Alpha Technologies AlphaCell HP - Manual (Page 20)

745-680-C5-002, Rev. A 20
To help identify batteries approaching end of life in an operating power system, test #1 should be performed at each
maintenance interval. For batteries not installed in an operating power system, test #2 or #3 may be performed. For
accuracy, tests must be performed on fully charged batteries.
A battery failing any of the following combined tests is defined as a faulty battery. The battery will be replaced under the
terms of the warranty if within the defined warranty period.
Evaluation Procedure 1
Conductance/Impedance Test – Measure the conductance of each battery. Any battery that possesses a conductance
that is 50% less than the initial reading taken at the point of install can be considered suspect of being below 70%
capacity and should be evaluated further. The battery temperature must be approximately the same each time this reading
is taken (see Table 1 below). Use temperature compensation feature when using Midtronics meter.
AND
Float Voltage Test – Measure the float voltage of each battery in the string that is on float charge. Any battery in the string
measured at 13.2 volts or less is a suspect battery and should be further evaluated with the steps below. Any battery
below 12.6 volts should be replaced. The 13.2 & 12.6 voltage values are based on a 77˚F (25˚C) temperature. Adjust the
voltage for higher or lower temperatures by 0.0168 Volts per battery per degree Fahrenheit. The higher the temperature
above 77˚ F (25˚C) the lower the voltage will have to be adjusted and vice-versa for temperature below 77˚F (25˚C). (i.e.:
at a temp of 89˚F (32˚C) would have a corresponding float voltage of 13.0 volts).
Evaluation Procedure 2
Conductance/Impedance Test – Measure the conductance of each battery. Any battery that possesses a conductance
that is 50% less than the initial reading taken at the point of install can be considered suspect of being below 70%
capacity and should be evaluated further. The battery temperature must be approximately the same each time this reading
is taken. Consult table 1 below for guidance. Use temperature compensation feature when using Midtronics meter.
AND
24 Hour Open Circuit Test – Measure the open circuit voltage of the suspected battery 24 hours after the battery has
come off of float charge. Care must be taken to ensure that the battery is at full state of charge when it is disconnected
from the power supply. The battery should exhibit a voltage about 12.60V. A battery below this voltage should be replaced.
A fully charged battery below 12.6 volts is below 70% capacity, but a battery above 12.6 volts is not necessarily above
70% in capacity. Batteries that have been sitting for extended periods should be recharged after 6 months or when they
reach 12.48 volts (75% capacity), which ever comes first depending on the storage temperature.
Evaluation Procedure 3
24 Hour Open Circuit Test – Measure the open circuit voltage of the suspected battery 24 hours after the battery has
come off of float charge. Care must be taken to ensure that the battery is at full state of charge when it is disconnected
from the power supply. The battery should exhibit a voltage about 12.60 volts. A battery below this voltage should be
replaced. A fully charged battery below 12.6 volts is below 70% capacity, but a battery above 12.6 volts is not necessarily
above 80% in capacity. Batteries that have been sitting for extended periods should be recharged after 6 months or when
they reach 12.48 volts (75% capacity), which ever comes first depending on the storage temperature.
AND
100A Load Test – Measure the voltage of each battery at the end of a 10 second 100-amp load test. Again, the
temperature must be equivalent to that of the original test performed at the point of installation. A significant drop in
voltage versus the previous test will indicate deterioration of the battery. A 12-volt battery that falls below 10.80 volts
should be considered faulty and should be replaced.
To maintain consistent test results, ensure the same Midtronics conductance tester is used for each test cycle.
NOTE:
3.4 Battery Evaluation procedures for AlphaCell™ HP
Midtronics Conductance
Models 3200/micro CELLTRON
3.5 HP 4.0 HP
Approximate Conductance Values (mhos)
Healthy Battery @ 77°F (25°C)
1400-1850 1700-2500
Suspect Battery @ 77°F (25°C) in mhos <680 <840
Table 1, Conductance values, healthy vs. suspect batteries