HGV Battery Guide: How to Choose the Correct Truck Battery

Choosing the correct battery for an HGV is about much more than simply finding a battery with a high Ah or CCA rating. Trucks and heavy commercial vehicles can use different battery sizes, terminal layouts and technologies, and many operate with two 12V batteries working together as a 24V starting system.

In this guide, we explain the main checks to make when replacing an HGV battery and how to identify the correct Lucas battery for your truck.

Already know what you need? Browse our Lucas HGV batteries, including popular 625, 627 and 629 commercial battery formats.

What should you check when choosing an HGV battery?

Before ordering a replacement truck battery, compare the new battery with the specification and physical layout of the battery currently fitted. The most important checks include:

• Voltage – normally 12V per battery, although two batteries may form a 24V system.
• Battery technology – conventional flooded, EFB or AGM depending on the vehicle.
• Capacity (Ah) – the battery's rated amp-hour capacity.
• Cold cranking amps (CCA) – its ability to deliver high starting current.
• Dimensions – length, width and total height must suit the battery tray and available space.
• Terminal layout – check the position of the positive and negative terminals.
• Hold-down and mounting – the battery must be secured correctly in the vehicle.

If you're unsure what the numbers and codes on your existing battery mean, see our guide to reading a battery label.

Are HGV batteries 12V or 24V?

Many HGVs use a 24V electrical system made from two matched 12V batteries connected in series. When two 12V batteries are connected in series, their voltage combines to provide 24V, but their Ah capacity does not double.

For example, two matched 12V 180Ah batteries connected in series form a nominal 24V 180Ah battery bank, rather than a 24V 360Ah bank.

This is one reason it is important to identify the complete battery system rather than looking at the specification printed on just one battery.

Should both HGV batteries be replaced together?

Where two batteries operate together as the truck's starting bank, they should normally be closely matched in specification, technology and condition. A new battery paired with an older, deteriorated battery can result in uneven performance and charging.

If one battery appears to have failed, the sensible first step is to test both batteries and check the vehicle's charging system before fitting replacements. Our battery testing guide explains some of the basic checks involved.

What are 625, 627 and 629 HGV batteries?

625, 627 and 629 are familiar UK commercial battery references found across truck and heavy commercial applications. They should not be treated simply as different capacities of the same battery because their physical formats and specifications differ.

627 HGV battery

The 627 is a long commercial battery format used in suitable truck applications. Always check its dimensions, terminal position and electrical specification against the battery being replaced.

You can view the Lucas 627 12V 120Ah commercial battery for the complete product specification.

629 HGV battery

The 629 uses a deeper commercial battery case and is available in higher-capacity configurations. Again, the reference number alone does not confirm that it is suitable for a particular truck.

For example, see the specifications for the Lucas 629 Supreme 12V 180Ah commercial battery.

625 HGV battery

The 625 is another large commercial battery format used across suitable heavy vehicle applications. Capacity, cranking performance and other specifications can vary between product ranges, so the complete specification should always be checked.

You can compare 625, 627, 629 and other options in our complete HGV battery range.

Why terminal layout matters on a truck battery

Two batteries can appear very similar and still have different terminal positions. On a large commercial battery, fitting the wrong terminal layout may mean the vehicle's cables cannot reach safely or the battery cannot be installed in its intended orientation.

Never rely on Ah or CCA alone. Compare the positive and negative terminal positions, terminal type, battery dimensions and retaining arrangement with the existing installation.

Does an HGV need AGM, EFB or a standard battery?

The correct battery technology depends on the vehicle and how its electrical system is designed. Some trucks use conventional commercial starting batteries, while vehicles with higher cycling demands, Start-Stop systems or extensive electrical equipment may require EFB or AGM technology.

If the vehicle was designed for AGM or EFB batteries, do not downgrade it to a conventional flooded battery simply because another battery has similar dimensions or capacity.

Don't choose an HGV battery by Ah alone

A higher Ah figure does not automatically mean that a battery is a better replacement. Ah describes capacity, while CCA describes starting performance under a defined cold test. Neither tells you whether the battery physically fits the truck or has the correct terminal arrangement.

The correct replacement needs to satisfy the vehicle's electrical requirements and fit the original installation correctly.

For a broader explanation of battery specifications and fitment, read our guide to choosing the correct battery.

HGV battery or commercial battery?

Not every commercial vehicle requires one of the large HGV battery formats. Vans and medium commercial vehicles can use smaller battery types, while heavy truck starting systems commonly use larger commercial formats.

If you're looking beyond the larger HGV formats, browse our wider Lucas commercial battery range.

Find the correct Lucas HGV battery

If you already know the battery reference or dimensions you need, browse our Lucas HGV battery range.

If you're unsure, make a note of the vehicle details and photograph the labels and terminal arrangement of the batteries currently fitted. Comparing the existing battery's voltage, technology, Ah, CCA, dimensions and terminal layout gives us much more information than the vehicle registration alone.

Need help? Use our Battery Help & Advice centre or contact our battery specialists before ordering.