Rockwell Automation 1606-XL240-UPSE Power Supply Reference Manual - Manual (Page 8)

All parameters are specified at an input voltage of 24V, 10A output load, 25°C ambient and after a 5 minutes run-in time unless noted otherwise.
It is assumed that the input power source can deliver a sufficient output current.
8 Rockwell Automation Publication 1606-RM013A-EN-P — March 2014
Bulletin 1606 Switched Mode Power Supplies
9. Buffer Time
The buffer time depends on the capacity and performance of the battery as well as the load current. The diagram
below shows the typical buffer times of the standard battery modules.
Buffer time with 26Ah battery (1606-XLSBATASSY2)
min. 99’30’’ At 5A output current *)
min. 39’ At 10A output current *)
typ. 130’ At 5A output current, see Fig. 9-1 **)
typ. 55’ At 10A output current, see Fig. 9-1 **)
Buffer time with 100Ah battery min. 62h 20’ At 0.5A output current *)
min. 3h At 10A output current *)
typ. 82h 20’ At 0.5A output current, see Fig. 9-1 **)
typ. 4h At 10A output current, see Fig. 9-1 **)
*) Minimum value includes 20% aging of the battery and a cable length of 1.5m with a cross section of 2.5mm 2 between the
battery and the DC-UPS and requires a fully charged (min. 24h) battery.
**) Typical value includes 10% aging of the battery and a cable length of 0.3m with a cross section of 2.5mm 2 between the battery
and the DC-UPS and requires a fully charged (min. 24h) battery.
Fig. 9-1 Buffer time vs. output current with a 65Ah and a 100Ah battery
Buffer Current
0
40 50
0.5
1.0
1.5
2A
70 80 60 90h 30
A
B
A: 65Ah Battery
B: 100Ah Battery
Buffer Time (Hours)
30h
Buffer Current
0
5
2
4
6
8
10A
10 15 20 25
Buffer Time (Hours)
A
B
A: 65Ah Battery
B: 100Ah Battery
5
The battery capacity is usually specified in amp-hours (Ah) for a 20h discharging event. The battery discharge is non-
linear (due to the battery chemistry). The higher the discharging current, the lower the appropriate battery capacity.
The magnitude of the reduction depends on the discharging current as well as on the type of battery. High current
battery types can have up to 50% longer buffer times compared to regular batteries when batteries are discharged
in less than one hour.
High discharging currents do not necessarily mean high power losses as the appropriate battery capacity is reduced
with such currents. When the battery begins to recharge after a discharging event, the process is completed much
faster since only the energy removed from the battery needs to be “refilled.”
For this reason, the buffer time cannot be calculated using the Ah capacity value. The equation “I x t” = capacity in
Ah generally leads to incorrect results when the discharging current is higher than C20 (discharging current for 20h).