Backup battery systems aren't known to explode that I know of if they die the battery just needs replacing
This all assumes of course it's not some clone from aliexpress or some home made concoction
Otherwise the length of the cords are pretty much it
Never use an extension cord for a computer
If you do for the backup battery make sure it's the same gauge wire as on the unit otherwise don't use a extension cord for it either.
while i measure with my phone with an app that measures EMF radiation, i get some level of radiaton near up to 30cm far away from my ups-es and i was wondering if i should place the desktop unit more far away or not . Excuse my english please.