LEAD-ACID BATTERY
Our discussions thus far have been related to controlling our Electric Forklift so that the driver can perform his/her duties smoothly. We must not forget the one device that enables us to operate the forklift without fuel or cords tying us down. The largest player in our electric game is the Lead - Acid Battery. The battery is a DC source consisting typically of two or more cells which converts chemical energy into electrical energy.
The theory of operation of our forklift battery is the same as our automotive battery. Our automotive battery obviously operates on a slightly smaller scale. Like the batteries used in our personal vehicles they are made up of individual cells connected in series. The number of cells used depends on the voltage required. Our automotive batteries are rated at twelve volts and I'm sure that most of you have noticed that you have 6 individual filling ports for adding water. Each individual filling port represents one battery cell. The cells in any lead - acid battery is equal to approximately 2.0 to 2.2 volts per cell. That means that your typical car battery may charge as high as 13.2 volts (2.2 volts/cell multiplied by the number of cells, in this case 6 cells). The forklift battery measures the same way. As an example a 36 volt forklift battery is made up of 18 individual cells, which means a fully charged 36 volt battery may reach as high as 39.6 volts (18 cells multiplied by 2.2 volts/cell). Some mechanics actually refer to a battery as a representation of the number of cells, a 36 volt battery may be referred to as an 18 cell battery.
A lead - acid battery is filled with a solution of sulfuric acid and water called the electrolyte. Electrolyte by definition is a substance or solution in which the conduction of electricity is accompanied by a chemical action. The chemical action produced by discharging a battery actually turns our electrolyte solution more and more into water. Since this chemical action is reversible by recharging the battery and chemically changing our electrolyte back to its original formulation our lead - acid battery is called a secondary battery, as opposed to a primary battery which is not rechargeable.
This article comes from an excerpt of the new training manual entitled: "Forklift Electronics" written by Robert Meyers. The manual includes over 70 pages of basic electronics, panel parts, directional circuits, how to use a VOM and much more. More than 60 drawings are used to help in the explanation of the SCR cycle, basic control features and all the other articles contained in this new manual. The four color printing and comprehensive four page index makes it a reference manual you'll keep as long as you're servicing electric forklifts. For more information visit the "FORKLIFT ELECTRONICS" Training Manual web page.