Thales 421, Operation And Maintenance, Page: 162 / 256

LLZ 421
Maintenance Operation and Maintenance
ILS 420
6−20
Ed. 01.10 SOAC
If a temperature of 50 °C is reached, a cooling period should be allowed until the temperature has
dropped to 35 °C again. The battery is ready for service when the nominal values have been reached
and each cell has the correct acid level (max. marking of acid level indicator). Finally the outside of
the battery should be cleaned with water to remove acid and dirt. The battery should then be installed
immediately in the navigation installation, and operated in standby parallel mode. This procedure en-
sures that the battery is always charged, but that it is not operated close to the gassing level. The
charge characteristic of the BCPS (current/voltage characteristic or I−U characteristic) ensures that
the limit values specified by the battery manufacturer are conformed with, including subsequently
charging and discharging operation. No further measures are necessary.
NOTE: Each battery cell/battery must have the same charge or discharge state on account of the
series connection.
The following table summarizes the procedure.
No. Procedure Duration
in hrs
Remarks
1 Filling with acid − See 6.4.1.2 (Preliminary Operations). Unscrew inspec-
tion plugs, but leave over the hole in order to prevent
contamination whilst allowing gas to escape.
2 Interval 2
3 Density measurements − The density provides information on the state of plates.
Densities less than 1.15 kg/l mean that the battery has
been stored for a long time or is not precharged. A
higher charging current can be used in such cases.
4 Charging as per data, see
also
WARNING note in sec-
tion 6.4.1.3.4 .
6 ... 55 The acid density and battery voltage should be mea-
sured every 1 or 2 hours. Note the values and compare
with previous measurements and nominal values.
When the nominal values are reached, stop charging
and continue at No. 5 in this table.
5 Interval 1
6 Acid level correction − With purified water.
7 Charging with data as No. 4
in this table 2 Repeat Nos. 7 to 9 until the acid density and battery
voltage cease to change when the previous measure-
ments, and the nominal values are reached.
8 Interval 1
9 Acid density and battery
voltage measurements −
10 Set acid density and acid
level to nominal values.
Screw on inspection plugs. − If corrections are necessary, recommence at No. 7.
11 Clean battery with water (ex-
ternal surfaces) and grease
poles. − See 6.4.1.2.4 (basic rules for handling batteries).
12 Operate battery in standby
parallel mode. −