5
Accidental deep discharging
For optimum operation the minimum voltage of the system should
be related to the duty as follows:
Duty
Minimum end voltage
5 min
≤
t
≤
1h
1.65V
1h
≤
t
≤
5h
1.70V
5h
≤
t
≤
8h
1.75V
8h
≤
t
≤
20h
1.80V
In order to protect the battery it is advisable to have system
monitoring and low voltage cut-out.
Deep discharge will produce a premature deterioration of the
battery and a noticeable reduction in the life expectancy of the
battery.
The effect of temperature
- on capacity
Correction factors for capacity, according to the temperature, are
as follows:
- on life
Operation of valve regulated batteries at temperatures higher than
20°C will reduce life expectancy. Life is reduced by 50% for every
10°C rise in temperature.
Maintenance/Checks
PowerSafe VX are maintenance free, sealed, lead acid batteries
and need no water addition.
The containers and lids shall be kept dry and free from dust.
Cleaning must be carried out with a damp cotton cloth only. Check
monthly that total voltage at battery terminals is (N x 2.28 V) for a
temperature at 20°C. (N = the number of cells in the battery). Take
annual readings of the voltages of cells making up the battery.
Keep a logbook to record values, power outages, discharge tests,
etc.
An autonomy test is recommended once a year.
Technical data when charging with a constant voltage
If the charger does not permit an adjustment of the float voltage in
relation to the temperature, it is possible to set a float voltage
value and a recharging voltage value according to the
temperature ranges indicated in the table below:
Temperature
Float Voltage
Recharging Voltage
0°C to 10°C
2.34Vpc
2.45Vpc
10°C to 20°C
2.31Vpc
2.40Vpc
20°C to 30°C
2.28Vpc
2.35Vpc
30°C to 40°C
2.25Vpc
2.30Vpc
40°C to 50°C
2.22Vpc
2.25Vpc
Discharge
0°C
5°C
10°C
15°C
20°C
25°C
30°C
35°C
40°C
45°C
50°C
Time
5 mins to
0.80
0.86
0.91
0.96
1
1.04
1.06
1.09
1.1
1.12
1.13
59 mins
1h to 24h
0.86
0.90
0.94
0.97
1
1.03
1.05
1.06
1.07
1.08
1.09
Publication No: EN-VX-IOM-001 February 03
www.enersysinc.com
