Dometic BUTTNER MT LB 40 Instructions De Montage page 15

PIN Designation
4 Temp 1
5 Temp 2
6 –
7 –
Battery charging function
A main charging cycle of the house battery is initiated in the following situations:
• After a standstill of the alternator
• After falling below the reset voltage
Fig.  on page 4
In all charging phases, almost the entire possible charger current is available for the additional supply of DC loads
without discharging the battery.
The charging characteristics for fully automated continuous operation without monitoring are referred to as IU0U
characteristics.
1, 2: Analysis phase (Recondition and pulse)
The battery is deeply discharged (> 10 %). The battery charge is analyzed with increasing charging current.
3, 4: I phase (Constant current phase – Bulk)
At the beginning of the charging process, the empty battery is constantly charged with half of the the maximum
charging current (50 %). The charging current increases to 100 % after 1 min. Deeply discharged lead batteries are
charged with reduced charging current until the battery voltage exceeds 12 V. The duration of the I phase depends
on the state of the battery, the load from the consumers and the state of charge. For safety reasons the I phase is ter-
minated after a maximum of 15 h (in case of battery cell defects or similar).
5: U1 phase (Constant voltage phase – Absorption)
The U1 phase starts when the battery is fully loaded. The charging current is reduced. During the U1 phase, the bat-
tery voltage is kept constant at a high level. The duration of the U1 phase depends on the battery type and the depth
of discharge.
6: Desulfation phase
A constant current will be delivered, allowing the battery voltage to rise independently to the maximum value. The
desulfation phase is not used for LiFePO4 batteries.
7: U2 phase (Trickle charging – Float)
The U2 phase serves to maintain the battery capacity (100 %). The U2 phase runs at lowered charging voltage and
variable current. If DC loads are connected, they are powered by the device. Only if the power required exceeds the
capacity of the device, this surplus power is provided by the battery. The battery then is discharged until the device
re-enters the I phase and charges the battery. The U2 phase is limited to between 24 and 48 h depending on the
battery type.
Description
Connection for temperature sensor (optional)
Not used
Remote charging status signal
MT LB EN
15