User`s manual

Battery life and replacement procedure Maintenance and inspection
MELSEC System Q, Hardware 10 – 7
● Q02(H)-, Q06H-, Q12H- or Q25HCPU (first digits of serial No. is "05011..." or later), Process
CPU (QPHCPU) and Redundant CPU (QPRHCPU)

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 %.

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.
CPU
Power-on
time ratio

Battery life (Q6BAT)
Guaranteed value

Actual service value

After SM52 turned on

Q02CPU 0 % 30000 hours
(3.42 years)
43800 hours
(5 years)
120 hours (5 days)
30 % 42887 hours
(4.89 years)
50 % 43800 hours
(5 years)
70 %
100 %
Q02HCPU
Q06HCPU
0 % 2341 hours
(0.26 years)
18364 hours
(2.09 years)
120 hours (5 days)
30 % 3344 hours
(0.38 years)
26234 hours
(2.99 years)
50 % 4682 hours
(0.53 years)
36728 hours
(4.19 years)
70 % 7803 hours
(0.89 years)
43800 hours
(5 years)
100 % 43800 hours
(5 years)
Q02PHCPU
Q06PHCPU
0 % 1897 hours
(0.21 years)
14229 hours
(1.62 years)
96 hours (4 days)
30 % 2710 hours
(0.30 years)
20327 hours
(2.32 years)
50 % 3794 hours
(0.43 years)
28458 hours
(3.25 years)
70 % 6323 hours
(0.72 years)
43800 hours
(5 years)
100 % 43800 hours
(5 years)
Q12HCPU
Q25HCPU
Q12PHCPU
Q25PHCPU
Q12PRHCPU
Q25PRHCPU
0 % 1260 hours
(0.14 years)
7755 hours
(0.88 years)
48 hours (2 days)
30 % 1800 hours
(0.20 years)
11079 hours
(1.26 years)
50 % 2520 hours
(0.28 years)
15510 hours
(1.77 years)
70 % 4200 hours
(0.47 years)
28850 hours
(2.95 years)
100 % 43800 hours
(5 years)
43800 hours
(5 years)
Tab. 10-8: Battery (Q6BAT) lives of High performance model QCPU (first digits of serial No. is
"05011..." or later), Process CPU and Redundant CPU