Is you car having difficulties turning on?

You may just have a car battery that is on the verge of losing its power, which is a scenario you really don’t want to get into while driving or getting ready for work.

Get your car battery tested for free by our reliable mechanics and eliminate the fear of facing a dead battery once and for all. There is never a convenient time for your car battery to go flat.

What is a car battery?

It’s good to understand what a car battery is and does in order to appreciate the importance of testing your car battery and maintaining a battery in good condition.

Your car’s battery is a rechargeable battery that is used to start the vehicle. If you drive an internal combustion engine (ICE) vehicle, when you start your car, the battery sends a voltage to the starter, which provides the spark for the internal combustion engine. In an electric car, the battery also powers the motor, but via electrical energy supplied to the stator from the battery.

Your vehicle’s battery also provides power to the electrical components, such as the radio, lights, wipers, heater, etc.

Car Battery Test

The main symptoms of a dead battery

To assess the signs of a battery on the verge of draining, use a voltmeter to measure the voltage at the terminals. The “minus” must be detached from the car in this situation. 12.4 V and above is normal; 12.4-12 V indicates a little discharge; the car will start, but you must drive longer or charge the battery.

Up to 11 V – the engine, particularly a diesel engine, will not start; charge it immediately. Worse, if the voltage at the terminals is 10-10.5 V, this is very certainly a 100% short circuit in one of the cans, and only a replacement.

Why is it important to test your car battery?

You don’t want to rely on guesswork when it comes to knowing how much life is left in your battery. If you’re super organised and know when it was last changed and how much driving you’ve done with it, then that’s a fantastic start.

But the only way of predicting how much longer your battery will last is by testing it. That’s where the team at Roskill Auto Mechanical can help.

If you don’t test your car battery, you may face an unwanted scenario, such as:

  • Your car won’t start (and you know it always happens when you’re in a hurry or late for work)
  • Your car may stall (possibly in a remote or unsafe place)

How long do car batteries last?

The life of a car battery depends on factors such as:

  • how much you drive
  • the type of driving you do
  • how much you use the battery without actually driving
  • whether there are extreme weather temperatures where you live
  • whether you leave your car sitting without driving it for long periods of time

On the whole, car batteries can start to wear down in as little as three years. If your car battery is between four and five years old, it may be time to replace it. Batteries don’t often last much longer than five years, so if you’re driving around with a battery this old, you may find yourself stalled and stranded.

Car battery voltage test

A simple way of checking your battery’s voltage involves using either a voltmeter or a multimeter. These are small hand-held instruments that are similar in some ways, but they’re not quite the same.

A voltmeter measures the electrical potential difference between two points in an electric circuit (its voltage). A multimeter does more – it is a multi-purpose measuring device which can directly measure various electrical quantities such as voltage, current and resistance.

If you’re just testing the voltage of your car battery, either of these devices will do.

A fully charged battery will measure about 12.6 volts when the car is not running (its resting voltage). When the car is running, a fully charged battery will rise to somewhere between 13.5 and 14.5 volts.

Car battery drain test

If you suspect something is draining your battery, this is a test we can do to determine the culprit. Some mechanics refer to it as a parasitic drain test – because there is a “parasite” that is draining your battery. It’s not an actual parasite, of course. It’s something that is causing your battery to run down when it shouldn’t.

Things that may be draining your battery might include a faulty headlight, alternator, or other rogue electrical part.

Testing for what is draining a car battery involves investigating the fuse panel(s) in your vehicle and checking its electrical components. It’s best to leave this work to the trained and experienced mechanics.

Frequently Asked Questions

One obvious sign that your car battery is flat is the fact that your car won’t start. But don’t jump to conclusions here. There are a number of reasons why your car isn’t starting or is slow to start. A dead battery is just one of these.

The most reliable way of testing whether your car battery is dead is by checking its voltage. The easiest way to do this is by using a voltmeter or a multimeter.

To use a digital multimeter, you begin by testing your car’s resting voltage – turn the lights on (but not the engine). Adjust the multimeter to a setting above 15V. Next, connect the probes on the digital multimeter to the corresponding points on the battery – black to the negative point, red to the positive point. When connected to a fully charged battery, the multimeter will show your battery’s voltage as being between 12.5V to 12.6V if everything is working as it should be.

We advise setting the multimeter to about 20V of DC voltage. Setting it to 20V isn’t a must; the important thing is that it’s above 15V, so you get the correct reading.

You can get your car battery tested for free from Roskill Auto Mechanical. There’s no obligation or fine print. We just want you safe on the roads.

Contact us online or call us on 092421870 for a free quote or to book an appointment.


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