Bosch BAT 251 Manual Original página 18

en 18 | BA� 2�1 | Operation
�.� Back-up mode
"Back-up mode" can be used to supply power to the ve-
hicle electrical system (e.g. when changing the battery)
to prevent data from being lost.
1. Connect the terminal clips to the terminals on the
vehicle battery.
2. Press and hold down the ON/OFF button (Fig. 2,
Pos. 2) for 2 s.
 LED 6 lights up yellow. Back-up mode is switched
on.
!
The terminal clips are now live. The BAT 251 switch-
es back-up mode off automatically if the power input
exceeds 50 Ampere.
3. Press the ON/OFF button (Fig. 2, Pos. 2) to switch
off back-up mode.
�.4 Starting from back-up mode
If you have selected back-up mode and then wish to
start the engine, this can only be done within the first
minute.
¶
Start the vehicle.
i
The BAT 251 automatically switches from back-up
mode to start-up mode.
"
LED 6 changes from yellow to green.
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1 689 979 900 2012-10-18
6. Testing and charging the
internal battery
i
Always charge the BAT 251 regularly.
i
Do not store the BAT 251 with a partially discharged
battery.
6.1 Internal battery test
Each time it is switched on, the BAT 251 checks the
charge status of its battery. The LEDs �, 4 or � indicate
the charge status of the BA� 2�1 battery.
Pos. LED Color Meaning
3 green Internal battery fully charged
4 yellow Internal battery partially discharged. Start-
ing possible, but internal battery requires
charging
5 red Internal battery is discharged.Starting not
possible, internal battery requires charging
6.2 Exhaustive discharge protection
To avoid a damaging exhaustive discharge of the internal bat-
tery, the ON period for the BAT 251 is restricted to 4 hours
in all operating modes. The voltage of the internal battery is
continuously monitored according to the operating mode.
The BAT 251 shuts down if a critical limit is violated.
6.� Charging the internal battery in the
BA� 2�1
The charger for the internal battery is built into the
BAT 251 .
1. Plug the mains plug on the power cable (Fig. 1,
Pos. 4) for the BAT 251 into a mains socket.
2. The internal battery in the BAT 251 charges
 Yellow LED 1 lights up.
3. Charging is complete and charge conservation for
the internal BAT 251 battery is running.
"
The yellow LED 1 goes out and the green LED 2
lights up.
i
The BAT 251 can remain plugged in for an unlim-
ited period. In this way the battery is continuously
charged. The maximum charging time for a dis-
charged battery is approximately 14 hours. If the
mains voltage is low, the charging time for the inter-
nal battery will be extended.
Robert Bosch GmbH