Bosch BAT 645 User Manual

i The battery need not be disconnected from the
vehicle electrical system during charging.
i If the voltage of the 24V battery is less than 17V,
each of the two series-connected 12V batteries must
be charged separately. Below 17V, the BAT 645 only
detects a 12V battery and charging would therefore
also only be performed for a 12V battery.
1. Connect the BAT 645 to the mains voltage system
via the power supply cable.
2. Connect the red charging clip to the battery
positive terminal (+).
3. Connect the black charging clip to the battery
negative terminal (–).
4. Switch on the BAT 645 by way of the on/off switch
(fig.1, item1).
 The red LED (fig.1, item7) lights up.
 The battery voltage is displayed (for four seconds)
then the "Mode" menu appears.
i The "Mode" menu is displayed (only with battery
connected).
5. Select "Charging mode".
6. Press
.
 The "Battery type" menu is displayed.
7. Select battery type.
Lead-acid battery:
UNI = universal characteristic for lead acid batteries
WET = liquid electrolyte battery (H
2
SO
4
)
AGM = AGM batteries
GEL = gel battery (electrolyte as gel)
EFB = EFB batteries
Lithium-ion battery:
LFP = LiFePO
4
batteries with BMS
8. Press
.
 The "Capacity" menu is displayed.
9. Select the capacity of the connected battery with
or .
10. Press
.
 The green LED flashes rapidly (fig. 1, item 8).
 Battery is charged after detection of its minimum
voltage.
Minimum voltage at 12V 24V
Lead-acid battery 3V 17V
Lithium-ion battery 9V 18V
Fig. 4: Standard charging
1 Charging progress (see charging characteristic fig. 3)
2 Current battery charge
3 Charging current supplied so far
4 Information on mode, battery type, length of charging cable,
battery voltage and battery capacity
i For exhausted batteries, the BAT 645 initially
employs gentle charging. The charging current
level is governed by the battery capacity setting.
The message "
Gentle charging" appears on
the display and the green and yellow LED flash at
1second intervals.
11. Charging mode is stopped with
.
 The green LED is off.
 The "Mode" menu is displayed.
i If charging is interrupted, the process must be re-
started.
12. Switch off the BAT 645 on completion of charging.
13. Remove the charging clips from the battery.
i In the case of cyclical battery operation
(wheelchairs, sweepers, ...), at least every 3rd
charging process should take the form of full
charging to maintain the battery capacity as long
as possible.
Operation | BAT 645 | 19 | en
1 689 989 233 2022-01-24| Robert Bosch GmbH

Bosch BAT 645 Specifications

General

Brand	Bosch
Model	BAT 645
Category	Battery Charger
Language	English