Alpha Technologies XM3-HP Series - Technical Manual - Manual (Page 99)

99 017-882-B0-001 Rev. C2 (10/2013)
4.0
Maintenance
4.4 Battery Maintenance, continued
4.4.4 Capacity
4.0 Maintenance, continued
The actual capacity is related to the utilization ratio of the active positive and negative materials
within the battery. The utilization ratio is influenced by the depth of discharge, the structure of the
battery, and the manufacturing technology. During normal usage, the factors that influence the
actual capacity are discharge rate, depth of discharge, end voltage, and temperature.
• The higher the discharge rate, the lower the available capacity.
• As batteries get colder, the available capacity is reduced (See Fig. 4-3). This is related to
the kinetics of the electrochemical reactions and the resistivity of the electrolyte.
Although the battery can be operated at temperatures below -4ºF (-20ºC), the capacity and ability
to discharge will be dramatically decreased. Similarly, temperatures approaching 122ºF (50ºC) will
increase electrolyte loss and corrosion of the plates, resulting in a shorter battery life.
NOTE:
Fig. 4-4, Available Capacity vs. Ambient Temperature
-40°F/
-40°C
-22°F/
-30°C
-4°F/
-20°C
14°F/
-10°C
32F/
0°C
50°F/
10°C
68°F/
20°C
86°F/
30°C
104°F/
40°C
20%
30%
50%
70%
90%
10%
80%
60%
100%
40%
0%
Percent Rated Capacity Available
Efficiency VS. Temperature
AlphaCell 3.5HP and 4.0HP
4.0HP
3.5HP
Typical Gel
4.4.5 Preparing for Maintenance
The battery system should be remotely monitored and physically inspected periodically. If the
battery system has an automatic monitoring system to gather the electrical and environmental
data, the remote checks should consist of evaluating the recorded data and visiting any site that
does not meet the specifications listed in the detailed procedures below.
You do not have to measure the electrolyte specific gravity or add water to the cells.
All batteries in the string should be numbered to facilitate recording and analysis of data unique
to each unit.
Notify anyone affected by the intended maintenance or troubleshooting activity. This should
include but not be limited to anyone responsible for the status monitoring equipment at the head-
end or NOC.