[CentOS] Back to apcupsd
John R Pierce
pierce at hogranch.com
Wed Mar 3 01:06:50 UTC 2010
m.roth at 5-cent.us wrote:
> ...that while the nominal voltage for the APC
> SmartUPS 3000 is 48V, the new batteries are showing 55.4V.
lead acid batteries are 2.1-2.15V per cell when fully charged, and the
trickle charging float voltage is more like 2.3V per cell. 2.3 * 6
cells/battery * 4 batteries == 55 V
to read the batteries charge state, you would need to disconnect them
from the charger(UPS) for about 4-6 hours before reading the voltage,
this lets the surface charge dissipate. After doing this, you should
see 12.6-12.8V per 12v battery, or 50.4 to 51.2V for your stack of 4 *
12V. All these voltages assume 68-72F battery temperature. 48V is
nearly totally discharged
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