Publication No. US-GPL-IS-AA June 2017
3
4.3 Discharge
It is strongly recommended that a low voltage cut-off be included in the
battery load circuit to protect the battery from over-discharges. The setting
for End of Discharge Voltage (EODV) is dependent on the rate of discharge,
as shown in the table below. For optimum battery life, we recommend that
the battery be disconnected from the load when the appropriate voltage is
reached and put back on charge as soon as possible after discharge.
Discharge rate in amps
Suggested minimum EODV
0.05C10 (C10/20)
10.50V
0.10C10 (C10/10)
10.20V
0.20C10 (C10/5)
10.02V
0.40C10 (C10/2.5)
9.90V
1C10
9.60V
2C10
9.30V
>5C10
9.00V
4.4 Charging
In a float or standby application the Constant Voltage (CV) charger should
be set at 13.5V to 13.8V at 77°F (25°C). For a cyclic application, the charge
voltage should be set between 14.4V and 15V at 77°F (25°C). In both cases,
the linearized temperature compensation factor is ±24mV per battery per °C
variation from 77°F (25°C). The higher the temperature the lower the charge
voltage should be and vice versa.
The graph below shows the temperature compensation factor for float and
cyclic applications. Equations representing the compensation curves are also
shown in this figure. Note that for both types of applications there is no limit
on the inrush current. We recommend the highest practical and economical
current.
For other possible techniques, refer to the Genesis
®
Battery Application
Manual.
4.5 State of Charge
The graph below shows the Open Circuit Voltage (OCV) and corresponding
State of Charge (SOC) for a Genesis battery. An OCV of 12.84V or more
indicates a battery at 100% SOC. The figure is accurate to within 20% of the
true SOC of the battery if the battery has not been charged OR discharged in
the 24 hours preceding the voltage measurement. The accuracy improves to
5% if the period of inactivity before the voltage measurement is five days.
Although efforts should be made to ensure that batteries are stored in
temperature-controlled environments, a freshening charge should be applied
once every twenty-four (24) months or when the OCV reading drops to 12V,
whichever comes first. As shown in the graph, 12V corresponds to a 35% SOC.
The battery may be permanently damaged if the OCV is allowed to drop below
11.90V.
4.6 Recovering Over-Discharged Batteries
There may be instances when a Genesis battery is over-discharged to the point
where a standard charger is unable to fully recharge the battery. In such cases,
the following procedure may help recover the affected battery:
1. Bring the battery to room temperature (77°F (25°C)).
2. Measure the OCV. Continue to Step 3 if it is at least 12V; otherwise terminate
the procedure and reject the battery.
3. Charge the battery using a 0.05C
10
constant current for 24 hours. The charger
should be capable of providing a driving voltage as high as 36V. Monitor the
battery temperature; discontinue charging if the battery temperature rises by
more than 36°F (20°C).
4. Allow the charged battery to stand on open circuit for a minimum of one hour
before proceeding to Step 5.
5. Perform a capacity test on the battery and record the amp-hours delivered. The
longer the discharge the more reliable the result. This is Cycle 1.
6. Repeat Steps 3 to 5. The capacity returned in Step 5 is now Cycle 2. If Cycle 2
capacity is greater than Cycle 1 capacity proceed to step 7; otherwise reject the
battery.
7. Repeat Steps 3 to 5 to get Cycle 3 capacity. Proceed to step 8 if Cycle 3 capacity
is equal to or more than Cycle 2 capacity. Reject the battery if Cycle 3 capacity is
less than Cycle 2 capacity.
8. If Cycle 3 capacity equals or exceeds Cycle 2 capacity, recharge the battery and
put it back in service.
Deep discharge will produce a premature deterioration of the battery and a
noticeable reduction in the life expectancy of the battery.
5. Maintenance
In practice the user usually specifies the maintenance schedule based on site
criticality, location and manpower. The following is the recommended minimum
maintenance schedule:
Every Six Months (Record All Readings)
Measure, at the battery terminals, the string voltage. If necessary adjust the charger
float voltage to the correct value.
Measure individual bloc voltages. The blocs should be within 5% of the average. All
readings should be recorded in a format where sudden deviations and trends are
easily identifiable.
Inspect for loose or corroded connectors, acid leaks and dust. If necessary isolate
the string/blocs and clean with a soft damp cloth. Do not use solvents or scouring
powders to clean the blocs. Contact EnerSys
®
if you have any questions regarding
maintenance.
6. Disposal
Genesis TPPL batteries are recyclable. Scrap batteries must be packaged and
transported in accordance with prevailing transportation rules and regulations.
Scrap batteries must be disposed of in compliance with local and national laws by a
licensed or certified lead acid battery recycler.
7. Shipping
Approved as non-hazardous cargo for ground, sea and air transportation in
accordance with US DOT Regulation CFR and ICAO and IATA Packing Instruction
806. Please see our SDS for complete details at: www.enersys.com.
Temperature F
Charge voltage, Vpc
2.90
2.80
2.70
2.60
2.50
2.40
2.30
2.20
2.10
-40
-22
-4
14
32
50
68
86
104
122
140
158
176
Theoretical cycling (ideal)
V = 0.00004T
2
- 0.006T + 2.5745
Theoretical float (ideal)
V = 0.00004T
2
- 0.006T + 2.3945
and 2.20VPC minium
State of Charge (SOC), %
Open circuit voltage (OCV),
V
10
20
30
40
50
60
70
80
90
100
13.0
12.8
12.6
12.4
12.2
12.0
11.8
11.6
12.84V or higher indicates 100% SOC
®
