A Comprehensive Guide to Car Battery Chargers

Outfitting automotive workshops goes beyond basic tools. Efficient, safe, and quality vehicle maintenance and servicing depend on specialised equipment such as lifts, air compressors, engine hoists, and vehicle diagnostics. This equipment deals with most vehicles coming through the doors. Well-equipped shops will additionally have at least one battery charger to restore charge in cars with dangerously low battery levels.

Battery Charger Basics

Chargers connect to a mains supply and convert AC power into usable 12VDC or 24VDC battery power. They’re useful in recharging dead batteries, help maintain optimal battery health, and maintain charge levels in unused or garaged vehicles. There are several types of quality commercial chargers to shop from.

Standard Chargers

These are the most affordable types, with simple and compact designs, often compatible with most conventional 12V lead-acid and some gel batteries. They charge batteries using a constant voltage until they are charged, after which the charger needs to be manually disconnected.

Failing to do so on time can lead to overcharging, overheating and damage. The scant safety features and the fact that the chargers are not suitable for cars with start-stop systems limit their use to older vehicles. Charging times to full capacity vary vastly between units, ranging from 2.5 hours in 20A chargers to 24 hours in smaller and cheaper 2A units.

Portable Smart Chargers

Battery charging technology and safety have come a long way, especially with the invention of compact, capable and lightweight smart chargers. These use multiple charging stages with varied current levels to fully charge batteries. The devices also prolong battery lifespans by monitoring battery status (voltage, current and temperature) to prevent overcharging and undercharging.

They also have a trickle or maintenance mode to top up slightly depleted units. While more capable and easier to use than standard types, smart chargers also need more time to fully charge higher-capacity batteries in utes, trucks and cars with diesel engines.

Workshop Chargers

These are bigger, more powerful, suited to charging all vehicle batteries (including deep cycle types) and fully featured. They’re also more dependable, better built, and more versatile. To justify the higher purchase price, commercial chargers differ from standard and smaller portable chargers in a few key ways:

• High-capacity charging – With amperages 10 to 20 times larger than compact chargers, workshop types offer significantly faster charging times. For instance, a 100A commercial charger can fully top a depleted 100Ah battery within an hour. And batteries with 20 to 50% remaining charge are ready for use in less than 30 minutes. This also means faster charging in batteries with higher capacities.
• Charge multiple types of batteries – Commercial variants are suited for all vehicle batteries. This includes lead-acid, gel, AGM, lithium, and deep cycle batteries in 6, 12 or 24V. High-end units also automatically adjust parameters for each type to ensure safety and speed.
• Multiple charging stages for maximum efficiency – To ensure a complete and healthy charge, while also maintaining optimal battery chemistry, commercial chargers use several charging stages. First is the desulphation/soft start stage, which removes sulphate crystals from discharging. Bulk charging at higher current and lower voltage tops batteries to 80% of full capacity. Chargers then increase voltage above 14V in the absorption stage and gradually decrease current until the battery is fully charged. The process is completed with float or maintenance charging to keep the battery at 100% and prevent discharging.
• Heavy-duty builds – Aluminium outer casings shield internal components from impact, heat, humidity and workshop chemicals. Circuit boards include acrylic coatings that resist corrosion, and temperature sensors ensure all power components work within defined limits.
• Multiple outputs – Commercial-grade chargers have up to four separate outputs, to charge four batteries in a single go, regardless of type or capacity.
• Jump start/power supply function – The high current output in many workshop chargers means they can also be used to jump start a car with a flat battery. The chargers are also effective as a replacement power supply during routine maintenance, such as ECU programming.
• Safety features – Short circuit, overcharge, temperature compensation, and reverse polarity protection are several key safety features that ensure the battery and charger work effectively and avoid damage. The device detects abnormal changes in electrical flow, incorrect polarity during connection, and higher temperatures during charging.

Uses In and Outside the Workshop

Heavy-duty chargers are a workshop necessity. They can be used with varied mains output voltage, provide fast, efficient and safe charging in multiple battery types, and ease of use with simple interfaces and legible displays. And they’re the only chargers that can handle high-capacity and high-voltage batteries during regular servicing and repairs. With multiple outputs and high current ratings, they can also charge several batteries simultaneously.

Outside cars, utes, vans and motorcycles, the chargers can replenish depleted batteries in heavy-duty commercial, agricultural and recreational vehicles and machinery, including tractors, harvesters, excavators, caravans, boats, buses and trucks.