Stages of charging a battery

The stages of charging a battery, or the charging process of a battery, is a phase that all batteries must comply with to prevent them from being overloaded. It does not matter if it is a mobile phone battery that receives its current directly from the general electrical network or if it is a question of solar batteries that receive the energy generated directly by photovoltaic solar panels.

Related: Whats is the discharge rate of a Battery?

Stages of charging a battery

All of them must follow the stages of charging a battery to avoid deterioration or major problems such as overcharging. In this article we are going to do a brief review of some concepts that influence the battery charging process, we will also explain what the battery charging curve consists of and, above all, what the battery charging stages are. We explain it in more detail below.

Terms related to the process of charging a battery

Before fully beginning to explain what the battery charging stages are, it is important that we have a brief notion about some concepts that are involved in the battery charging process in order to facilitate their understanding. These are:

1. Voltage: Also known as electrical voltage. It is a measure that quantifies the electrical potential difference between two points. This determines the amount of electrical charge that can pass from one side of a circuit to the other. The voltage of a battery tells us, then, the amount of work that can be done with a specific capacity to deliver electrons to the circuit. The higher the voltage, the greater the work on the electric current and, therefore, the more energy we will have in the battery.
2. Power: Power measures the amount of energy delivered by an element at a specific time. This counts the time in which electrical energy is transferred by a circuit.
3. strong>Current intensity: It is the amount of electrical energy that circulates through a circuit in the unit of time.
4. Overload: This is caused by an excess load. In the case of electric batteries, overload occurs when the circulating current intensity is greater than the maximum current intensity that the battery circuit supports.
5. Electrolyte: Electrolytes are substances that carry an electrical charge since they are made up of free ions. These behave as electrical conductors.

What is the charge curve of a battery?

The battery curve is nothing more or less than the graph in which the behavior and variation of voltage and electric current are expressed in the different stages of charge of a battery —that is, its behavior in hours of charge until the end of the charge—. These are the Bulk stage —in this case the voltage, or Bulk charge voltage, changes radically, as we will see shortly—, the absorption stage and the float stage. This graph, as we explain in more detail in the next point, shows a difference in the behavior of voltage and current, which act in a similar way, but in different periods.

What are the stages of charging a battery

The stages of charging a battery, as we mentioned above, are essential to guarantee the duration of the batteries, prolonging their useful life, and to reinforce safety during charging. This is the process of charging a battery:

1. Bulk Stage: The Bulk stage takes place when the battery comes into contact with the electrical current and begins to store it. What happens in this phase is that the current that passes to the battery is supplied with the maximum intensity of current. This gives rise to a rise in voltage, or voltage, quickly reaching 12.6 V in most batteries —Bulk charge voltage—. Then the voltage reaches its limit. By then, the battery has already reached approximately 90% of its charge. In that time lapse, when the voltage reaches its limit, it increases a few tenths to 14.4 V or so.
2. absorption stage: What happens at this stage is that the charging speed decreases until the battery is fully charged. The battery voltage is still 14.4V—the absorption limit—however, the absorption of the charging current is rapidly reduced. With this, what is achieved is the recovery of the electrolyte in case it has suffered any alteration. In general, the battery electrolyte may have been affected if the battery was completely discharged before applying power to it—and if it had been in that state for a long time. In that case, the absorption stage will be longer.
3. float stage: It is the last stage of charging a battery. In the float stage, what happens is that the voltage of the battery decreases to approximately 13.5 V. The intensity of the current also decreases to 0 when the battery is fully charged.

In general, most batteries work with this voltage range, although depending on the characteristics of each one, the Bulk charge voltage can range between 14.4 or 14.8 V.