For lithium manganese batteries (ML), the maximum charge/discharge times (battery life) are affected by the discharge depth (DoD). The calculator can estimate the life of ML batteries at a given discharge depth, and the calculator uses an estimated battery load to determine the battery backup time relative to the discharge depth.
When ML batteries are reused, their capacity decreases when they are full, that is, the time it takes for the battery to discharge to a specified depth of discharge is gradually shortened. The calculator does not take into account this factor, but the obtained results can well approximate the battery life.
This calculator uses the following formula:
y = (a+b*x)/(1+c*x) Or Cycle = (a+b*DoD)/(1+c*DoD)
The relationship between the number of simulated charging / discharge and the depth of discharge is given. A, B and C are constants based on battery test data. Battery discharge time (hourly) times the total discharge time (hours).
The input parameters are:
IBAT — The current consumed by the device when the battery is powered.
DoD — The depth of discharge and the percentage of battery discharge capacity to total battery capacity.
Fig. 1. the relationship between charge / discharge times and discharge depth of ML battery.