After reading the battery's open circuit voltage, the load is applied.
As the circuit voltage approaches near steady state, then the pre-charge function is complete.
The open circuit voltage, is measured when the engine is off and no loads are connected.
Open circuit voltage is also affected by temperature, and the specific gravity of the electrolyte at full charge.
The battery's open circuit voltage can also be used to gauge the state of charge.
In this case, the circuit voltages and currents are independent of time.
The basic parameters that need to be evaluated are the short circuit current, open circuit voltage.
The amplitude of each pulse constitutes the open circuit voltage.
When the tester is used, the battery's open circuit voltage is checked first.
The open circuit voltage from the transformer is higher than this, typically in the 5 to 22 volt range.