Few things sour a morning like turning the key and hearing nothing but a click. A flat battery is one of the most common breakdown causes, but it's also one of the easiest to fix yourself, provided you have jump leads and another vehicle willing to help. Before you touch a single cable, take a moment to check your handbook for any model-specific warnings, as some cars with sensitive electronics have particular jump-starting instructions.
What you'll need
You'll need a working set of jump leads and a second car with a healthy battery of a similar voltage. Park the two vehicles close enough for the leads to reach without either car touching the other, then switch off both engines and all electrical accessories.
- Connect one red clamp to the positive terminal of the flat battery
- Connect the other red clamp to the positive terminal of the donor battery
- Connect one black clamp to the negative terminal of the donor battery
- Connect the final black clamp to an unpainted metal point on the flat car's engine bay, away from the battery itself
Starting the engine
Start the donor vehicle and let it run for a few minutes to build some charge. Then attempt to start the car with the flat battery. If it fires up, leave both engines running for a few minutes before disconnecting the leads in the reverse order you attached them: black from the engine bay first, then black from the donor, then both reds.
Once you're moving, keep the engine running for a reasonable drive to let the alternator recharge the battery properly rather than switching straight off again.
When it's not that simple
If the car won't start after a couple of attempts, don't keep cranking the starter motor, as this can cause damage. It may be a sign the battery is beyond a simple jump start, or that there's a deeper electrical fault. In that case, it's worth calling a breakdown service or garage rather than persisting.
A jump start gets you moving again, but it doesn't fix the underlying cause. If your battery keeps going flat, get it tested properly so you're not caught out again at a worse moment.
