Miti,
Did you replace your battery while powered on, or did you back up the ram, change battery, and then restore ram?
I backed up my ram, but haven't changed out the battery yet. Guess I'm chicken. LOL 
I replaced the batteries on two meters with the power on, after I saved the RAM using both, Python and Windows applications. I plugged the soldering station into a UPS disconnected from AC. Make sure that you also disconnect any other load from the UPS otherwise you may have grounding through that load. For example if a PC is connected to the UPS but the monitor is plugged into the wall, you're grounded.
I didn't need to restore after, all went well. I used Kapton tape to isolate everything around the battery terminals on the PCB, only the "operation" site was exposed like you see in surgeries.
The funny thing is that less than an hour after the "surgery" we had a power outage for about a minute.

Man that was close!
Before I had the guts to do it, I tried the backup/restore on another meter from work that is not used anymore, the type with transformers, mine are newer, with opto couplers and the C application works.
I modified the file and I've got an "Uncalibrated", then I restored it and I've got "Self test OK". One little detail though, when you copy/paste the data from the application window into a text file, place the cursor one row below the last row of data. Do the same when you restore the data, basically copy the last new line or carriage return, otherwise it doesn't work.
I've got the batteries from Sayal (in Toronto) STOCK No. BCC-4194, 3.6V.
I'm not sure if they needed replacement though, both old Panasonic batteries measured over 3.3V and the date code seem to be 2003 . Anyway, it's done,they should be good for another 10 -15 years at least.
The next project, replacing my Tek. 2445B battery backed calibration RAM with F-RAM.