I've got Verizon FiOS fiber optics in our building but their ONT (optical network terminal) is installed in an unheated garage. Their device comes with a weak battery backup unit that doesn't supply enough runtime. The garage generally stays above freezing but there have been a few occasions where it has dipped into the 20's for a few days.
I know the Smart-UPS units are rated for 32 - 104 °F but I'm curious if anyone has any experience running them at or slightly below the low end of that range. Do they shut off at 32 or is this 32 degree figure a conservative number where the performance of the unit degrades?
As far as APC's recommendations go, the "Usage Temperature" is the range at which the unit will function without risk to its internal electronics or the protected load. Additionally, this temperature range is meant to ensure an acceptable battery lifespan, as well as acceptable performance over that lifespan.