Signs a jump start will work
A flat battery gives fairly clear clues:
- Rapid clicking when you turn the key or press start.
- Dashboard lights that dim, flicker or go out when you try to start.
- Central locking that is slow or does not work at all.
- The car was left with lights on, a door ajar or unused for weeks.
- A very cold morning after a string of short journeys.
Signs you need recovery instead
A jump start only replaces missing charge. It will not fix a fault elsewhere. Recovery is the better choice when the engine cranks at normal speed but will not start, when there is a smell of fuel or burning, when the battery warning light comes on while driving, or when the car starts after a jump and then dies again within minutes. That last sign usually points to the alternator, which charges the battery while you drive.
Swollen, cracked or leaking batteries should not be jump-started at all. Neither should a car after an accident, or one that has been in flood water.
Jump starting safely
If you jump start the car yourself, follow the handbook: some modern cars have dedicated jump points under the bonnet rather than on the battery. Connect red to the flat battery's positive terminal, red to the donor's positive, black to the donor's negative and the final black to bare metal on the flat car away from the battery. Remove the leads in reverse order. Keep leads away from moving parts, and never jump start on a motorway hard shoulder.
Once running, drive for a good while rather than switching off straight away, and get the battery tested. A battery that has gone completely flat more than once is often near the end of its life.
Why it is worth saying which you think it is
When you call, describe what you see and hear. If it sounds like a flat battery, a jump start is quicker and costs less than a full recovery. If it sounds like something else, the operator can send a truck straight away rather than trying a jump first and then having to come back. We offer both, 24/7, and give you a price before dispatch.
Hybrids, electric cars and stop-start systems
Hybrids and electric cars still have a small 12-volt battery that powers the electronics, and if it goes flat the car may not switch on at all. Many can be jump-started from dedicated points, but the handbook matters more than ever, and some manufacturers advise against using the car to jump another. Cars with stop-start systems usually use special AGM or EFB batteries, which need the correct replacement type. An electric car that has run out of range is a different problem entirely and needs recovery to a charger, not a jump start.
Frequently asked questions
How do I know if my battery is flat?
Rapid clicking, dim or flickering dashboard lights and slow central locking are the classic signs of a flat battery.
My car started after a jump but died again. Why?
That usually means the battery is not being charged while you drive, often an alternator fault. The car needs checking rather than another jump.
Can a jump start damage my car?
Done correctly, following the handbook and using the right jump points, it is safe. Wrong connections can damage electronics, so if in doubt ask for help.
Do you do jump starts as well as recovery?
Yes. Tell us the symptoms and we will suggest a jump start or recovery, and give you a price before dispatch.
Need help now?
We take calls 24/7 and give you a price before anyone is dispatched.
Call 03300 435121