How to Jump Start a Car, and When Not To

Sources checked on 12 September 2026: Ford’s battery advice, the AA’s jump-lead guidance and RAC battery guidance. Your exact vehicle and jump-pack manuals take priority.

Check the location before the battery

Do not attempt repairs on a motorway, including its hard shoulder. If you have stopped there, follow the motorway safety guide. Only consider a jump start somewhere suitable for parked vehicles, clear of traffic.

Check whether a jump start is appropriate

Dim lights, clicking or no response can point to a low battery, but they do not prove the diagnosis. Strong cranking without starting can have other causes. If the vehicle keeps stopping or the charge warning stays on, arrange a professional check.

Do not connect equipment to a battery that is damaged, leaking, swollen or suspected to be frozen. Keep ignition sources away. If there is heat, smoke or an unusual smell, move clear and get help. Do not try to investigate damaged high-voltage components.

Use the instructions for your exact model

Find the jump-start section of the handbook for the model, year and powertrain. Check the permitted power source and voltage, designated terminals, earthing point and limits on starting attempts. Read the jump pack’s instructions too. If another vehicle is involved, its handbook must allow it to act as the donor.

Ford’s guidance illustrates why the connection point matters: some models use accessible jump terminals even when the battery is elsewhere. An unpainted piece of metal is not automatically the correct connection point. If you cannot identify the specified point, stop and seek help.

Connecting and disconnecting

Where both manuals allow conventional lead starting, the usual arrangement connects the positive terminals, then the donor negative and the receiving vehicle’s specified earth. The exact order, engine state and waiting times must follow those manuals. Do not improvise a connection to a fuel-system component.

Keep leads clear of fans and moving parts and keep clamps from touching. Use eye protection, remove jewellery and avoid loose clothing. Do not lean over a battery while starting. The AA advises switching both engines off before disconnecting conventional leads in reverse order; check your manufacturer’s sequence.

A jump pack is a separate device with its own power, connection and shutdown procedure. Using one does not remove the need to check the vehicle’s specified terminals or the pack’s compatibility.

Hybrids, electric cars and stop-start systems

Do not apply a generic petrol-car procedure to a hybrid or EV. Low-voltage systems, terminal locations and permitted assistance vary. Never try to jump the high-voltage traction battery. Do not use an EV or hybrid as a donor unless its manufacturer specifically allows that use.

On a hybrid, readiness to drive may be shown by a dashboard indicator even when the engine stays quiet. Follow the handbook and keep the vehicle secured. Stop-start battery systems also need their model-specific instructions; repeated discharge needs diagnosis.

Rain, diesels, vans and motorbikes

Rain does not make every attempt safe. Keep equipment protected from water and follow its instructions; stop if the working conditions are unsafe. Petrol or diesel alone does not establish compatibility. Required current, voltage and battery condition matter.

A motorbike or van is not automatically suitable for leads from a nearby car. Check both manufacturers’ instructions and the equipment rating. Do not bump-start a vehicle as a substitute for checking the correct procedure.

After a successful start

Starting once does not show that the battery or charging system is healthy. Follow the handbook’s advice on charging and checking it. Do not assume a short drive restores a depleted battery. If warning lights remain, it stalls, or the fault repeats, get it assessed before continuing.

For suitable local assistance, call our jump-start service. If a boost is unsuitable, discuss breakdown recovery. We confirm the job and price before setting off, and agree any additional work first.