Johnny B Good wrote:

JOOI, What did you reset the charging voltage to on that APC SmartUPS?
Presumably it would have originally been set to 27.6v. Did you throttle
it all the way back to 27.0v?

I knocked mine down one click in the PROG mode to 54.05V according to
multimeter, and the internal data log agrees with that, however this is
constant regardless of temperature.

Most APC UPSes arrive from the factory with CSB (now Hitachi) batteries,
the datasheet for NP17-12 specifies all their characteristics at 25°C,
with a nominal charge voltage of 2.25 to 2.35V per cell, mine sits in a
cupboard where the UPS has an external temperature probe and measures
the temperature outside the case as 19°C and inside the case as 31°C.

Technically, I think the voltage ought to be dropped by 3mV per degree
above 25°C, and given that mine seems to sit between 31 and 34°C maybe
I'll knock it down another couple of clicks.

BTW, I've never seen APC batteries so badly cooked as that.

Did you see my photo? Quite a hump, though not from my own UPS I hasten
to add, currently using Tayna/Powerline batteries which seem to be doing
fine after 2 years.

I've long since retired the SmartUPS700 simply because of its
unconscionably high maintenance consumption of 20W (virtually none of
which goes into keeping the battery pack charged).

Yes, they are on the inefficient side ... but I've had a couple of power
cuts in recent months and the smug feeling when you see that every other
WiFi signal in the street has gone off is worth it :-)