E T X - S E R I E S L I T H I U M B A T T E R I E S
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Self-discharge Rates
The self-discharge rate is dependent on temperature. At high temperatures (>25°C), the
cell internal resistance decreases so the self-discharge rate increases. See the graph below
for self-discharge rates (in % per month) versus temperature.
Discharge Curves
Voltage is not a good indication of the state-of-charge in lithium batteries. The first
graph below shows the state-of-charge versus voltage at a 1C discharge rate for the
ETX12 (representative of the ETX-Series batteries). Typically, lithium batteries require
advanced methods like current counting to track the charge level. As seen from the
graph, the voltage only varies .4V for nearly 80% of the discharge cycle at 25 deg C.
13.4V is a good indication of full charge, while 12.8V is an indication of full discharge at
25 deg C.
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Discharge Rate (%/Month)
Self Discharge Rate vs Temp