Alpha Vision Tech MPS48-7M technical manual Battery Backup Mode, Charging Mode

5.0Operation

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.

5.4Charging Mode

Under normal conditions, a float 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.

Battery Capacity (%) vs. Temperature

	120
	100
(%)	80
Capacity
	60
Battery	40
	20
	0-40°F	-20°F	0°F	20°F	40°F	60°F	80°F	100°F
	(-40°C)	(-29°C)	(-18°C)	(-7°C)	(4°C)	(16°C)	(27°C)	(38°C)

Ambient Air Temperature	without heater mat
*This chart is an approximation of the effectiveness of a heater verse no heater.	with heater mat

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

021-511-B4-002, Rev. B 23