Table is given for 20°C.
Adjust table with 0.022V/°C when deviating from this temperature.
Unloading-end: 11.8V, charge with 13.2-14.4V. Battery will start gassing at 14.4V (do not exceed). Continuus preservation charge max 13.2V. Float charge; 13.4V for gelled electrolyte, 13.5V for AGM (Absorbed Glass Mat) and 13.8V for flooded cells.
Precision of charge voltage is critical to keep sulfatisation at a minimum. An error of 5% may be enough to reduce life substantially.
A newly charged battery will quickly drop to 13.2V and then slowly settle at 12.6V. After full charge let battery rest 20 hours before measuring open circuit voltage. There might be residual surface charges on the conductor plates otherwise.
Equalization charge – maximum 2 hours at 15V. Make sure ventilation is good and battery temperature is constanly monitored.