The lead / acid accumulator of which they are composed is called "element": a propylene container in which, in a solution of sulfuric acid and water, positive and negative lead paste plates are immersed, interspersed with porous diaphragms.
We can be of many sizes depending on how many plates we have inside (from 2 or 3 up to 12) and also vary in height, from 25 to 75 cm.
We are made up of several elements assembled in a metal box protected inside by insulating and acid-resistant material (fertene). The dimensional characteristics concern the conformation and dimensions of the containment body, and in most cases they are an integral part of the truck body.
We can be made up of a variable number of elements, according to the characteristics of the machine that we will have to equip. The weight is very important for the static balance of the trolley.
If it were less than a given value, it would lead to the ungovernability of the trolley and to a possible overturning during use. Excessive weight would lead to a decrease in our autonomy.
The rated voltage is expressed in "volts" and is the potential difference between the negative and positive plates immersed in the electrolyte.
Each element has a voltage of 2 volts and therefore the voltage of a battery is equal to double the number of elements that compose it (who has 12 elements is a 24V, who has 36 is a 72V and so on).
Our capacity, on the other hand, is expressed in "amper hours" and is the amount of current that we can supply to the user before the voltage reaches the final value beyond which it cannot go.
If we are charged with a traditional charger, we will have 2 phases: first, the acid comes out of the plates and since it is very heavy and there is no movement, it falls and concentrates at the bottom of the element. Subsequently, boiling occurs and the resulting gaseous exhalation has the effect of causing the acid to rise and homogenize throughout the height. This phase is very important and you need to know how to control it as it contributes to overheating and consumption of the electrolyte: each amp hour of overcharging is equivalent to 0.34g of water dispersed.