Vehicle Battery Chargers Buyers Guide | Sealey

The Sealey Buyer Guide to Vehicle Battery Chargers

This guide is designed to help you choose the correct charger to suit your needs from Sealey’s comprehensive range of battery chargers. 

Manual or Automatic?


Basic chargers are manually operated. The user has to decide the level of charge to be applied, monitor the charge status regularly and turn off the charger when the battery is fully charged. Failure to turn off the charger, when the battery is fully charged, can result in permanent damage to the battery and in extreme cases, the battery could explode!


These are often called smart chargers and utilise electronic circuitry that automatically assesses the condition of a battery. They then apply the ideal level of charge to optimise the charging procedure, resulting in a faster, more efficient charge. When the battery is fully charged, they revert to a maintenance mode to keep the battery in a fully charged state. Therefore, there is no risk of damage to your battery.

You need to decide on the type of charger which best suits your requirements.

Maintenance or trickle charging

Trickle Chargers employ the use of electronic battery monitoring to regulate charging rate. This prevents overcharging. Charging your vehicle's battery at a rate similar to that at which it self-discharges, so as to maintain full battery capacity. These tend to be low amperage units (1-2Amp). Charging at too fast a rate, or overcharging can cause damage to the battery. This function is typically used to keep a battery fully charged while in storage over long periods and is very popular for classic cars, or vehicles that are only used occasionally.

Conventional charging

These chargers have the ability to charge a battery from low voltage to fully charged. This can take anything from 6 to 24 hours, depending on the level of discharge.

Engine starter function

This function is typically found on larger, heavy duty chargers and allows you to jump-start a vehicle with a discharged battery.

Additional Functions:

Engine Starter Function

This function is typically found on larger, heavy-duty chargers and provides a high amp boost, which allows you to jump-start a vehicle with a discharged battery. They work by transferring power directly from the internal transformer to a vehicle’s discharged battery. The jump starter function will not charge your battery, but instead provide the necessary power to crank the engine and start the vehicle. Once the engine is on, the alternator will charge the battery. The biggest advantage of portable jump starters is that they do not require the assistance of another vehicle or person.

Desulphation Function

Some chargers also include a desulphation function. Sulphation occurs naturally in batteries. Over time it builds up on the batteries internal lead plates, reducing their efficiency and the lifespan of the battery. The desulphation function creates a pulsed charge, which cleans off the sulphation. Vehicles that utilize “Stop Start” technology may require Smart Chargers to charge their batteries. Always refer to manufacturers specific information prior to charging.

Points to consider

Now you’ve decided on the type of charger you need, there are a couple more points to consider: Bigger batteries require larger output chargers. Therefore, you will need to choose a charger capable of charging the largest battery you are likely to need to charge. Most chargers are suitable for charging Lead Acid Batteries. But not all are suitable for Gel, Calcium or AGM, EFB or Lithium batteries. Always refer to the battery manufacturer for specific charging instructions.

View our current range of Battery Chargers here: