Parallel and serial use – Rockwell Automation 1606-XL240-UPSE Power Supply Reference Manual User Manual
Page 21
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.
Rockwell Automation Publication 1606-RM013A-EN-P — March 2014
21
Bulletin 1606 Switched Mode Power Supplies
Example for calculating the service life and the required replacement cycle:
Parameters for the example:
A 26Ah battery with a design life of 10-12 years is used.
The average ambient temperature is 30°C.
One buffer event consumes approx. 25% of the achievable buffer time.
One buffer event every two days
Calculation:
Ambient temperature influence:
According to Fig. 27-1 curve C, a 5
years service life can be expected for an ambient temperature of 30°C.
Number of discharging cycles: 5 years * 182 cycles = 910cycles in 5 years.
According to Fig. 27-2, curve C has to be used (only 25% of battery capacity is required). 910 cycles have only a
negligible influence in a battery degradation and can be ignored.
Result:
The battery shall be replaced after 5 years.
Please note that the battery degrading begins from the production date (check date code on the battery) which may
shorten the replacement intervals.
Fig. 27-1 Service life versus ambient
temperatures, typ. *)
Fig. 27-2 Cell capacity degradation vs. discharging
cycles *)
20°C
10
30°C
35°C
40°C 45°C
8
6
4
2
Ambient Temperature
25°C
1
3
5
7
9
Service Life in Years
Design Life
of Battery
A:
3-5 Years
B:
6-9 Years
C:
10-12 Years
A
B
C
0
120%
100%
40%
20%
Number of Discharging Cycles
200
60%
80%
Cell Capacity
Depth of
discharge
A:
100%
B:
50%
C:
30%
400
600
800
1000 1200
A
B
C
*)
datasheet figures from battery manufacturer
27.2. Parallel and Serial Use
Do not use the DC-UPS in parallel to increase the output power. However, two units of the DC UPS can be paralleled
for 1+1 redundancy to gain higher system reliability.
Do not use batteries in parallel, since the battery quality test might create an error message.
Do not connect two or more units in series for higher output voltages.
Do not connect two or more units in a row to get longer hold-up times.