sulfuration.
(c). Prevention of plates sulfuration
• Do not store the half discharged battery for a long time; make the battery at full charged state.
• Electrolyte level can not be too low, and make it 10-15mm higher than pole plates; fill in
distilled water as necessary.
• Do not over discharge the battery.
(d). Repair the vulcanized battery
• For slight sulfuration, charge the battery with small current for a long time. That is to
overcharge the battery with the current at the second stage of initial charge continuously
until there are lots of air bubbles generated in the electrolyte and the specific gravity
3
reaches to around 1.280 g / cm .
• For heavier sulfuration, it can be repaired by “water method”. It should be ok when the
discharge capacity reaches to the 80% of rating capacity. Repeat the above charge and
discharge method when the discharge capacity is still very small until the battery is repaired.
• For the very serious sulfuration, replace the battery.
3. Inside short circuit of the battery
(a). Possible reasons of inside short circuit:
• The quality of separator is poor or is damaged, which will let the active material go through
and make positive plate and negative plate contact directly forming short circuit.
• Fallen active material is accumulated too much and make the lower rim of pole plate
contact with sediment forming short circuit.
• Charge current or discharge current is too big, make the pole plate bend, or some
conductive material falls into the battery causing short circuit. Open the battery for
inspection when there is short circuit inside of battery. It will need to replace to a new
separator if it is damaged or penetrated. Clear away the sediment if the fallen active
material is too much. Make the pole plate flat if it is bent.

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