I use a online UPS with 2 pairs of 6 batterys in series as a poor mans power wall. Had the batterys going for 2 years now and no issue.
I mainly got a online UPS tho so I could tie my solar pannels into the battery pack since its always charging and then inverting the power back to AC.
So the charger turns its self off for a few hours when there is a good ammount of sun and the UPS is wired up to 80% of the house so all the important stuff still works when there is a power cut which is common where I live.
SLI Voodoo 2 - > GeForce4 MX 420 -> GF 6600GT -> GF 6800GT -> GF 8800Ultra -> AMD 4870 -> AMD 4890 -> CF AMD 5820 -> CF AMD 6850 -> CF AMD 7970 -> SLI GF 680 -> SLI GF 780 -> CF AMD 290X -> GF 980ti -> SLI GF 980ti -> GF 1080ti -> SLI GF 1080ti -> <- RTX 2080ti (DOA/Refunded)