Victron energy BlueSolar MPPT 50 Anleitung Seite 7

24V battery and mono- or polycristalline panels
● Minimum number of cells in series: 72
(2x 12V panel in series or 1x 24V panel).
● Maximum: 108 cells (3x 12V panel in series).
Remark: at low temperature the open circuit voltage of a 108
cell solar array may exceed 75 V, depending on local conditions
and cell specifications. In that case the number of cells in series
must be reduced.
3.3 Cable connection sequence (see figure 1)
First: connect the battery.
Second: connect the solar array (when connected with reverse
polarity, the controller will heat up but will not charge the
battery).
3.4 More about automatic battery voltage recognition
3.4.1 First time system voltage recognition
When the battery has been connected and the voltage on the
PV input has increased to more than 7 V, the controller
determines system voltage as follows:
Battery voltage below 17,5 V: 12 V system (factory setting).
Battery voltage above 17,5 V: 24 V system.
3.4.2 Products with software verion V 1.11 or lower:
As long as the voltage on the PV input exceeds 7 V, the controller
will not change the set system voltage, whatever happens with
battery voltage.
When PV voltage drops below 7 V, the controller will reset and again
determine system voltage when PV voltage increases to more than
7 V. Therefore, if a 24 V battery has been discharged to less than
17,5 V during the night, the controller will set to 12 V in the morning.
3.4.3 Products with software version V 1.12 or higher:
The set system voltage is stored in non volatile memory.
A reset to 12 V occurs only when output voltage decreases to less
than 2 V and voltage on the PV input exceeds 7 V. This may occur if
the battery has been disconnected before PV voltage starts to rise in
the early morning. When the battery is reconnected later during the
day, voltage has to exceed 17,5 V for 10 seconds before system
voltage is set to 24 V.
If the controller has to be reset from 24 V to 12 V we recommend to
short circuit the output and apply a voltage exceeding 7 V on the input
(for example with a small power supply, a solar panel or a battery)
during a few seconds.
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