Operator`s manual

59 5 Maintenance
5.1 Testing the Battery Backup Time
This test measures how long the batteries can provide backup power by having them power the
loads until they are discharged.
Tips:
• This test should be done once a year when the batteries are new. When the batteries are
three years old or older, it should be done once every six months.
• This test should be done when new loads are connected to the unit.
• The unit should have been in Line Present mode for 24 hours before starting this test so
the batteries are fully charged.
• Do a self test (Section 3.3) first. If it passes then do this test. If it doesn’t find out why
before proceeding.
• For reference, compare your measured time to the times listed in Section 5.6, “Battery
Run Times.” Because of various factors, your time may not match the times listed.
Procedure:
1
Switch off the Input circuit breaker.
The display panel’s Line Failure LED turns on showing the unit is
operating on backup battery power.
Record this start time.
2
The Low Battery Warning LED turns on.
Record this time.
3
The run time is the time between
1
and
2
.
4
Switch on the Input circuit breaker.
The unit runs on line power and starts charging the batteries.
Battery Backup Time Test Finished