Table of Contents
Advertisement
6.1 OVERVOLTAGE protection
This circuit monitors the value of the output voltage of the charging unit. lf the output voltage exceeds the
pre-set upper threshold, the red LED OVERVOLTAGE lights up, the charging unit is disconnected from
battery and consumers automatically, activating the error message. Thereby the battery remains connec-
ted to the consumer, supplying it until the failure has been remedied. This proection circuit prevents an
inadmissible increase of the battery voltage and the resultant gassing of Ihe battery with a possible failure
in the charging unit (protection against danger of explosion through detonating gas).
6.2 LOW VOLTAGE monitoring
The battery voltage is monitored in the case of discharge. lf the voltage falls belowthe pre-set threshold
of 22 V, the red LED LOW VOLTAGE lights up. Once the mains voltage is back, the battery is re-charged
automatically. lf the battery voltage does not reach the adjusted threshold of 25.5 V within the given
charging time of approx. 8 h after a mains failure, and the red LED LOW VOLTAGE does not go out this
probably means a battery malfunction and an error message is activated.
6.3 LINE VOLTAGE monitoring
The green LED LINE VO LTAGE goes off in the case of mains failure and an error message is activated.
6.4 BATTERY VOLTAGE monitoring
The battery voltage is monitored with this circuit. lf the battery is alright the green LED BATTERY
VOLTAGE lights up. lf the battery voltage drops below the value of 19.5 V, the battery is discharged, all
LEDs are off, an error message is activaed, the battery is disconnected from all consumers and thus
reliably protected against exhaustive discharging. The exhaustive discharge protection only works with
the battery modules DEM 315, DEM 316 and DEM 317 (also see Sections 5.1 and 5.2).
6.5 CHARGE CURRENT monitoring
This is for monitoring the battery charge circuit. Errors like broken wires or missing batteries are
recognized. When the battery charge current falls below the threshold of 150mA (25mA solder-change-
able), the battery charger briefly loads the battery to check whether a minimum current of at least 30mA
flows from the battery to the charger. The green LED (3) CHARGE CURRENT is dimmed in case the
threshold is not reached and the fault message is activated. This test sequence runs approximately every
60 seconds.
6.6 Reverse voltage and short-circuit protection
Reverse volltage protection prevents damage which may be caused by possible polarisation errors when
the battery is connected to the charging unit. The short-circuit protection disconnects the battery from the
charging unit in the event of shorted cells or total short-circuit. The output fuse F 503 (see Figure 3) in the
charging unit blows in this case and must be replaced by a slo-blo fuse with the rating 4A (T4A). In the
event of a blown fuse, the green LED (3) CHARGE CURRENT goes out and an error message is activated.
6.7 Collective failure signal
The collective failure signal is designed as a floating contact, making available malfunctions of the battery
such as: disconnection at LOW VOLTAGE, wrong polarity or battery short-circuit, as well as malfunctions
of the charging unit such as: absence of LINE VOLTAGE, OVERVOLTAGE or failures in the charging
circuit CHARGE CURRENT for long-range transmission. The corresponding failure is indicated on the
unit itself via the corresponding LED (3) lighting up or going off respectively,(see page 2 as well as Section
6.1 to 6.6). The floating contact of the collective failure indication is wired at the D-sub pin connector
BATTERY CONTROL (9) (see Figure 2).
21
Advertisement
Table of Contents
