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
15
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
