User`s manual

Battery life and replacement procedure Maintenance and inspection
MELSEC System Q, Hardware 10 – 9

The power-on time ratio indicates the ratio of programmable controller power-on time to one day (24 hours).
When the total power-on time is 12 hours and the total power-off time is 12 hours, the power-on time ratio is 50 %.

refer to Tab. 10-5

The guaranteed value represents a battery life at 70 °C, which is calculated based on the characteristic values of
manufacturer-supplied memories (SRAM) and on the assumption of storage within the ambient temperature
range of –25 °C to 75 °C (operating ambient temperature of 0 °C to 55 °C).

The actual service value (reference value) represents a battery life that is calculated based on the values meas-
ured at storage ambient temperature of 40 °C. This value is intended for reference only, as it varies with charac-
teristics of the memory.

In the following status, the backup time after power off is 3 minutes:
– The battery connector is disconnected.
– The lead wire of the battery is broken.
Q10UD(E)HCPU
Q13UD(E)HCPU
Q20UD(E)HCPU
Q26UD(E)HCPU
0 %
1
22600 hours
(2.58 years)
43800 hours
(5 years)
600 hours
(25 days)
30 % 32200 hours
(3.68 years)
50 % 43800 hours
(5 years)
70 %
100 %
0 %
2
4100 hours
(0.47 years)
26200 hours
(2.99 years)
384 hours
(16 days)
30 % 5800 hours
(0.66 years)
37400 hours
(4.27 years)
50 % 8200 hours
(0.94 years)
43800 hours
(5 years)
70 % 13600 hours
(1.55 years)
100 % 43800 hours
(5 years)
0 %
3
2300 hours
(0.26 years)
18600 hours
(2.12 years)
192 hours
(8 days)
30 % 3200 hours
(0.37 years)
26500 hours
(3.03 years)
50 % 4600 hours
(0.53 years)
37200 hours
(4.25 years)
70 % 7600 hours
(0.87 years)
43800 hours
(5 years)
100 % 43800 hours
(5 years)
0 %
4
1500 hours
(0.17 years)
13800 hours
(1.58 years)
144 hours
(6 days)
30 % 2100 hours
(0.24 years)
19700 hours
(2.25 years)
50 % 3000 hours
(0.34 years)
27600 hours
(3.15 years)
70 % 5000 hours
(0.57 years)
43800 hours
(5 years)
100 % 43800 hours
(5 years)
CPU
Power-on
time ratio

Battery con-
sumption
category

Battery life (Q6BAT)
Guaranteed value

Actual service val-
ue

After SM52
turned on

Tab. 10-9: Battery (Q6BAT) lives of the Universal model QCPU