Alpha Technologies FlexNet MPS48-12M - Technical Manual - Manual (Page 26)

26 021-514-B2-001, Rev. A
5.0 Operation
5.3 Battery Backup Mode
In the event of an AC power outage, the MPS48-12M switches to battery backup mode and
the green status LED begins to blink. The MPS48-12M runs in battery backup mode until AC
power is restored, or until the battery string reaches a low-voltage shutdown level of 42V. On
resumption of AC power, the MPS48-12M recharges the batteries at a maximum current of
1.8A.
5.4 Charging Mode
Under normal conditions, a fl oat charge maintains the batteries at 100% capacity. If the unit
operates in battery backup mode, battery charging resumes when primary power is restored.
Charging continues until one of the following occurs:
• Battery has reached 100% of capacity.
• Another power failure occurs requiring battery backup.
• Additional power is required by the load, in which case power is diverted from the battery
charger to the load. When demand for additional power ceases, normal battery charging
resumes.
NOTE:
The MPS48-12M will not exceed a 56Vdc output.
0
20
40
60
80
100
120
-40°F
(-40°C) -20°F
(-29°C) 0°F
(-18°C) 20°F
(-7°C) 40°F
(4°C) 60°F
(16°C) 80°F
(27°C) 100°F
(38°C)
Ambient Air Temperature
B
a
tt
er
y
C
ap
aci
ty
(%
)
without heater mat
with heater mat
Battery Capacity (%) vs. Temperature
Fig. 5-2, Battery Capacity Versus Temperature
Typical Recharge Time vs Load @ 77ºF (25ºC)
Load Hours
0W 9
20W 12
40W 18
60W 35
Table 5-2, Battery Recharge Times