How to use a Car Battery Charger

How to use a Car Battery Charger


We’ve all been there. It’s morning and we go to start the car but it just won’t go. A flat or depleted car battery can happen for a number of reasons. Whether it’s for maintenance, because you’ve left your lights on overnight and drained the battery, or the battery itself has degraded over a longer period – we break down how you can use a battery charger to bring your vehicle back to life.

What type of charger do I need?

Depending on the type of vehicle you have and what you’re using it for, you may need to use a variety of chargers. To break it down simply, there are two types of car battery chargers:

Standard charger: A traditional car battery charger, or linear charger, can be used on most cars and has limited features. They charge your vehicle by continuously delivering electricity to your battery, so may over time damage your battery health. Please note, these chargers are generally not suitable for vehicles with start-stop technology.

Intelligent or smart chargers: These more modern chargers have various settings and features that can help to maintain battery health. For example, trickle charging can be used to feed charge into your battery very slowly when a vehicle is out of action for a while, or multi-stage charging can help to maintain battery health.

How to charge a car battery

How you charge a car battery will vary depending on whether you want to get a flat battery started, charge a waning battery, or maintain health during storage. To get started:

To start, thoroughly read your car charging manual. This will help you understand how to use the charger (all chargers will vary depending on make and model) and help you work out how long to charge your battery for. The time for this will vary depending on the type of battery and engine size, although you can expect anywhere between 10 and 24 hours to fully charge a battery.

If you have a voltmeter, before charging you can use it to see how much charge your battery currently has. This is especially important if you’re using an older charger that has limited features and does not turn off automatically.

You should charge your battery at a low level if you have time (under 10 amps) to help maintain your car battery health over the long term, although always check your manual for best practice instructions.  

To connect your charger, first disconnect the battery from your engine, remembering to disconnect the negative (black) lead first to avoid electric shocks.

Then, connect your battery charger, with the positive and negative leads matching (red and black), place the charger away from the battery and turn the charger on.  

Depending on the type of charger it may turn off automatically when it’s done, you may be notified when charging is done, or you may need to come back and unplug the charger when charging is done to avoid affecting battery health.

How to maintain a healthy car battery 

If you want to avoid any battery scares, you can help maintain a healthy battery by:  

Cleaning your car battery: Get rid of any dirt or grime before it has a chance to get into your battery cells and cause damage.

Maintain during downtime: If you have a vehicle that is rarely used or has a long layoff, make sure you regularly charge the battery to avoid it becoming depleted and damaged.  

Avoid over-charging: Over-charging can cause damage to your battery. To avoid this, make sure you charge at a low level and unplug your charger when it’s done.

Replace when required: Generally, car batteries can perform at a good level for 4 years, so you should replace yours at that frequency.

Need a service to check on battery health, or need a full replacement? Use our garage search feature and pay for your repairs or parts in easy to manage pay monthly car repairs. 

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