Will A Float Charger Charge A Dead Battery. Float chargers automatically shut off when the battery is fully charged. Hence the float charging method is used in emergency conditions or for backup power.
You may need to hook jumper cables up to a really dead battery for 5 or 10 minutes to give it enough of a surface charge and then hook up the charger afterward. Without the right battery or charging device you can discover yourself literally dead inside the water. When this is detected at point 3 the charger goes into float charging mode at about 23 volts cell to complete the fill and to maintain the battery.
Float charging is most commonly used for backup and emergency power applications where the discharge of the battery is infrequent.
By definition float chargers are not meant to totally recharge a battery. This type of charger would assume this battery is dead and would not try to charge it. By definition float chargers are not meant to totally recharge a battery. The charger will fast charge the battery to 147V 74V and enter a compensation mode.
