cycle consists of a constant current
source, NOT a constant voltage. The current
is set to a value between 3% and 7% of the Amp-hour rating of the battery
. The cycle is applied after the battery
is so-called fully charged and has "rested" for close to 24 hours on float voltage.
The cycle is terminaed when the terminal voltage reaches a value between 16V and 17.X Volts depending upon temperature and battery type unless excess gassing first occurs.
The fact that some chargers and inverter/charger combinations offer a so-called equalization cycle is actually a compromise in offering a relative safe, yet low, terminal voltage without having the ability to operate in a constant-current mode. Keep in mind that these chargers are NOT giving you a true equalization cycle yet the offer is better than nothing.
batteries can benefit from a true equalization cycle when necessary yet ALL lead-acid batteries require such a cycle less often if one applies a sufficiently high acceptance voltage when using a 3-step charger
that allows settability of the acceptance voltage. This is why a MINIMUM acceptance voltage is 14.4 V @ 20 deg. C. When using lower voltages for deeply discharged batteries equalization will be necessary more often.