For the purpose of this article, I am going to write about standard batteries, which are based on the principle of lead and sulfuric acid. This relates to most batteries used these days, whether it is a lead-acid, absorbent glass mat (AGM), gel battery or whatever else it is called.
Any battery consists of six cells of 2V each, which are in series – therefore 12V. The basic principle is that you convert the sulfuric acid to lead sulphate by applying electrical power across the poles, in other words charge the battery. When you use the battery, the lead sulfate will break down again to lead and sulfuric acid.
The 2V cells operate at 1.75V when depleted and 2.25V when fully charged.
