The batteries are distinguished mainly by the application:

· Batteries for starting

· Traction batteries

The Starter Batteries (also called SLI = Starting Lighting Ignition) are used to obtain the first combustion in the engine. They have the task of accumulating current while driving through the electrical circuit of the machine and of returning it at any time. These batteries are formed by thin plates that allow you to discharge a lot of energy quickly but do not tolerate being deeply discharged as they would be damaged quickly.

For the starter battery to always remain at its maximum efficiency, it is essential that all the components of the electrical system are subjected to regular checks and that the battery does not remain unused for long periods. For this purpose, after installing the new battery, it is important to make sure that the recharging system brings the battery voltage to 14-14.5 Volts and that the vehicle's electrical system has no absorption greater than 20-30 mA.

The Traction Batteries (Deep cycle battery) instead have thicker plates and separators with glass wool that make them resistant to deep discharges. These batteries, however, do not provide fast discharges like the starting ones even if they can still be used for starting combustion.

The lightweight traction batteries are designed and built-in standard 6-8-12 Volt monoblocks. They are used to store energy and release it in constant and continuous current over time. Mainly used to power small and medium electric motors or for all electrical services, they can be produced with flat or tubular positive plates.

The industrial traction batteries are built-in elements in standard DIN or British 2 Volt sizes. These elements are then assembled in fertilized iron boxes to compose the battery that will give power to medium and large electric motors.


Basically, there are two different types of Lead-Acid battery:

- FREE ACID: where the electrolyte can flow freely between the plates and escape if the battery is turned upside down

- SEALED: in this case the electrolyte is "blocked" through two techniques:

GEL The electrolyte is transformed into a gelatinous substance with the addition of hardening agents

AGM (Acid Absorbed) The electrolyte is absorbed by a fibre separator.

Basically, the battery is characterized by:

Voltage - Expressed in Volts (V): it is the unit for measuring the electrical pressure, the thrust that the Amperes receive in an electrical circuit. A battery consists of a set of electrochemical cells (elements) each having a nominal voltage of 2 Volts. Based on the number of elements connected in series, the final nominal voltage of the accumulator is determined which for starting is generally 6 - 12 or 24 Volt.

Discharge Current - Expressed in Ampere (A): this is the unit that measures the flow of current through a circuit. Also called "inrush" current, it is the ability to start a battery. It defines the maximum current that the battery can supply in a given time before the voltage of every single element drops below a fixed value. It is the characteristic that distinguishes a starter battery from traction. In fact, while for starting the battery must have a high starting point even for a very short period of time, for traction, a relatively low starting point is required for a longer period.

Capacity - Expressed in Ampere/hour (Ah) it is the product given by a current (measured in Ampère) for the discharge time determined in hours. It defines the amount of energy that the battery can deliver in: - 20 hours for starter batteries - 10 hours for stationary batteries - 5 hours for traction batteries.