User`s manual
MPS Doc: M359_USER_MANUAL REV J Oct 23, 2014 Page 21 of 30
6. Maintaining the M359
6.1. Battery Test
To test the Battery, press momentarily on the BATT TEST Push-button (26).
Battery Test may be invoked only when all the following conditions are true: the UPS is
running on AC input power, the Battery Charge level is above 85% and the load level is
above 35%. If Battery Test is denied due to low charge level ( when the BATT TEST Push-
button is pressed) the BATT CHARGE Level Bar Graph will blink once.
When the Battery Test starts, the BATT TEST PASS green LED (27) will blink for about 3
seconds (indicating that Battery Test is running). After about 3 seconds, either the BATT
TEST FAIL red LED (25) will turn on (and latch), indicating a bad battery, or the BATT TEST
PASS green LED (27) will turn on and remain on for about 20 seconds, indicating that the
Battery has successfully passed the test. The Battery Test may be repeated only after at
least 20 seconds have elapsed since the last test.
6.2. Battery Service Life
The gel lead-acid, sealed and maintenance-free battery used in the M359 is of the highest
quality. Nevertheless, it is a Limited Life Item, and its life expectancy depends upon its
operating and storage conditions.
The three most important factors that determine the life of the battery are:
Temperature
Storage Conditions
Charge-Discharge Cycles
6.2.1. Temperature
The battery used in the M359 is sealed and does not “dry up” or lose gasses, but its end
of service life is brought about by the gradual corrosion of the electrodes. This process
is highly accelerated by high operating temperatures. Every 10°C rise above 20°C will
reduce the battery service life by half.
6.2.2. Battery Storage
When lead-acid batteries are stored for extended periods of time, lead sulfate is formed
on the negative plates and insulates them. The sulfating rate depends on the ambient
temperature and the charge level of the battery. High temperature and low charge level
accelerate the sulfating and reduce the battery life. In order to protect your battery from
damage during storage:
If practical, store in a cool place (may be stored separately from the UPS).
Never store a discharged battery. Storing a discharged battery will damage it.
Make sure that the battery is fully charged periodically (every 6 months at 27C
(81F) or lower, every 3 months if higher, but not above 38C (100F). Charging
may be accomplished by operating the UPS for six hours (can be in the Stand-
by Mode).