How do generator batteries work?

The primary function of a battery in a generator is to provide the initial energy needed to start the generator's engine.

Generator batteries, often found in portable generators or backup power systems, work much like batteries in other applications, such as those in cars or small electronics.

Here's how generator batteries typically work:

Starting the Generator: When you attempt to start a generator, you engage the starter motor. The starter motor requires a significant amount of electrical power to turn the engine over and start the combustion process. The battery provides this initial burst of electricity.

Chemical Reaction: The battery contains chemical compounds that undergo a chemical reaction to produce electrical energy. In most generator batteries, lead-acid batteries are commonly used. They consist of lead plates submerged in an electrolyte solution of sulfuric acid.

Lead-Acid Battery Operation:

  • Lead Plates: Inside the battery, there are lead plates, typically coated with lead dioxide (positive) and pure lead (negative).
  • Electrolyte: The sulfuric acid electrolyte allows for the flow of ions between the positive and negative plates, creating an electrical potential.
  • Electrochemical Reaction: When the generator is running, the battery's chemical reaction produces electrons, creating a flow of electric current. This current is what powers the starter motor.

Recharging: Once the generator is running, the engine's alternator takes over the task of generating electricity to power the electrical components of the generator and to recharge the battery. The alternator produces electricity through electromagnetic induction, converting mechanical energy from the engine into electrical energy. This recharges the battery, replenishing the chemical reaction for the next start-up.

Maintenance: Generator batteries require maintenance, including periodic checks of the electrolyte level (if the battery is not maintenance-free), cleaning terminals, and ensuring proper connections for efficient operation.

Generator batteries play a crucial role in ensuring that the generator can start reliably when needed, especially during power outages or in remote locations where grid power is unavailable.

At Generators For Export, all of our used generators undergo a Pre-Delivery Inspection. One of the steps carried out during the inspection involves checking the state of the battery. Where necessary Generators For Export will replace the battery to ensure the generator we are exporting meets our high standards.

If you are interested in one of our used generators or would like to discuss the state of the your generator battery, get in touch with Generators For Export today. 

Call: +44(0)1386 553344 | Email:

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