How do I manage a flat car battery?

Many drivers have experienced that one stressful question, “Why is my car battery flat?!”, which then often leads to panic mode!

Here, we help you understand how to best manage a flat car battery, by providing education on the steps to take when your car battery appears to be flat. We hope this information will help you to calmly, and safely, make informed decisions about how to manage such a situation if it were ever to occur.

You may also find it useful to check out our tips on how to extend your car battery life, including maintenance and testing information to help safely keep, or put you back, on the road

How do I tell if my car battery is dead?

To determine whether your car battery is dead, you need to ask yourself a few questions to first rule out other possible issues. And you need to use three of your key senses to figure out the answers – sight, sound, and smell.

It is likely the car battery is dead if the following apply:

  • If there is no response to ignition.
  • If the starter motor cranks but the engine won’t turn over.
  • If there are sluggish cranking times.
  • If the engine starts but then dies immediately.
  • If there is no door chime or dome lights.
  • If there are no headlights or dim headlights.
  • If the check engine light turns on.
  • If the battery is misshapen.
  • If there’s an odd smell.
  • If there are corroded battery terminals.

Lifewire, who provide expert-created, real-world technology content, has collated a summary list, Five signs of a dead car battery, which could also act as a useful quick checklist when trying to determine if your car battery is dead

What causes a car battery to go flat?

Batteries often go flat owing to human error – somebody leaving their headlights or inside dome lights on, for example.

From an engineering perspective, this overcharging, and the associated excessive current, produces heat that causes significant physical damage and leads to battery failure. Heat can also cause evaporation of water in the electrolyte, which makes the cell dry up.

Battery Corrosion

An undercharged car battery can also dry up a cell and stop a battery from working. When battery voltage drops to about 10.5 volts, the lead plates that make up the battery cells become heavily coated in lead sulfate. Discharging below this point can permanently damage the battery, meaning it will not charge for as long.

Other physical causes of flat battery can include the battery being improperly held in the cradle, causing active material to fall off from the extra motion; corrosion between battery post and cable; and cold weather, which can lead to a myriad of issues.

It could also just be the unlucky case of a ‘bad’ battery that simply needs replacing, or a battery that has been jump-started too many times, which causes irreversible damage.

If a battery hasn’t been jump started more than a couple of times, however, this is an option to get your car moving again. But if that battery is completely dead, and has been jump started too many times, then battery replacement would be the most viable option.

How much does it cost to replace a flat battery?

Vehicle batteries can cost anywhere in the region of $50 to $250, depending on power, size, and quality required – which then depends on the vehicle’s make, model, and engine type.

We offer a great range of vehicle batteries for cars, motorcycles, trucks, marine vehicles, golf carts, heavy machinery, mowers and 4-wheel drives, all of which present real quality at competitive prices. We also offer an incredibly responsive delivery service – including for emergencies and urgent situations – which is managed by our best-in-field, highly experienced battery technicians. You can request a quote for replacement at any time.

Before you replace a battery, however, it is important to know whether it is actually the battery that is the issue, or if something else is preventing your car from starting. Our car battery replacement process considers all possible scenarios, drawing on the wide-ranging knowledge and extensive experience of our battery technicians, who will help you to determine the best, quickest and safest solution to getting moving again.

My Mitsubishi won’t start, is my battery flat?

There are actually two different answers to this question and while most often the answer is “yes” there is another that can be quickly diagnosed.

This relates to what we often refer to as the Mitsubishi Heart Shaped Key.

Inside your key is a transponder chip. Its’ job is to deactivate the immobiliser and allow the car to start.

Why is this often mistaken for a flat battery?

Because the key will still unlock the car and let you use all of the normal functions except start the engine!

Mitsubishi Heart Shaped Key. Circled is the location of the key fob that becomes popped out, which is mistaken for a flat battery
Mitsubishi Heart Shaped Key. Circled is the location of the key fob that becomes popped out, which is mistaken for a flat battery

Now the chip rarely, if ever, fails. What it does do is fall out of the key casing if you drop the key.

The manufacturer does not glue them in. We assume this is to allow for future replacement, although we don’t know for sure.

If you’ve recently dropped your keys and the head (or fob) has popped open – and immediately after this the car won’t start – do this:

  1. search the area where the keys fell for that chip,
  2. pop it back into its socket,
  3. clip the head closed and,
  4. try to start the car.

Note: The safest thing to do any time you drop a Mitsubishi Heart Shaped Key is to first check that it hasn’t popped apart. If it has – search around the area for the small dark grey/black chip and reinstall it into the key head.

If the head is open, the chip is clearly missing. If you cannot find it anywhere, your best bet is to call a local locksmith for advice.

Need to replace your car battery?

Book a battery replacement today or call us if urgent and we’ll be with you within 30-40 minutes.

Posted in

Leave a Comment

Learn More about Batteries: