Rockwell Automation 1606-XLS240-UPS Power Supply Reference Manual - Manual (Page 8)

All parameters are specified at 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-RM036A-EN-P — April 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 battery module 1606-XLSBATASSY1 min. 19’12’’ At 5A output current *)
min. 5’42’’ At 10A output current *)
typ. 21’30’’ At 5A output current, see Fig. 9-1 **)
typ. 6’45’’ At 10A output current, see Fig. 9-1 **)
Buffer time with battery module 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 **)
*) 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 the battery modules 1606-XLSBATASSY1 and 1606-XLSBATASSY2
Buffer Current
5 15
2
4
6
8
10A
20 10 25 30 35 45 5 5 0 4 0 5 60 65 70 75 80 85
Buffer Time (Minutes)
1606-XLSBAT1 typ.
1606-XL
SBAT2
12V 7Ah battery
12V 26
A h batt
ery
120 150 210 240 300
Min.
180 270 90
1606-XLSBAT2 typ.
90
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 1 hour.
High discharging currents do not necessarily mean high power losses as the appropriable 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 which was taken out of the battery needs to be “replenished.”
For this reason, the buffer time cannot be calculated using the Ah capacity value. The equation “l x t = capacity” in
Ah generally leads to incorrect results when the discharging current is higher than C20 (discharging current for 20h).
Study the battery datasheet and determine the expected buffer time by using the example on the next page.
1606-XLSBAT1 typ.