Guide
How to Jump Start a Car Safely, and When to Stop Trying
Connect red to the flat battery's positive, red to the donor's positive, black to the donor's negative, then black to bare metal on the flat car away from the battery; start the donor, wait a few minutes, then start the flat car. If the battery is swollen, leaking or smells of rotten eggs, or the car still does not crank after two or three attempts, stop and call for help.
By Discovery Gardens Battery · Updated
Before you start: the safety stop
Do not jump start if the battery case is swollen, cracked or leaking, if you smell rotten eggs or see smoke, or if the battery is frozen. Keep sparks and cigarettes away, and never lean over the battery while connecting cables.
Check the owner's manual first. Many modern cars have a dedicated jump terminal under the bonnet or at the fuse box, and the manual will show where it is and whether the maker allows jump starting at all. If the manual and this guide differ, follow the manual.
Jump start cable order, step by step
You need a set of jump leads and a donor car with a battery of the same voltage (12V for almost all cars). Park the donor close enough for the leads to reach without the cars touching. Switch both cars off, apply the handbrakes and turn off lights, AC and 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 last black clamp to an unpainted metal earth point on the flat car's engine or body, away from the battery. Not to the flat battery's negative terminal: a battery can give off hydrogen, and the last connection is the one most likely to spark.
- Start the donor car and let it run for three to five minutes.
- Try to start the flat car. Crank for no more than about 10 seconds at a time.
- Once it runs, remove the leads in reverse order: black from the earth point, black from the donor, red from the donor, red from the formerly flat battery. Keep the clamps from touching each other or any metal while you do.
| Order | Clamp | Connect to |
|---|---|---|
| 1 | Red | Flat battery + |
| 2 | Red | Donor battery + |
| 3 | Black | Donor battery − |
| 4 | Black | Bare metal earth point on the flat car, away from the battery |
| Remove | All | Reverse order: 4, 3, 2, 1 |
Using a booster pack in a basement or tight bay
In Discovery Gardens and the towers nearby, a lot of cars are parked nose-in against a wall or deep in a basement, where no second car can get close. A portable booster pack (a jump starter with its own lithium or lead-acid battery) solves this, and it is what our technicians carry for exactly these spots.
- Make sure the pack is charged and switched off.
- Connect the red clamp to the flat battery's positive (+) terminal or the car's jump terminal.
- Connect the black clamp to an unpainted metal earth point, or to the negative terminal if the pack's instructions allow it.
- Switch the pack on and wait for its ready indicator.
- Start the car. If it does not crank, wait about a minute before the next try so the pack and starter can recover.
- Once the engine runs, switch the pack off and remove black first, then red.
A booster pack left in the boot through a UAE summer will lose charge and age faster, like any battery. Check its charge every month or two.
Modern cars, start-stop and hybrids
- Electronics: voltage spikes can upset control units. Use good-quality leads, make firm connections and never disconnect while either engine is cranking.
- Start-stop cars: these usually use an AGM or EFB battery and often have a battery sensor on the negative terminal. Connect the black lead to the earth point the manual specifies, not to the battery negative, so the sensor is bypassed.
- Hybrids: the car is started by the 12V auxiliary battery, which may be in the boot or under a seat. Use the manufacturer's 12V jump terminal under the bonnet or in the fuse box, as shown in the owner's manual. Never connect to anything orange: orange cables are high voltage. Our hybrid 12V battery guide covers this in more detail.
- Do not use a hybrid as a donor unless its manual says you may. Many makers do not allow it.
When to stop trying
Repeated cranking does more harm than good. It overheats the starter motor, drains the donor and can damage a weak battery further. Stop and call for help if:
- The car still does not crank after two or three attempts with the donor running.
- You hear rapid clicking even with the leads connected, which can mean a very deep discharge, a poor connection or a starter fault.
- The engine cranks normally but does not fire. That is not a battery problem.
- The leads or clamps get hot, or you see sparks at the battery.
- Any of the safety-stop signs at the top of this page appear.
Our homepage battery care tips put it simply: don't crank it to death. A technician can test the battery and alternator on the spot and tell you which one is at fault.
After the jump: why it can be flat again tomorrow
A jump start only gets the engine running. It does not repair the battery, and the alternator is not designed to bring a deeply flat battery back to full charge quickly.
Drive for at least 30 minutes, ideally on open roads such as Sheikh Zayed Road rather than stop-start traffic. Short hops inside Discovery Gardens, from one cluster to the supermarket and back, do not give the alternator enough time to replace the charge used in starting. Keep the AC and accessories modest on that first drive if you can.
If the battery is more than about two years old, or it went flat without an obvious reason such as lights left on, it is likely to fail again. Have it load tested. If the battery light came on while driving, read our guide on battery or alternator faults before buying a new battery.
Get a jump start from us
If you would rather not do it yourself, our car jump start service is AED 99 flat, 24/7, with no night or weekend surcharge, and includes a battery and alternator health check. We arrive in about 20–30 minutes with a booster pack that works in basements and nose-in bays. If the battery has failed, we quote a replacement on the spot and can fit it there and then. Call or WhatsApp +971 54 309 1289.
Questions
What is the correct order to connect jump leads?
Red to the flat battery's positive, red to the donor's positive, black to the donor's negative, then black to unpainted metal on the flat car away from the battery. Remove them in reverse order.
Can I jump start a car without another car?
Yes, with a charged portable booster pack. It is the easiest way to jump start a car parked in a basement or nose-in against a wall.
How long should I drive after a jump start?
At least 30 minutes, ideally on open roads. Short trips do not recharge the battery, and an old battery may need replacing anyway.
Can you jump start a hybrid car?
Yes, through the manufacturer's 12V jump terminal under the bonnet or in the fuse box, as shown in the owner's manual. Never touch the orange high-voltage cables.