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SECTION 55 -- ELECTRICAL SYSTEM -- CHAPTER 5
603.54.471.00 -- 11 -- 2004
BATTERY PROBLEMS -- FREQUENT
CAUSES
1. Internal open circuit.
2. Internal short--circuit.
3. Battery electrolyte leakage.
4. Grid active material separation.
5. Accumulation of sulphate crystals too big to be
dispersed.
These problems are commonly caused by the
following:
1. Component failure inside the elements.
2. Excessive crystal growth which can pierce the
spacers and cause short circuits.
3. Excessive overload (bad charging system, high
voltage fast charging, high operating
temperatures).
4. Battery electrolyte freezing.
A fully charged battery freezes at --65 ° C
(--85 °F). A 50% charged battery freezes
between --17 °C and --27 °C (16.6 °F). A
completely flat battery freezes between -- 3 °C
(26.6 °F) and --11 °C (12.2 °F). Excessively fast
charging and boiling caused by gas formation
cause the separation of active material from the
grids. Separation destroys the battery chemical
function.
5. Crystals are formed when batteries are left flat.
High temperature and long periods with the
battery flat increase this condition. If a battery is
left at room temperature for a week it can rarely
be charged in the vehicle. Battery recharge
requires higher constant voltage. After three
weeks the battery will be permanently
jeopardized and it will be necessary to follow the
procedure described for “very flat batteries”.
Fully charged batteries have longer a life. A
lead--calcium battery discharges 3% a month. This
means that in 16 months it will reach 50% charge. In
the tractor , inactive load is approximately 50 mA. To
forecast discharge on a vehicle not in use add
approximately 8 Ah a week to this value.
It is worth noting that if a battery is weak during
engine start--up, it is best to let the battery rest for two
minutes. This rest time increases as the temperature
decreases.
When two batteries are installed, do not use an old
battery with a new one. One battery will always stop
before the other one. If the battery has lasted as
forecasted, charge both batteries. If one has stopped
before the forecasted time due to a defect, then
change only the defective battery.
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