You turn the key and hear a clack-clack — or nothing at all. Breathe: most cases are solved in under an hour. This is the exact sequence a professional would follow.

Step 1: confirm it's the battery

Dead or very dim dashboard lights → almost certainly the battery. Normal dashboard but the engine won't turn (a single clack) → possibly the starter motor. Engine cranks strongly but won't fire → not the battery. With a multimeter: 12.6 V = charged; 12.0 V = discharged; below 11.8 V = deep discharge, causing permanent damage by the hour.

Step 2: find the cause

A forgotten consumer (lights, boot lamp), an aged battery (4+ years, sluggish starts) or a charging fault (young battery, no apparent consumer → suspect the alternator).

Step 3: get it started

With jump leads: red to the flat battery's positive, then donor positive; black to donor negative, then to a metal ground on the broken-down car — not the negative post. Start donor, wait 2-3 minutes, start yours, remove in reverse order. A portable jump starter does the same without a second car.

Step 4: recharge properly (or replace)

Starting is not recharging: give it a night on a maintenance charger. If the battery is 4-5 years old or this is the second breakdown, charging only prolongs the agony — deep discharge leaves permanent plate damage.

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