Charging, Discharging - Zumtobel ONLITE central CPS K Installation Instructions Manual

C.5

Charging, discharging

C.5.1 Charging
A charger with IU-charging characteristics should be used. Depending on the type of system
charging can be done in the following modes of operation:
• Continuous battery power supply and buffer mode
In this case the system, the DC-source and the battery are permanently in parallel mode.
The charging voltage is same as the battery voltage and as the system voltage.
In continuous battery power supply mode the DC-source is always capable of supplying
the maximum power for the system as well as for the battery charging. The battery only
supplies the power, if the DC-source fails. The charging voltage setting is 2.3 V DC / cell at
20 °C multiplied by the number of cells (+/- 1 %), with measurement taken at the end poles
of the battery.
In buffer mode the DC-source is not capable of always supplying the maximum system
power. which is sometimes higher than the power supply possible from the DC-source.
During these periods the battery supplies the energy. As the battery is not fully charged
permanently, the charging voltage has to be set user related to 2.3 – 2.4 V DC / cell.
• Switch mode
In this mode the battery is switched of from the system when charged. The max. charging
voltage of the battery is 2.4 V DC / cell (boost charge). Charging must be monitored.
Should at this constant charging voltage the charge current fall to 0.5 A / 100 Ah then the
float charge mode must be activated.
• Float charge mode
Equipment with IU charging characteristic should be used and set in such a way that the
voltage is 2.3 V DC / cell (+/- 1 %) at 20 °C. Should the battery temperature permanently
be higher or lower, the charging voltage has to be adjusted accordingly:
Charging voltage
20 °C)
Charging voltage
20 °C)
Examples:
Temperature predominantly around 15 °C, charge voltage = 2.3 V DC / cell + 0.015 V DC /
cell = 2.315 V DC / cell.
Temperature predominantly around 30° C, charge voltage = 2.3 V DC / cell –
0.030 V DC / cell = 2.270 V DC / cell.
Charging currents
With float charge mode the charging currents are generally not restricted. With boost charge
mode 20-30 A per 100 Ah nominal capacity should not be exceeded.
Ripple current
During recharging up to 2.4 V DC / cell in the operation modes continuous battery power
supply and buffer mode an effective AC-current of up to 20 A per 100 Ah nominal capacity is
acceptable. After recharging and during float charge mode the ripple current must not exceed
5 A per 100 Ah of nominal capacity.
= 2,3 V DC / cell - 0,005 V * ∆T (∆T= Temperature difference to
(> 20 °C)
= 2,3 V DC / cell + 0,005 V *∆T(∆T = Temperature difference to
(< 20 °C)
33