Flat battery: jump start, replace, or tow?

Most flat battery calls are fixed in ten minutes. The ones that are not are usually the cars that got jump started, drove for twenty minutes, and stopped again in a worse spot.

Signs it is the battery

• Slow, laboured cranking, or a rapid clicking when you turn the key
• Dash lights dim heavily or the dash resets when you crank
• Nothing at all after the car sat unused for a week or more
• Interior light or headlights left on overnight

Signs it is something else

If the car cranks strongly but will not fire, the battery is probably fine and you are looking at fuel, spark or an immobiliser issue. If the battery light stays on while driving, or the car dies again shortly after a successful jump, that points at the charging system rather than the battery, and another jump start just buys you a few more kilometres.

When a jump start is the right call

A healthy battery that has been drained by lights or a short trip pattern will usually take a jump and then recharge as you drive. If your battery is under about three years old and this is the first time it has happened, a jump start is well worth trying before you spend money on a tow.

When to skip straight to a tow

Battery older than four or five years and already flat twice this month, visible swelling or leaking, or a car that dies again the moment the leads come off; in those cases a tow to your mechanic is the cheaper outcome. We will tell you honestly which situation you are in when we look at it, rather than jumping it and driving away.

Preventing the next one

• Take a longer drive occasionally if you only do short trips
• Get the battery tested at service time once it passes three years
• Check the terminals are clean and tight
• If the car sits for weeks at a time, consider a trickle charger