Float Operation - EnerSys PowerSafe mP Series Battery Safety, Installation, Storage, Operating And Maintenance Manual

17.2 Float Operation

In this type of operation, the battery and the critical load circuits are continuously connected
in parallel with a constant voltage charger. The charger should be capable of:
• charging the battery from the discharged condition while supplying the DC power to
the connected DC load
• providing the required constant float voltage
• providing voltage for equalizing the battery
If the batteries' ambient temperature is outside the range of 68°F (20°C) to 80°F (27°C),
it is highly recommended that the battery be charged with a temperature compensated
charger with adjustment as stated in Table 17.1. If a temperature compensated charger is
not used, manual adjustments must be made according to Table 17.1.
AVERAGE AMBIENT TEMPERATURE
˚F
25
35
45
55
65
77
85
95
105
115
125
Float voltage sustains the battery in a fully charged condition and makes it available to
assume the emergency power requirements in the event of an C power interruption or
charger failure.
Constant voltage output charging equipment is recommended. This type of charger, properly
adjusted to the recommended float voltages, and the following recommended surveillance
procedures will assist in obtaining consistent serviceability and optimum life.
Publication No. US-MP-OM-001
March 2017
TABLE 17.1
RECOMMENDED FLOAT VOLTAGE
˚C
-4
2
7
13
18
25
29
35
41
46
52
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VOLTS PER CELL
2.33
2.33
2.32
2.30
2.28
2.25
2.23
2.21
2.19
2.17
2.17
31