How Do Semi-Truck Batteries Work?

What You Need To Know About Your Semi-Truck's Battery.

For a truck to perform correctly, it needs a good battery inside to power everything. Your truck's battery provides the power to crank the starter and start the truck as well as run a number of accessories that helps you get to you destinations and deliver payloads on time. If the battery fails, the truck sits idle, which is never good for business.

To continue our ongoing series about systems that power your semi-truck, our experts have put together the following article on batteries. If you've wanted to know more about how the battery in your semi-truck works to power the engine and accessories, then you've come to the right place. Read on to learn more about commercial truck batteries.

What Is a Semi-Truck Battery Made Of?

An commercial vehicle's battery is an example of a wet cell battery, with six cells. The cells are a lead storage battery that uses a series of alternate plates made of a lead alloy grid filled that is with cathode plates or coated with lead dioxide. The cells are filled with a sulfuric acid solution, which is the electrolyte.

How Does a Semi-Truck Battery Work?

A commercial truck battery is a rechargeable power source that is used to start the vehicle. The main purpose of the battery is to provide an electric current to the electric-powered starting motor, which will then turn on the chemically powered internal combustion engine. Once the engine is running, power for the car's electrical systems is supplied by the battery, with help from the alternator charging the battery as the vehicle's demands alter.

Starting an engine uses about three percent of the battery's capacity. With this in mind, commercial truck batteries are designed to deliver maximum current for a minimal time period. They are sometimes referred to as "SLI batteries" for this reason, which stands for "starting, lighting and ignition." Aside from starting the engine, an SLI battery supplies power when the vehicle's electrical requirements are more than the supply from the charging system. It is also acts as a stabilizer, which evens out damaging spikes in voltage. During the times in which the engine is running, power is provided by the alternator, which includes a voltage regulator.

Signs Of A Failing Battery

Excess heat is a main cause of battery failures. When the electrolyte evaporates due to high temperatures, the effective surface area of the plates can become exposed to the electrolyte and lead to sulfation.

Sometimes, corrosion at the battery terminals can also prevent a truck from starting. This can easily be avoided by properly applying dielectric grease directly to the terminals.

How Long Does a Semi-Truck Battery Last?

While there is no hard and fast rule on the topic, a 24-volt battery semi-truck battery is designed to last from three to five years on average, and unfortunately, there is no expected semi-truck battery replacement timeline to closely follow.

What To Do When Your Battery Fails

If the battery is discharged to the point it can no longer turn the engine on, it can be jump started via an external source of power, usually another truck's battery. If the alternator and charging system are undamaged, it can recharge the battery when the engine is back up and running. If the alternator is damaged, it will not charge the battery and you will need to find a replacement alternator.

Read more!

If you would like to read more about alternators and starters, we have good news for you! In order to provide you with the most information possible on the systems that power your semi-truck, we have developed a series of technical articles. Here are a few of the articles you can review.

1. How Do Starters Work?
2. What Do Alternators Do?
3. Starter and alternator troubles.
4. Match Made starters and alternators.
5. Is my alternator or starter failing?

Shop Semi-Truck Batteries Now!

Now that you know a little more about the batteries in your commercial vehicle, the next step is to find the right one for all of your needs.