IMHO battery backup / UPS systems are a good source of batteries for home RE. They're kept charged except during outages and tend to be rotated out for new ones when they've still got about 2/3 of their rated lifetime left. Then they can last longer than rated in home service if you keep 'em properly charged and have enough of 'em so they don't discharge deep - which is easy if you're getting them in power-a-server-farm-for-a-half-hour lots at scrap prices. B-)
(If a company is paying the big bux to keep a critical load running or shutting it down gracefully in a power outage they're not going to let the batteries get near end-of-life and then have the UPS fail to do its job when needed. Providing management and the facilities department are on the ball, of course.)
(I'm trying to cut a deal at my day job for the next double-pallet of batteries they rotate out, in a year or two. The last batch caught me by surprise so I wasn't ready for it. B-b)