Varta B39 · Truck battery 12V 45Ah 300A

Varta B39 ProMotive SLI (formerly ProMotive HD) 45Ah 300A 12V Lorry Battery

The Varta B39 lorry battery is the 12 V, 45 Ah model delivering 300 A of cold cranking power (EN), from Varta's ProMotive SLI (formerly ProMotive HD) range, designed for lorries, buses, large vans and machinery. It replaces the original battery in lorries with the 207 × 175 × 175 mm format without any modifications: the same 45 Ah capacity and the same terminal layout (positive on the right).

• High cranking current for large-capacity diesel engines.
• Tolerance of the vibration of thousands of kilometres on the road.
• Reinforced grids and casing for the severe demands of haulage.
• Dependable through repeated starts and while powering cab equipment.

Applications of the Varta B39 battery

The Varta B39 covers the needs of lorries, buses, large vans and machinery with 45 Ah of capacity and a construction built for that use. Check that it matches your current battery in dimensions, terminals and hold-down: this reference weighs 11.05 kg and has a B13 hold-down.

Format and fitting of the Varta B39

In terms of format, the Varta B39 measures 207 × 175 × 175 mm (length × width × height) and weighs 11.05 kg. The positive terminal on the right determines which side the cables sit on: it is the detail that causes the most buying mistakes, so it is worth checking before you order. It uses a B13 hold-down, the system that anchors it to the vehicle's battery tray. Before replacing it, measure the space your current battery occupies: if it matches on all three dimensions and on terminal position, the swap is direct and needs no adapters.

The Varta B39 and the ProMotive SLI range

The ProMotive SLI range is Varta's starter series for commercial vehicles — lorry, bus and machinery — which in the new portfolio brings together the former ProMotive HD (Heavy Duty) and SHD (Super Heavy Duty). It offers a high cranking current for large-capacity diesel engines and a reinforced construction.

Its reinforced grids and separators cope with the vibration and cycling of long-distance haulage and of the most severe use, aiming for maximum service life and starting reliability in fleets that work long hours.

Commercial vehicles demand a high cranking current and stamina against the vibration of thousands of kilometres. This series uses reinforced grids and a rugged construction to withstand repeated starts of large diesel engines and the draw of the cab's auxiliary equipment. This battery used to belong to Varta's ProMotive HD or ProMotive SHD range; following the brand's change of commercial naming (2025), it now forms part of the new ProMotive SLI series.

Why choose a Varta battery

Manufactured by Clarios to German standards, Varta is one of the world's benchmark brands in starter batteries and an OEM supplier to the leading car makers. Choosing it as a replacement guarantees specifications equal to or better than the originals.

Varta combines more than a century of experience with the industrial production of Clarios: it is the battery many manufacturers fit as standard and one of the most recommended by workshops. Like every lead-acid battery, it is 100% recyclable.

More than 100 manufacturing parameters are checked on every Varta battery before it leaves the plant, a level of rigour that explains why so many workshops and manufacturers trust the brand as their first-choice replacement.

Manufacturer's warranty

The Varta B39 battery comes with the official manufacturer warranty. One important warning for commercial vehicles: most lorries carry two batteries connected in series (a 24 V installation). If you replace only one, the new battery ends up working alongside the old one — which has already lost capacity and has higher internal resistance — and that imbalance means one overcharges while the other falls short, shortening the life of the new unit; the manufacturer may regard it as misuse and void the warranty. That is why we always recommend changing both batteries at the same time.

Care and maintenance

In professional use, checking the state of charge and the battery's hold-down regularly prevents breakdowns on the road. Vibration and the high temperatures of the engine bay are what shorten its life the most, so a secure mounting is key. Keeping the terminals clean and tight and checking the charging system extends battery life in vehicles that clock up long hours. A well-maintained battery reduces the risk of downtime caused by a no-start.