hello all 

i have a little question, how long stands 6ES7971-0BA00 battery 

or in another words how often it must be replaced?

Hello,

You should change the backup battery once a year.

Thanks you

Hi,

as already mentionied, the backup battery should be replaced after one year.

You can also use this FAQ as a basis.

When should you replace the back-up battery on your S7 300/400 controller?

regards

sancruz

tigranes-97

hello all 

i have a little question, how long stands 6ES7971-0BA00 battery 

or in another words how often it must be replaced?

Ayman Elotaify

Hello,

The backup time is calculated from the capacity of the backup battery or batteries used and the backup current in the subrack. The capacity of the backup batteries is specified in the technical data of the power supply units concerned. See the technical data of the CPUs concerned for the typical and maximum CPU backup current. Since the backup battery is also loaded through the regular depassivation at Power On, you should base your backup time calculation on only 63% of the rated battery capacity and not 100%.

How great is the power requirement (from the backup battery) of the modules to be backed up at "Power Off" and what is the relationship between the backup current and the length of the backup time?

For sure the above explanation assumes that you are using original batteries. And that you followed depassivation procedure.