Storage time of 6ES7-971-0BA0 backup battery

There is simply no available data - Siemens don't give anything away:

The data sheet provides even less information:

However the battery is fairly substantial and appears to work well in a S7-400,
So a 10 year life span would not seem unreasonable.

However I've never seen any reason to question battery life in any PLC related backup scenario;
If the PLC is powered it would give a 'low battery alarm' at the right time.
If not powered for several years I would expect a dowloaded application program with supporting hardware to be available. Battery support would be, more or less it's shelf minus say 1 year which gives us 9 years.

If you have a PLC unpowered for such a long time. I wouldn't expect it to work anyway. Only once have I gone through 2 racks checking all edge connector contacts on a stored PLC5. Battery and associated contacts were good and program retained.
Generally Only dry / non-rechargeable batteries are used for PLC battery backup;
and as indicated above - shelf and working life depends on environmental conditions.

I now recall way back in the late 70’s someone asked about a French PLC backup battery having a shelf life ‘probably less than 18months’ if stored in an unheated shed located near the Russian/outer Mongolian border where winter temperatures typically -25Deg C or lower.
Hello All

I join this thread with the answer on this question

See following calculations depending on backup battery capacity...

Looking to hear back from you soon,

Any time!


View attachment 1328

I did efforts and you just cliked on "like" ...
My post desserve more than a "like" ...I provided the exact answer on the original post

And now I will make less than I did ..thanks to THE people who have a behavior like this one ...pfff
" I provided the exact answer on the original post"......
Maybe ! I thought the results were poor so tried Siemens Forums:

The op hasn't stated CPU model - seems battery current consumption varies dramatically depending type.
You just have to read my ^post and depending on battery capacity you can calculate Storage time thats it ...