Charging your car battery

Often thought of as something to simply replace when they eventually fail, did you know your car’s battery can be maintained and kept healthy?

By following good practice, a car battery’s life can be extended, increasing the vehicle’s reliability while also reducing the frequency of battery replacements, meaning time and money saved in the long run.

If you do have a flat battery or think you need a car battery replacement, call NRMA batteries on 1300 906 479.

Keeping your battery topped up

The lead acid batteries most commonly used in cars don’t like being low on charge, and their lifespan is drastically shortened if kept in low states of charge for long periods.

RELATED: Taking care of your battery

The simplest way to avoid this is to ensure the battery is both recharged often, and uncharged infrequently. The following tips can help to achieve this:

Take a long drive now and then

Batteries work hardest during startup, and while they are recharged under normal driving and engine idle conditions, this process happens much more slowly.

If most of your car’s trips are short ones to the shops and back, it’s likely you’re pulling more from the 12-volt battery than you’re putting back in each time.

If you find your car is having a little more trouble starting than usual, a long drive and a good chance for the alternator to replenish the battery might be just what the doctor (or mechanic) ordered.

Avoid draining energy with the engine off

An engine’s alternator can only provide the electrical current when it’s switched on. If your engine is off, all of your accessories are pulling power directly from your battery.

Try to avoid habits that drain the battery either before the engine has been fired up or after it’s been shut down, such as sitting and listening to the radio, raising or lowering power electric windows and using the air conditioner or fan.

Invest in a charger

The simplest way to keep a battery topped up is by connecting it to a charger. These are designed to refill your battery, and can range from very simple and inexpensive units to more comprehensive and costly versions depending on requirements (see below for more info on the difference).

While the outlay might seem extreme, it’s good to remember that batteries themselves are also expensive, and that the cost of a charger can be quickly recouped via money saved on less frequent battery replacement.

Types of chargers

All chargers are designed to do the same thing, and that’s to increase voltage and stored energy within a battery. How they go about this, however, changes depending on the style of charger.

Due to lead acid batteries working via chemical reaction, recharging them needs to be done in a measured and often slow way to avoid volatility.

Related: How does cold weather affect your car battery?

Enter ‘trickle’ chargers, designed to – you guessed it – trickle current into a battery and restore it to its former glory. Depending on the amperage rating of these chargers, they can take from a few hours to more than a day to fully charge a flat battery.

Choosing the right one for you will depend on your budget, needs and the way the car is likely to be used or stored.

Simple trickle chargers

A ‘simple’ trickle charger will merely convert power – be it taken from a normal electrical outlet of even solar panels – and feed it into a battery.

Simple trickle chargers generally don’t have onboard computers, meaning they can’t ‘speak’ to the battery to check its current state of charge.

This makes them much cheaper, but also means they don’t generally have overcharge protection, meaning users will have to exercise more diligence to avoid overcharging and serious damage to the 12-volt battery.

Smart trickle chargers

Smart trickle chargers use technology to effectively communicate with the battery to calculate its state of charge and can alter their output accordingly.

The largest benefit of a smart charger is in its ability to ‘float’ charge, effectively meaning the charger will switch itself on and off when the battery is fully charged, allowing users to leave them connected indefinitely.

This is great for vehicles that are stored for long periods without driving, such as those in collections or undergoing restoration.

Because these smart trickle chargers can calculate a lot about a 12-volt battery’s condition, they’re also able to ‘recondition’ batteries via various ‘stages’ of recharging, and have even been known to bring almost completely dead batteries back to life.

Battery charging checklist:

•    Before charging the 12-volt battery, check the battery case for cracks. If there is any sign of damage, replace the battery. 

•    When charging your battery, make sure there are no flammable objects around - battery gases are very flammable and are easily ignited. 

•    If you live or visit alpine regions never charge a frozen battery, as they can explode if charged while frozen. 

•    If the battery has vents, check these are clear of fragments or other blockages. 

•    Always connect the charger to the battery before switching the charger on. 

•    Switch the battery charger off before disconnecting it from the 12-volt battery. 

•    If possible, use a slow battery charge, this is more effective than a rapid charge. 

•    If you notice the battery getting too hot (around 50 degrees celsius), stop charging the battery immediately.