Table 10 End of Discharge – Effective ALM 12V7 s-Series Terminal Cut-Off Voltages in
Different Series Configurations
ALM Configuration
Typical Observed ALM Terminal
Cut-Off Voltage (V)
Average Voltage per Cell (V)
Absolute Minimum ALM
Terminal Cut-Off Voltage (V)
1S ‐ (12 V)
9.8
2.45
8.00
2S ‐ (24 V)
20.3
2.54
16.00
3S ‐ (36 V)
30.7
2.56
24.00
4S ‐ (48 V)
41.1
2.57
32.00
406014-02EN, Rev. 05
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ALM
®
12V7 s-Series User’s Guide
Chapter 5: Operation and System Design Considerations
NOTE
Under voltage protection creates an open circuit, removing voltage from the terminals. With a lead-
acid battery, finding no voltage at the terminals often indicates the battery is no longer usable. With
the ALM 12V7 s-Series battery, no voltage at the terminals typically means the cell protection
circuitry has interrupted current to protect the battery. Simply connect the battery to a charge source
to restore voltage to the terminals.
Smart Charger Support
Smart charger technologies require the presence of a terminal voltage before supplying a
charge current. To support smart chargers when in a protection state (i.e. Under Voltage
Protection (UVP) the ALM 12V7 s-Series will present a current limited terminal voltage. When
there is no charger or load connected, there is no current flowing so the circuit allows the
terminals to show the actual battery voltage. This terminal voltage can be measured with a
multi-meter or other high impedance voltage measurement device.
Over Charge Protection
Similar, but opposite to the case at low States of Charge, the ALM 12V7 s-Series battery’s
terminal voltage begins to rise rapidly at high States of Charge. The ALM 12V7 s-Series is
considered at 100% SOC when the cells are balanced and terminal voltage measures 13.8
volts or above. At this point, the average cell voltage is the terminal voltage divided by 4. The
ALM12V7 s-Series batteries are designed to enter an Over Voltage Protection (OVP) state if
any cell rises above 4.1 volts. In the OVP state, the ALM 12V7 s-Series will disconnect its
terminals and not accept further charge current. To exit the OVP state, apply a load to
discharge to the battery. The battery will then return to Normal State once the cell voltages
fall below 4.1 volts. For further details, refer to
Over Temperature Protection
The ALM 12V7 s-Series circuitry continuously monitors the battery’s temperature. The battery
will open its terminals when the temperature is too high for safe operation. Do not operate the
battery outside of the operational temperature range specified in
