SIEMENS
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Siemens KT 10.1 · 2016
15
Technical information and configuration
Battery charging with SITOP
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Overview
Battery charging with SITOP power supplies
The SITOP PSU300B 12 V/20 A (article number
6EP1424-3BA00), 24 V/17 A (article number 6EP1436-3BA20)
and 24 V/30 A (article number 6EP1437-3BA20) power supplies
are suitable for charging lead-acid batteries. In the case of a
V/I characteristic set for parallel operation, the battery will be
charged with a constant current until approximately 95% of the
set SITOP output voltage has been achieved. The charging cur-
rent is then continuously reduced from 1.2 x rated current at 95%
of the set voltage to approximately 0 A or the self-discharge
_current of the battery at 100% of the set output voltage, that is,
resistance characteristic in this range.
As reverse voltage protection and polarity reversal protection,
we recommend that a diode suitable for at least 1.2 x rated cur-
rent of the power supply with a blocking voltage of at least 40 V
is connected in series with the "+" output (anode connected to
"+" output of the SITOP PSU300B and cathode connected to
positive pole of the battery).
The output voltage of the power supply must be set at no-load to
the end-of-charge voltage plus the voltage drop at the diode. For
an end-of-charge voltage of e.g. 27.0 V DC (usual at 20 °C to
30 °C battery temperature; specifications of the battery manu-
facturer must be observed!) and 0.8 V voltage drop at the diode,
the power supply must be set to 27.8 V during no-load opera-
tion.
General note for using SITOP power supplies as a
battery-charging unit
When using SITOP as a battery charging unit, VDE 0510 or
relevant national regulations must be observed, and adequate
ventilation of the battery location provided. SITOP power
supplies are designed as rack-mounting units, and protection
against electric shock should therefore be provided by installa-
tion in an appropriate housing.
The value recommended by the battery manufacturer must be
set as the end-of-charge voltage (depending on the battery tem-
perature). An ideal temperature for the lead-acid battery is be-
tween +20 °C to +30 °C and the recommended end-of-charge
voltage in this case is usually about 27 V.
© Siemens AG 2016