Battery care

How to jump-start your car safely

Flat battery? Here's how to jump-start your car the right way – in the right order, without sparks or damage to your car's electronics.

Check your owner's manual first. Many modern cars – especially BMW, Mercedes-Benz and Audi – have special jump-start points or a set procedure. Getting it wrong can damage the car's computers. Why modern cars need care. Not sure? Call us.

Before you start

  • Both cars are 12 V, and the cars aren't touching each other.
  • Handbrakes on, gear in Park or Neutral, ignition off in both cars.
  • Lights, radio, aircon and other switches off in both cars.
  • No smoking or open flames – a battery gives off flammable gas.
  • The flat battery isn't cracked, leaking, swollen or frozen. If it is, don't jump it.
  • Your jumper cables are in good condition, with no bare wire.

Connect the cables – in this order

Red cable first, black cable last. The last clamp goes on bare metal, away from the battery.

FLAT BATTERYyour carGOOD BATTERYhelper car1234ENGINE+−+−
Red cable
1
Red to the flat battery's +

Clamp one end of the red cable to the positive (+) post of the flat battery.

2
Red to the good battery's +

Clamp the other end to the positive (+) post of the good battery.

Black cable
3
Black to the good battery's −

Clamp one end of the black cable to the negative (−) post of the good battery.

4
Black to bare metal on the flat car

Engine block or a bare metal part – not the flat battery, and away from fuel lines.

Why not the flat battery's − post? The last clamp can spark. Connecting it away from the battery keeps that spark away from the gas a battery gives off.

Start the car

  1. A
    Check the clamps

    Make sure all four clamps are tight, and stand back from the batteries.

  2. B
    Start the helper car

    Let it run for a few minutes to give the flat battery a little charge.

  3. C
    Start your car

    Crank for no more than 10–15 seconds at a time, and rest between tries. Some manufacturers say to switch the helper car off first – check your manual.

  4. D
    Still won't start?

    Stop after a few tries. The battery may be beyond a jump, or the problem may be the starter, ignition or fuel. Battery or alternator?

Remove the cables – reverse order

Keep both engines running and don't let the clamps touch each other.

  1. Black off the bare metal
  2. Black off the good battery
  3. Red off the good battery
  4. Red off your battery

Never do this

  • Let the red and black clamps touch while connected.
  • Connect red to − or black to + (reverse polarity) – it can damage both cars.
  • Jump a cracked, leaking, swollen or frozen battery.
  • Lean over the batteries while connecting or starting.
  • Jump a 12 V car from a 24 V truck system.
  • Rev the helper car hard or crank your car non-stop.

After the jump

A jump gets you going – it doesn't fix the battery.

30minutes
Keep driving

Drive at speed to put charge back. Don't switch off after a short trip.

Freetest
Get it tested

Within a day or two, at Brackenfell or Stellenbosch. We check the battery and your car's charging system. What the results mean

2ndjump?
Time to check

It may need replacing, or something is draining it. Why batteries go flat

Rather not jump it yourself?

We do jump starts – WhatsApp or call and we'll confirm when we can get to you. If the battery is finished, our technician can bring and fit a new one on the spot.

WhatsApp us
Which branch are you closest to?Brackenfell Stellenbosch
Call us
Which branch are you closest to?Brackenfell 072 381 0812Stellenbosch 067 564 3339

General guidance only. Always follow your vehicle owner's manual.