Normal charging recharges a fully or partially charged battery to 100%. Normally a charging current is selected which amounts to between 1/20 and 1/10 of the battery capacity. It is important that the charging current is lowered when the voltage which causes gas to develop is reached (gassing voltage). The current is switched off when the battery is charged.
This charging method charges the battery with a current which is between 3 and 5 times greater than the normal charging current, so that the battery reaches an acceptable charge state quickly. When the gassing voltage (2.35 to 2.4 V) is reached, the charging current should be reduced to avoid overcharging. You should only perform a fast charge on a battery in isolated cases.
The battery, charger, and power consumers are all connected to each other. The charger delivers a current which is just enough to keep the battery's charge state at 100%. The battery delivers peak loads to the "consumers". In buffer charging, it is charged with a constant (stable) voltage.
If the battery is charged but not in use, it can self-discharge after a short while. This amounts to 0.1 to 1% per day. Charging with a low current compensates for this discharging. The charging current in this case is 0.1 A per 100 Ah.
Choosing a charger is extremely important for the reliability and life expectancy of the battery. Apart from performance, there are also differences in the charging characteristics and other specific properties.
The characteristic indicates the relationship between charging current and charging time. The charging characteristic is the function of the current (A) in which the charging voltage (U) is presented as a curve.
|The W charging characteristic
For lead-acid batteries.
Fast charging is possible with the correct charging current.
|The IU charging characteristic
For lead-acid batteries but also for gel batteries.
|The IU0U characteristic