When is your car battery too old?

When is your battery too old? How do you know? When should you change it? Read on and let Haynes take all of the guesswork out of battery health.

Many people will tell you the engine is the heart of the car, but that’s not really the case. It’s the battery that provides the spark, the life if you will, to your pride and you. And that’s why you need to make sure it’s happy and healthy.

A tired old battery will let you down, it could cause electrical problems within the car’s systems and it will mean you can’t listen to The Archers. Bad times. So, to avoid all that, here’s what you need to do to check your battery’s health. 

Make a dash

Has the little battery indicator appeared on your dash? This doesn’t always mean the battery is it fault, it actually means there is a fault in the charging system. So it means the car is now relying on the power in the battery and nothing more, and it will run out quickly. It could something as innocuous as a loose terminal or bad earth, or it could be something more serious like a snapped auxiliary belt or failing alternator. 

What’s the colour?

Most modern batteries will have a visual indicator. If you look directly down on the battery, there will be a round shaft you can look down. If it’s green, the batter has at least 75% charge, if it’s black, it needs charging, if it’s red, it’s dead (needs distilled water, but as most modern batteries are sealed, it’s now scrap).

Hot or cold

One of the first warnings that your battery is on its way out is how it performs on a seasonal basis. In warmer weather, the battery doesn’t have to work as hard as it does on a cold winter’s morning. So if your car is letting you down in winter, this could well be it. 

Use a multi-meter

The easiest way to check a battery’s health is to run a multi-meter on it. You can get one for a tenner online, and then you just need to set it to volts and put the connectors on the battery terminals. You should be seeing 12.7 volts for excellent health, 12.4 is okay is okay, whereas anything less than 12v is a battery running out of life. Remember, the car runs on a 12v system. 

Size matters

If you drive a 2.5 V6 car, but it has a dinky battery, something is awry. You need to check your Haynes manual or owner’s handbook to make sure your battery is the right size. A small battery will have fewer CCAs (cold cranking amps) and a lower AmpHour rating, meaning it will struggle with a bigger engine, or a diesel engine. 

Terminal failure

Your battery could be perfect, but if the terminal clamps on your car are covered in filth, old or battered, the battery’s power is a moot point – it can’t get past the connectors to the car. Your terminals need to be bright, clean and free from grease, dirt or any other detritus.