When is your battery too old? Car battery not holding its charge? Read on and let Haynes take all of the guesswork out of battery health.
The engine is supposed to be the heart of the car, but that’s not really the case. It’s the battery that provides the spark, 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.
Car battery warning light
Has the little battery indicator appeared on your dash? This doesn’t always mean the battery is at 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?
Some modern batteries have a visual indicator. If you look at the top of the battery there will be a round shaft you can look down. If it’s green, the battery has at least 75% charge, if it’s black, it needs charging, if it’s red, it’s dead.
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 multimeter
The easiest way to check a battery’s health is to run a multimeter 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, whereas anything less than 12v is a battery running out of life. Remember, the car runs on a 12v system.
If you drive a 2.5-litre 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.
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.