Do the batteries in a high end Unity Quantum drain when the CPU is powered up?
What are battery lifetimes when CPU is powered up?
There are three batteries involved in keeping the application code, application current data and the TOD clock active when the CPU is powered off.
These batteries are not rechargeable so there is a very minor drain while the CPU is powered up.
If the PLC is powered up all year long except during one month of maintenance, this is considered 92% power up. At 92% power up, the minimum life is specified at 10.4 years. and 27.1 typical running at 60 degrees C.
Please refer to the Quantum Hardware Reference Manual for full detailed information concerning battery life.