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When in winter mode, maintenance charging continues to be performed as usual. If the PowerRouter is
configured to perform maintenance charging once every three weeks, the battery will be fully recharged at
this interval. Even in winter mode, the battery is always available to provide backup power. When needed, the
battery is reactivated and then used to provide the backup power.
Battery charging methods
The PowerRouter can be configured to use either of the two available battery charging methods: fixed float
voltage or 3-state adaptive charging. The 3-state adaptive charging method is best suited for rapid battery
charging. This is the best configuration for a self-use system.
3-state adaptive charging
In the first stage the battery is charged at a high current
until it reaches 70-80% of the battery’s charge capacity
(blue line). The battery voltage (green) rises to the bulk
voltage during this stage. In the second stage, the
voltage applied to the battery remains constant, while
the charging current gradually drops to a quarter of
the bulk current. This stage ends once the battery has
reached approximately 85-90% of its capacity. In stage
3 the charging voltage is reduced to the trickle-charge
voltage and the battery is gradually charged to 100%.
This final stage lasts the longest.
Battery discharge limiter
To protect the battery against excessive discharge
current, it is possible to limit the discharge power
during self-use. This limit value can be configured in
the Software Installation Tool. The value that should
be set depends on how the batteries are connected
(number of parallel branches). When using batteries
for which the battery supplier specifies a maximum
discharge rate of 100 A, for example, the limit value for
four 12V batteries connected in two parallel strings of
two should be (2x100Ax24V=) 4800W, but for two 12V
batteries connected in a single string (in series) the
limit value should be just (100Ax24V=) 2400W. When
the system is providing backup power, however, it
temporarily disables the limiter.
Figure 26: 3-state adaptive charging
Figure 27: Battery discharge limiter
12V
12V
12V
12V
100A
100A
20
0A
