DAF CF65, CF75, CF85 Series . Manual — part 684

5

CF65/75/85 series

Charging batteries

BATTERIES

2-1

2. CHARGING BATTERIES

2.1 GENERAL

-

A battery may only be charged using DC
current. Connect the positive pole of the
battery to the positive terminal (+) of the
charger, and the negative pole of the battery
to the negative terminal (--) of the charger.
The cell sealing plugs may remain on the
battery during charging (with the exception
of fast charging).
The cell voltage will rise during charging.
This increase in voltage depends on the
charging current applied and the
temperature. During normal charging, the
cell voltage will rise from about 2 volts/cell
to about 2.65 volts/cell. If a charging voltage
of about 2.35 to 2.4 volts/cell (about 14.2
volts in a 12V battery) is exceeded, this will
initiate active gas development.
As a consequence of the rise in voltage
during charging, the charging current will
gradually fall, as a rule.
Overcharging will reduce the service life of
a battery.

-

If the charging of the battery is continued
after it has been fully charged (even with a
low current), this will lead to corrosion
(corrosive attack) of the grids of the positive
battery plates. This type of wear leads to
premature redundancy of the battery.
Depending on the capacity of the charger,
the normal charging time is between 8 and
15 hours.
If during charging, the temperature of the
battery acid exceeds 55

_C, charging should

be stopped. High temperatures reduce the
service life of the battery.

4

0202

5

BATTERIES

Charging batteries

CF65/75/85 series

2-2

-

A battery should be considered to be
charged when the charge voltage stops
rising for a period 2 hours and the acid
density (relative density) has reached the
nominal value (for example 1.28 kg/dm

3

)

and it rises no further.

-

A charged battery must be used
immediately. If this is not possible, maintain
the battery as described in the “Storage of
batteries” section.

-

A discharged battery must be charged as
soon as possible. If a discharged battery is
not recharged, the battery plates may
become sulphated (i.e. they may become
hard), which will lead to permanent loss of
capacity.

-

Never disconnect the battery terminals
when the engine is running to prevent
damage to electronic components.

-

Connect the positive lead (+) of the battery
charger to the positive terminal (+) of the
battery first and then the negative lead (--)
to the negative terminal (--).

-

Switch off the battery charger before
disconnecting the battery charger leads, to
avoid sparking and to eliminate the risk of
explosion.

-

To disconnect, release the negative terminal
(--) first and then the positive terminal (+).

4

0202

5

CF65/75/85 series

Charging batteries

BATTERIES

2-3

2.2 METHODS OF CHARGING

Always disconnect the battery
terminals before charging.

Normal charging
-

Normal charging is done to partially or fully
restore discharged batteries to full capacity.
In most cases, a charging current of

1

/

20

to

1

/

10

of the capacity is selected.

-

It is important to reduce the charging
current during gas development and to
switch the charger off when the battery is
charged.

Fast charging
-

With this method, multiples of the normal
charge current (approx. 3 to 5 times) are
used to achieve an acceptable charge
condition in the shortest possible time.

-

Before fast charging, remove the battery
leads to prevent damage to the electronic
components.

-

Remove the cell sealing plugs so that the
released gases can easily escape.

-

To prevent overcharging, switch to a lower
charging current when the cell voltage is
reached (2.35 to 2.4 volts/cell).

Note:
If possible, avoid fast charging. Only use it
in exceptional cases. Fast charging causes
battery overloading, which reduces the
service life of the battery.

4

0202

5

BATTERIES

Charging batteries

CF65/75/85 series

2-4

Buffer charging
-

With this method, the consumer and the
charger are both connected to the battery.
The charger delivers sufficient current to
ensure that the battery remains virtually fully
charged. The battery will deliver peak
currents to the consumer.

-

Buffer charging is best done at a constant
(stabilised) voltage.

Trickle charging
-

A fully charged battery that is not used for
some time, will start to discharge of its own
accord. It may discharge at a rate of 0.1%
to 1% per day. Trickle charging
compensates for such discharges.

-

The charging current for trickle charging
should be around 0.1 A per 100 Ah.

4

0202