Alpha Technologies FLEXNET POWER MPS48-7M - Manual (Page 23)

23 021-511-B4-002, Rev. B
5.0 Operation
5.3 Battery Backup Mode
In the event of an AC power outage, the MPS48-7M switches to battery backup mode to
power the load. The green status LED begins to blink, indicating the load is being powered
from the battery string. The MPS48-7M runs in battery backup mode until AC power is
restored, or until the battery string reach a low-voltage shutdown level of 42V. On resumption
of AC power, the MPS48-7M 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. In the
event of line failure, battery charging resumes automatically 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 support. Charging ceases until primary
power is restored.
• Additional power is required by the load, in which case power is diverted from the battery
charger and sent to the load. When demand for additional power ceases, normal battery
charging resumes.
Fig. 5-2, Battery Capacity Versus Temperature
Runtime (hours) vs Temperature Typical Recharge time vs Load
Load -40°C 0°C 25°C 40°C
20Watts 12.5 13.4 16.0 20 13 hr
40Watts 6.0 6.3 7.6 10 25 hr
50Watts 3.3 4.1 5.7 7.2 50 hr
Table 5-2, Battery Runtime and Recharge Times
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
*This chart is an approximation of the effectiveness of a heater verse no heater.