Inverter Surabaya

Three Stage Battery Charging

The BULK stage involves about 80% of the recharge, wherein the charger current is held constant (in a constant current charger), and voltage increases. The properly sized charger will give the battery as much current as it will accept up to charger capacity (25% of battery capacity in amp hours), and not raise a wet battery over 125° F, or an AGM or GEL (valve regulated) battery over 100° F.
The ABSORPTION stage (the remaining 20%, approximately) has the charger holding the voltage at the charger's absorption voltage (between 14.1 VDC and 14.8 VDC, depending on charger set points) and decreasing the current until the battery is fully charged. Some charger manufacturers call this absorption stage an equalization stage. We don't agree with this use of the term. If the battery won't hold a charge, or the current does not drop after the expected recharge time, the battery may have some permanent sulphation.
The FLOAT stage is where the charge voltage is reduced to between 13.0 VDC and 13.8 VDC and held constant, while the current is reduced to less than 1% of battery capacity. This mode can be used to maintain a fully charged battery indefinitely.  
Recharge time can be approximated by dividing the amp hours to be replaced by 90% of the rated output of the charger. For example, a 100 amp hour battery with a 10 % discharge would need 10 amps replaced. Using a 5 amp charger, we have 10 amp hours divided by 90% of 5 amps (.9x5) amps = 2.22 hour recharge time estimate.  A deeply discharged battery deviates from this formula, requiring more time per amp to be replaced.
Recharge frequency recommendations vary from expert to expert. It appears that depth of discharge affects battery life more than frequency of recharge. For example, recharging when the equipment is not going to be used for a while (meal break or whatever), may keep the average depth of discharge above 50% for a service day. This basically applies to battery applications where the average depth of discharge falls below 50% in a day, and the battery can be fully recharged once during a 24 hour period.