On Fri, 1 Oct 2004 22:02:00 -0400, "Isi"
wrote:

The APC Smart UPS 600VA (AP600) had dead batteries, and I replaced them with
new ones. After replacing the batteries, I tested the unit with a 100W load
(light bulb), and it switches to battery mode properly with cut AC. Once the
load is increased to 300W (halogen bulb again) it reports low battery, even
when the AC power is present. The unit properly switches to battery power on
AC loss, but low battery is still on. Once the load is decreased, the low
battery goes off instantly and it works normally. I checked the battery
voltage and I found 26V (2X13V) with 300W load (or no load) and AC power,
and 23.5V (2X11.75V) when operated on battery with cut AC and 300W load,
which seems OK. Is a recalibration required after replacing the batteries?

Are you sure that the meaning of the indication is 'weak battery'
exclusively ?
I could imagine a more general 'attention required' indicator,
which would be triggered by both 'weak battery' and 'execessive
load connected' situations.
Your opservations seem to support this.

(If it is a really smart UPS, it could sense that it probably
would not be able to start your 300 Watt halogen load :-)

--
Kind regards,
Gerard Bok