User manual

Document No. 6-0101 Rev. D Page 20 of 38
Note that the above formula is approximate and the full charge state should be verified using the
criteria given above (current drops below 0.5% of rated capacity). If the recharge does not
return 102% to 110% of the discharged capacity, the battery’s state of charge will gradually
“walk down” as it is cycled leading to premature failure. Therefore, it is important to verify that
the battery is not being undercharged.
For repetitive deep cycling applications (deeper than 50% DOD), chargers should have an
output current of at least 0.2C (20 Amps for a 100 Ah battery). If the output current is less than
this value, the cycle life of the battery may be negatively affected. If a charger with at least 0.2C
output is not practical, an alternative charge profile using a low rate constant current stage at
the end of the absorption stage will normally improve the cycle life. The constant current stage
should be at 0.02C (2 Amps for a 100Ah battery) for no more than one hour.
Some types of battery chargers allow the user to input the Peukert constant to obtain an
optimum charging profile. For Lifeline® batteries, the recommended value of the Peukert
constant is n = 1.12.
5.5 Conditioning
Conditioning should only be done when the battery is showing symptoms of capacity loss due to
extended time in a partial or low state of charge condition. This could be caused, for example,
by low charging voltage for an extended number of charge cycles, or by repeatedly charging to
only 90% state of charge.
NOTE: Some chargers use the term Equalizing Charge instead of Conditioning Charge. An
Equalizing Charge is generally applied to flooded lead acid batteries that are susceptible to acid
stratification. However, an Equalizing Charge may be used to provide a Conditioning Charge for
Lifeline® batteries as described below.
To apply a conditioning charge, first go through the normal charge cycle to bring the battery to
full charge. The conditioning charge should then be applied by charging for 8 hours. At 77°F
(25°C), the conditioning voltage should be set at 2.58 VPC (15.5 volts for a 12 volt battery). The
conditioning voltage at other temperatures is shown in Table 5-2. By using the temperature-
compensated conditioning voltage, batteries that are not in controlled temperature environments
may be conditioned without bringing them to room temperature. If temperature compensation is
not available, it is best to bring the battery as close to room temperature as possible before
applying the conditioning charge.
Table 5-2. Conditioning Voltage at Different Temperatures for a 12 Volt Battery*
Temperature °F
Conditioning
Voltage
Temperature °F
Conditioning
Voltage
-40
18.05
70
15.58
-30
17.75
77
15.48
-20
17.47
80
15.44
-10
17.20
90
15.32
0
16.95
100
15.21
10
16.71
110
15.12
20
16.48
120
15.04
30
16.27
130
14.98
40
16.07
140
14.93
50
15.89
150
14.90
60
15.73
160
14.88
* For a 6 volt battery, divide the voltage by 2. For a 2 volt battery, divide the voltage by 6.