Batteries are mounted side-to-side or top-to-top and held together with
(effectively) "thick tape".
Yep, mine has the top-to-top arrangement with a little wiring block in-
between and the "thick tape" to hold it all together.
The larger capacity (2000+ VA) units tend to move up to 48V packs
for increased efficiency. And, the packs tend to be genuine entities
(not just batteries taped together but actual "enclosed cartridges")
Part of this is due to the increased weight of a set of four, LARGER
batteries as a replaceable unit.
It's a shame UPS's haven't switched to lithium batteries. They're smaller,
lighter weight, and they hold their charge longer. My power tools all use
20V lithium battery packs, and my string trimmer and leaf blower use 56V
lithium battery packs. Laptops and electric cars use lithium batteries too.
The only downside is that potential of catching fire.
A better solution is a better charger.
My previous replacement batteries wouldn't hold a charge from the day I
installed them. They seemed to charge up normally and the control panel
said I would get 70 minutes of run time. Unfortunately, when the power went
out the batteries drained very quickly and the UPS shut off after just 5
The new batteries are working like they're supposed to. I get at least 70
minutes with them.