Since its invention, the lead-acid battery has been the most widely used chemical power source in both military and civilian fields. Because it uses a sulfuric acid electrolyte that can leak during transport, people tried to immobilize the electrolyte and seal the battery, and so the gel-electrolyte lead-acid battery came into being. Today lead-acid batteries come in all specifications; taking the 12V lead-acid battery as an example, here we introduce how to charge it.

For a lead-acid battery with a terminal voltage of 12V, the normal float-charge voltage is between 13.5 and 13.8 V. If the float-charge voltage is too low, the battery will not fully charge; if it is too high, it causes over-voltage charging. When the float-charge voltage exceeds 14 V, it is considered over-voltage charging.

In charging a 12V lead-acid battery, the initial charging current is usually set to the value specified in the instructions, or to a current equal to 1/10 of the rated capacity.

(1) Float charging. An online battery bank is kept permanently in parallel with the charger and the load line, working as a backup power source. In general, float charging is used, with each cell voltage controlled at 2.25 V for a 2V cell, and the float-charge voltage is observed and recorded regularly. If a cell voltage is low, the battery is undercharged and should be watched closely.

(2) Equalizing charge. An equalizing charge connects each cell in parallel and charges them at a common voltage. If the battery bank has weak cells during float charging, with cell voltage below 2.20 V for a 2V cell, or after three months of float charging, an equalizing charge should be carried out, controlling each cell at 2.35 V and charging for 6-8 hours. Note that the equalizing time should not be too long; then return to the float-charge voltage and observe how the weak cells change. If the voltage is still not in place, repeat the equalizing charge after two weeks. In general, a new 12V lead-acid battery bank will reach a consistent voltage after six months of float charging and equalizing charges.

The above is a brief introduction to charging a 12V lead-acid battery, and we hope it helps you understand the 12V lead-acid battery in more detail.