Well, the battery in my SU1000NET ups is starting to go. I can get one off of APC's website for $128, I was kinda hoping to get it for cheaper.

I have an APC XS 1500VA unit that just finally failed on me (batteries crapping out). It's been quite useful, but power here has been less-than-good, mostly due to me tripping out a breaker ...

APC conveniently links, direct from the BE550G product page, to a company-branded replacement battery, the APCRBC110, which sells for $69.99. Yes, you’ve done your arithmetic right…that’s only $30 ...