Comdial G0408 Manual page 87

IMI66–107
During AC operation, the common equipment provides recharging current to maintain the
voltage potential of the external battery assembly at an operational level. The charging circuit
may not provide an adequate charge if an installed battery assembly has a current rating of
greater than 40 ampere-hours. You should measure the battery assembly voltage every three
months.
For proper backup capabilities, make sure the batteries meet the following specifications:
• With a fully-charged battery assembly disconnected from the common equipment, the
measured voltage must be greater than 12 VDC but should not exceed 13.5 VDC.
• With a fully-charged battery assembly connected to the common equipment, the measured
voltage should be less than 13.8 VDC. If the voltage measures higher than this limit,
contact your Comdial Technical Services representative.
• The open output of the common equipment battery charger connection measures 13.6–13.8
VDC. If the charging voltage measures higher or lower than this range, contact you
Comdial Technical Services representative
• An optional external battery assembly requires approximately 10 hours to completely
re-charge to full potential after it has been completely discharged and, in some cases, when
initially installed.
Figure 2–27: Connecting The Battery Back Up Assembly
Digital Telephone System
Installing The DSU 2 – 57