11(12)
Datum/Date
Rev
Dokumentnr/Documentnr
Uppgjord/Prepared
Dokansv/Godkänd - Doc respons/Approved
Kontr/Checked
Tillhör/Referens-File/Reference
98-11-20
G
1531-BML 351 013 Uen
INSTALLATION INSTRUCTION
Faktaansvarig - Subject responsible
11
BATTERY BACK UP
For the BusinessPhone 250 there are 2 different types
of battery back up units. The AC/DC switcher
converter BML 351 013/x is used to charge the
batteries, deliver power to the exchange and switch
over to emergency powering from the connected
battery in case of mains power failure.
When the system is running on batteries the
BML 351 013/x provides an under voltage trip to
disconnect the batteries after the 44 volt limithas been
reached. Thus deep discharge of the batteries is
prevented.
Handling batteries is a delicate job and requires
thought and care. Batteries do NOT last for ever, but
with the right treatment they will serve a long time
without any trouble.
Both battery back-up units use sealed batteries that do
not require any service, however batteries must not be
subjected to high temperatures, which reduces their
lifetime and batteries should NOT be left uncharged
after a discharge cycle, as this may destroy the
batteries permanently.
So charge them again as soon as possible after the
power failure. If the batteries are completely
discharged and it is not possible to charge them, turn
off the circuit breaker on the battery unit to prevent
deep discharging and charge them again as soon as
possible.
Under normal operating conditions this will not be a
problem as battery charging commences as soon as
the mains returns. If the batteries have to be left
discharged the circuit breaker should be turned off.
Back up time
Measurements on back up time have been taken from
the different battery back up units. The value stated
within brackets () are the available line currents.
Power consumption for all boards in the cabinet and
battery charging have been deduced from the figure
within brackets.
The small battery back up unit (BKB 201 001) is used
to supply up to 6 boards and the battery cabinet
(BKB 201 001) is used to supply a fully equipped
cabinet with 9 boards.
BKB 201 001
This is the smaller integrated unit with the batteries located inside the exchange cabinet (in position 6),
occupying 3 board slots. The back up time for 3 different current loads are shown below.
A system with 53 DBC 203 telephones uses 2.5 Amp (1.6 Amp) from the battery.
A system with 33 DBC 203 telephones uses 1.9 Amp (1 Amp) from the battery.
A system with 13 DBC 203 telephones uses 1.3 Amp (0.4 Amp) from the battery.
48 V
47 V
46 V
45 V
44 V
0
10
20
30
40
50
60
70
Minutes
Battery
voltage
1.3A
2.5A
1.9A
Battery low voltage limit