Dave Liquorice wrote:

Now that I've got at my APC Smart UPS 700 to stop it cooking
batteries it "just works". It did before but would kill a set of
batteries in 3 to 4 years. Charge rate far too high for the
temperature of the batteries.

I replaced the batteries in my SU2200 three years ago, and they've held
up since, I did check it wasn't overvolting them.

Looking at the UPS internal (43°C) and external (32°C) temperatures for
the last few weeks, I suspect it doesn't de-rate the charge voltage for
temperature as it's been locked at 54.05V

Yuasa seem to suggest decreasing float voltage by 3mV for every degree
above 20°C